One of the great treats of being a partner at 475 High Performance Building Supply is the annual trip to the International Passive House conference – this year in Leipzig, Germany,  April 17^th and 18^th. We have the opportunity to see customers from across North America, visit our leading product suppliers and stay up-to-date on the cutting edge of low-energy high-performance building. Returning to the U.S. I was happy to write a conference  review for GreenBuildingAdvisor. This is a remix of that post – with more on our products, our customers and the great fun that was had. As with the other conferences before, there was a dizzying array of information sharing and professional networking – I’m going to try to boil it down to a few themes.

It’s the Components

Plenary Session, PHI

A key theme to delivering solutions in any particular place was the development and availability of the best possible components. Dr. Wolfgang Feist, Director of the Passive House Institute (PHI), opened the conference with a detailed analysis of developing component technologies of insulations, windows, and ventilation, heating, cooling and dehumidification systems. “Today the investment costs for improved efficiency of building components are exceptionally low; the cost difference is more than compensated through the saved energy costs,” said Dr. Feist. As we see certified windows get better while costs drop, it was clear that the large scale manufacture, and wide availability and application of critical components is essential to making their cost effectiveness a reality everywhere. Building on the success of window components, senior PHI scientist Dr. Benjamin Krick presented the 2016 Component Awards – focused on window components suitable for retrofit applications. With 41 qualifying entries the quality of the winners was exceptionally high, including First Prize solutions by Optiwin and Smartwin.   The focus on the innovative application of high-performance components was the subject of many sessions, including a session by Allen Gilliland of One Sky Homes, San Jose, California, on simplified approaches to ventilation and space conditioning. After windows it is clear that ventilation components and applications are very critical to ongoing developments.

The LUNOS Nexxt

Lothar Moll (left) with Chris Herring of Green Building Store and PassivhausTrust

On the expo floor it was nice to spend time with Lüder Herms and Lothar Moll of Pro Clima.   Pro Clima is a leader in complete airtightness and moisture control systems for high-performance enclosures and they have a long association with the Passive House Institute.

Lamilux skylight

LAMILUX was also in the house, with a full array of triple pane, Passive House certified and Passive House compatible skylights and glass roofs.

It’s the Retrofits

While the discussion of retrofitting existing building is not new to Passive House, each year the dominance of retrofitting grows. PHI’s retrofit standard is called EnerPHit and it is gaining in global application. Susanne Theumer and Maria del Carmen Rivero Arias, both of PHI, presented on a study of the successful application of EnerPHit standard across the 16 climate zones of Mexico. They concluded: “[EnerPHit] has once again proved to be the best option for achieving energy efficiency without compromising comfort or cost efficiency in the case of building modernizations, even for the analyzed examples within the warm and hot climate zones.”

Tomas O’Leary presenting EuroPHit

Many sessions were dedicated to examining retrofits – from a study of 20 residential units in the United Kingdom, to products innovations such as an insulating plaster mix product that incorporates aerogel insulation called “Fixit 222 Aerogel”, to an update on the EuroPHit Project by Passive House Academy Director, Tomas O’Leary.  EuroPHit is a three year project funded by the European Union, of 20 projects located from Spain to Sweden to study step-by-step refurbishment and develop tools and materials for wide scale implementation. Tomas O’Leary stated “EuroPHit contends that it is better to develop a refurbishment plan for buildings which might span several years (or even decades) and to do a deep retrofit on a step-by-step basis to ensure that in the end the EnerPHit standard is reached.”

Other presentations featured retrofits of office complexes, high-rises and historic landmarks. If we needed reminding, it was made remarkably clear, that in many ways, the future is retrofits. Based in Brooklyn, our company was born out of retrofits – and our first free eBook is on High Performance Masonry Retrofits.

It’s the Data

Very high satisfaction measured of Bahnstadt residents.

If you are a data junky then this conference was the place for you. Numerous presentations provided extensive data collected from component and equipment performance to user satisfaction, including extensive data from residents and workers in the new Bahnstadt District in Heidelberg, Germany. Nick Grant of Elemental Solutions in the UK, showed how data collected over several school projects informed the teams evolving process of design and PHPP optimization to make ever better school buildings. His presentation is online here.

It’s the Energy Transformation

Ensuring that our buildings are rigorously efficient, and add renewables in a way that supports and optimizes society’s shift to renewable energy production, the Passive House Institute has introduced a new visionary primary energy calculation, Primary Energy Renewable (PER) and new Certification levels Plus and Premium which acknowledge the benefits of renewable production onsite. In PHI’s formulation, the fundamental resilience of the enclosure is not lessened by adding renewables – as the renewable production is not in the service of making a building a “survivalist island” (my term) but instead is distributed to the grid to contribute to the survival of society.

Listening to the various talks on the subject it made me think, that as post-WWII American leadership remade our global economy with such ubiquitous drivers as the personal computer and the internet, today, it just may be the German energiewende (or energy transformation) that is leading the global shift from a fossil fuels based world economy to one based on renewable production. And that a post-fossil fuel world will be based on the interconnectivity of renewable power production, storage and its efficient use – not unlike the power our personal computers provide, not in isolation, but through their internet connection.

Benjamin Krick explains steps in new Certification Levels

But back to the specifics. PHI scientist Jessica Grove-Smith gave a detailed explanation of what’s under the hood of the new PER and the new certification levels. And Benjamin Krick walked through project examples showing challenges and opportunities in reaching the new Plus and Premium categories. (Stay-tuned for more information on another blog post dedicated to this subject.) Please come see Jessica Grove-Smith provide an in-person 60 minute presentation and Q & A on all this, June 11^th in New York City at the NYPH Passive House Conference.

All the new calculations are made with the new updated Passive House Planning Package (PHPP), Version 9 – an English language as well as an IP version will be available to US practitioners in the Fall of this year.

It’s the Global Community

Bronwyn Barry, Bjorn Kierulf, Dylan Lamar, Rainer Pfluger, Zuzana Kierulfova, Nick Grant

Meeting and learning from practitioners located around the world is a unique experience of the conference: a whole series of talks on fast paced developments in China, the challenges of building in Russia, new buildings in Spain and Italy, an embassy in Kinshasa, Congo, and so on. It shifts our perspective from our limits we face every day, to the possibilities everywhere – it was liberating.   Of course North America was also well represented, with presentations, in addition to Allen Gilliland mentioned above, by Matthew O’Malia of G-O Logic, Sam Hagerman of Hammer and Hand, and Adam Cohen of Passiv Science.

Harold Orr and Wolfgang Feist with attendees from North America

A special treat was meeting living legend Harold Orr, who received the fourth Passive House Pioneer Award.   Accepting the award in the closing plenary, Harold Orr gave a moving talk on the development of the Saskatchewan Conservation House – noting the dramatic effects and importance given to airtightness and thermal insulation he said, “Lots of insulation and airtightness, that’s what works.”

Finally, what seems to now be an established tradition, Saturday evening was the North American Passive House Network (NAPHN) Dinner – this year organized by NAPHN board member Andre Harrmann, a Leipzig native. With 120 attending, we unwound while meeting still more great people – from North America,

Bronwyn Barry, Chris Corson, Ken Levenson (author), Matthew O’Malia, Scott Kennedy, Dragos-Ionut Arnautu, Tim Lock

the UK, Latvia, Austria, Belgium, Slovenia, and so on – discussing, into the night, the conference proceedings and our ongoing work, in the pleasant amber glow of German beer.

Next Year

The 2016 International Conference will be held celebrating the 25 anniversary of the first Passive House, in Darmstadt, Germany, on April 22-23.   We hope to see you there.”

In addition to being a partner at 475 High Performance Building Supply, Ken Levenson is Co-President of the North American Passive House Network and President of New York Passive House.

On a recent visit to Jane Sanders’ EnerPHit Brooklyn brownstone retrofit, Floris took the opportunity to demonstrate the basics of Karsten tube testing. These tests are one of the ways to ensure the brick is good and ready for a high performance retrofit. Passing the test proves the brick is not too absorptive from wetting by precipitation. Conveniently, the building next door presented a great learning example of the evidence of freeze-thaw damage on masonry. For those interested in high performance masonry retrofits, learning to test brick with Karsten tubes is an essential part of the professional’s tool kit.

Larsen truss walls wrapped in Solitex make NJ’s 1st Passive House

Darren has chosen a cost-effective Larsen truss design, building the trusses on-site. OSB taped with Tescon Vana for airtightness inside, Solitex Mento Plus taped with Vana for the exterior air barrier, Applegate insulation all around, with Intus windows sealed with Tescon Vana and Tescon Profil.

We’re excited to see this project coming together and wish Bleu Nest the best.

Here’s Darren’s selection for airtightness:

• SOLITEX MENTO Plus for exterior airtightness and vapor open WRB, reinforced for dense pack insulation
• TESCON VANA for flat seams on the Solitex, OSB sheathing, and at window connections
• TESCON PROFIL for sealing windows, interior and exterior – best for making easy corners, with its 3-part release strip

Model your LAMILUX elements with BIM objects

Image: LAMILUX 3-D model 

LAMILUX is one of the first daylight system manufacturers to offer free BIM object services to create an effective process for mapping and simulating the architectural design, and actual construction of buildings in a virtual environment.

BIM (Building Information Model) is a new digital service which provides the real product appearance in 3-D models compatible with ArchiCAD and Revit CAD systems. Also, it offers integrated energy calculation engines that create energy balance schemes and gives the amount of energy that buildings will consume and CO² amounts generated.

Available BIM tools allow for more advanced calculations and simulations, like sunlight and shadows tracking, airflow, and sound simulations. In addition, these models provide information such as available dimensions, glazing options, U-values, and building material classes.

All the main LAMILUX components are available now in 3-D models. These include:

• CI System Rooflight Dome F100
• Flat window CI System Glass Element F100
• CI System Glass Element FE
• CI System Continuous Rooflight B
• Glass roof structure CI System Glass Architecture PR 60.

Go to the BIMobject site for free downloadable BIM objects from LAMILUX.

During my recent visit to Lunos in Berlin I was introduced to their newest high performance ventilation systems.  475 will introduce the following exciting solutions as soon as they are available:

• the Nexxt – a semi-central HRV with heat recovery efficiency of up to 90%, delivering ventilation up to 60CFM (winter 2015/16)
• RA 15-60 – exhaust fan for milder climates, delivering ventilation up to 35CFM (available now)
• ALD R160 – passive air inlet with filter and high sound absorbtion (available now)

All of these devices use the same 6″/160mm Lunos tubes that make installation of the e2 and eGO in exteriors walls efficient and easy to airseal.

Nexxt

This semi-central device uses a counter-flow heat exchanger, combining the advantages of a decentralized (ductless) HRV and a centralized system. It is very quiet and is attached with a single split tube (like the eGO uses) to the exterior. This means that for the fist time a single penetration in your airtight layer suffices to connect a HRV to the inside of the building.

The unit can be mounted in three different positions – recessed and ducted, flush (protruding just 2″, while still allowing duct connections), and surface mounted. This gives you full flexibility in both new construction and renovation for unit placement and exterior wall detailing.

The Nexxt can respond to input from temperature and relative humidity sensors, and optionally with a CO2 sensor as well.  This gives you the option to automatically run summer bypass on cool summer nights (or not) and/or activate high flow mode when occupancy in the room increases CO2 levels.

The unit draws as little as 5 watts on low flow and offers first class sound protection from exterior noise. Stay tuned for additional info when the product launches at the end of 2015.

RA 15-60

To complement the e2 system, and to offer efficient through-wall exhaust ventilation for climates where heat recovery from bathrooms/kitchens is not cost efficient, Lunos has introduced the RA 15-60. It fits in the same installation tube as the e2, but since this radial DC fan (also good for DC/PV powered houses) only takes up 1.5″ (37mm) of this tube, it allows you to fill the remainder of the tube with star-shaped sound absorbers. This can reduce the sound transmission from outside by more than 50dB, making it perform better than most triple pane glass. The fan itself has a sound pressure level of between 22-35dB, so it is primarily used for bathrooms and kitchens. Power consumption is as low as 0.04W/cubic meter/hr and minimum installation thickness is 6.7″ (170mm) if sound absorbing sets are desired.

The RA 15-60 is controlled by a Lunos universal controller – which now also features time lag add on. This module enables you to extend the run time to 0, 6, 15 or 3o minutes beyond a ventilation trigger (light in bath turned on/high humidity event).

Additionally this timing module can also be programmed to exhaust 15 minutes every 2 hours or 30 minutes every 4 hours – making this an ideal plug and play device for controlled exhaust ventilation in mild climates. This module will be available at the end of summer 2015 and anticipated list price is $39.

ALD R160

This passive air-inlet is a non-powered hole in your wall – albeit a bit more sophisticated than just a simple hole. Its benefits include:

• Controls airflow with a ventilation rate at 8Pa pressure (equal to the result of eGO or RA 15-60 exhaust operation)
• Similar sound attenuating properties that are also found in the RA 15-60 (up to 55dB while in operation)
• Includes an automated pressure sensitive wind damper, which prevents over-ventilation from gusts/storms
• Includes a G3 filter – for filtered fresh air

Exterior covers

We’ve received requests for different (non-round) exterior grilles and will offer two new options in Fall 2015:

1. Hidden exterior grilles (Lunotherm) that integrate very well into EIFS facades (including GUTEX Thermowall system). They allow you to avoid visible ventilation facade penetrations in your building, while not compromising airflow or insulation levels. And they work with standard 6″ diameter Lunos tubes. Prices starting at approx. $139 per unit.

2. Square exterior grilles 1/HWE (black) and 1/HAZ (gray) with an added benefit of an additional exterior noise reduction of 6dB.

We are excited to offer these new products and look forward to seeing them implemented in high performance construction projects in the US in the near future.

Any questions, please contact us at 800-995-6329 or info@foursevenfive.com

475’s first ebook, High Performance Historic Masonry Retrofits, has been hugely successful. And we thank you for the support and feedback we’ve gotten. In light of that, we’ve been eagerly plowing away at book #2, and are proud to announce the beta version of our follow-up: High Performance I-Joist Assemblies.

This will be the first of several we plan to release for new construction timber frame buildings. Just as before, this book lays out all the details necessary for optimizing building airtightness, vapor control, and continuous insulation – all foam free.

The I-Joist model has become a favorite among those who use Pro Clima airtight systems in North America. It’s been tested in the real world in some of the harshest environments, and proves to be a robust, simple, and cost-effective strategy for building airtight, vapor-open and foam free.

• Download High Performance I-Joist Assemblies now
• Pre-Order your hardcopy version, to be released in August

OR find all of the available books in our growing library in the Quality Control section.

Although we can’t yet release the focus of our next ebook, we do plan on creating an ebook for each one of the downloadable CAD Details. So, much more on the way. Please don’t hesitate: we want your feedback. We want to hear how you use these books and details, and what experiences you’ve had implementing them in your projects.

This spring we said “Passive House Poised To Go Big.” Now we’re saying “Passive House Is Going Big.”

On June 16th, Cornell Tech held a groundbreaking ceremony on Roosevelt Island. While the event took place to announce Bloomberg Philanthropies $100Mil gift to the new campus, the “BOOM!” heard round the low-energy/high-performance world was news that the campus will have the world’s tallest Passive House. Mayor Bill de Blasio, Cornell President David Skorton, and David Kramer, Principal of the Hudson companies, all spoke at length about the importance of making this building a Passive House. We whittled the 1 hour plus ceremonial speeches down to the 4 minutes plus that will interest you energy-minded folk. (Note: Mayor de Blasio’s thanking “the Mayor” is referencing former NYC Mayor Bloomberg, seated just to his left).

Developed by the Hudson Companies in partnership with Related Companies, it was designed by New York City-based Handel Architects, with engineers BuroHappold, Passive House consultants Steven Winter Associates and Passive House Institute certifying organization, Passive House Academy. The high-rise will also be the tallest building on Cornell Tech’s campus.  Press reports can be found on the NYTimes and Green Building Advisor.

Just days before this groundbreaking speech, Mayor de Blasio was awarded the first annual New York Passive House Hero Award at the well-attended NY15 Passive House Conference and Expo at the Metropolitan Pavilion on June 11. If Passive House can make it in New York, it can make it anywhere. And the world’s tallest Passive House will be arriving on Roosevelt Island in only 2 years.

In the spirit of 1776, 475 High Performance Building Supply is proud to reprint an update to our Declaration of Independence from Foam Plastic Insulation, first published for July 4th 2013 (Treehugger).  Enjoy:

In BROOKLYN, NY, July 4th, 2015.

A DECLARATION.

WHEN in the course of constructing and renovating buildings, it becomes necessary for architects, consultants and builders to stop using materials and methods which have defined high-performance building in our time, and determine to set a new course separate and free from foam plastic insulation and the chemical companies that push it, the consideration of others requires that they declare the causes for this separation.

WE hold these truths to be self-evident, that building and renovating should be done with certain unalienable duties:  that among these are to promote the health and well being of construction workers and building occupants, while protecting our natural resources and biosphere, providing happiness today and for the generations to come.  That to secure these duties, choices are made by practitioners, deriving their powers from the best current science available.   That when any form of corporate domination becomes destructive of these ends it is the right of practitioners to alter their choices and institute new methods, laying a new foundation on such principles and organizing its means, as to them shall seem most likely to effect their Safety and Happiness.  Prudence dictates that means and methods long established should not be changed for light and transient causes; and accordingly all experience has shown that we are more disposed to suffer while evils are sufferable, than to right them.  But when a long train of abuses, pursuing invariably the same Objective evinces a design to hold building industry practitioners captive to their absolute deceptions, it is the practitioners right, it is their duty, to throw off such materials, means and methods, and provide new Guards for their future security.  Such has been the patient sufferance of practitioners, building occupants and our biosphere.  The history of the present foam plastic insulation industry, is a history of repeated injuries and deceptions, all having in direct object the establishment of tyranny over the building industry.   To prove this, let Facts be submitted to a candid world.

1.  It is made primarily from isocyanate, formed from methylene diphenyl diisocyanate (MDI).  MDI is manufactured with benzene, chlorine compounds and formaldehyde leading to release of dioxins and furans –  bioaccumulative toxicants, carcinogens and endocrine disruptors.  MDI is also a known allergen and sensitizing toxicant.  See here.
2. Its catalyst is often an amine compound and can induce a wide range of debilitating effects, from  the skin to the nervous system.  See here.
3. The hydrocarbon blowing agents used for closed-cell foam are a potent greenhouse gas and in many cases may cause more global warming than it can ever prevent.  See here. (GreenBuilding.com subscription)
4. Flame retardants in it are made from halogenated organic compounds with chlorine or bromine bonded to carbon and are persistent bioaccumulative toxins which can be found worldwide in humans, wildlife and the environment.  See here (pdf).
5. Its flame retardants don’t work, consequently we are poisoning our environment with them for the illusion of fire protection.  See here.
6. It regularly greenwashes with claims of soy and other natural ingredients in the polyol – declining to mention the toxicity of the dominant and unaltered MDI. See here.
7. It can produce unhealthy off-gassing, and forming the basis for multi-state lawsuits.
8. It has forbidden its Governors to pass Laws of immediate and pressing importance.  See here.
9. It is petroleum based and a fire accelerant, feeding fires, reducing effective firefighting response times, causing more damage, injuries and death.  See here and here.
10. Its improper installation has started fires with deadly consequences.  See here.
11. That burning it produces toxic pollution, dangerous to occupants,  first responders, and the surrounding environment.  See here.
12. It has over stated insulating values.  Given the declining insulating value over time and often at colder temperatures of closed-cell foam, it has not provided accurate data on actual insulating values under conditions practitioners reasonably expect.  See here.
13. It has undermined the resilience of assemblies:
    1. It is hygrophobic and doesn’t actively help manage moisture intrusion.
    2. It excessively shrinks and expands putting undue stress on connections.  See here.
    3. It is inflexible and prone to cracking.
    4. It provides weak and unpredictable air control.
    5. It can be a counterproductive vapor retarder/barrier, creating wet conditions at sheathing.  See pages 11& 12 of pdf here.
14. Its on-site manufacture in spray form is hypersensitive, and regularly results in substandard and virtually unrepairable messes while gassing the building and environment with toxins.

WE therefore declare, appealing to our conscience as stewards for building contractors and occupants today, first responders, and future generations, That architects, consultants and builders ought to be Free of chemical company disinformation and the dominance of foam plastic insulation, with full power to make foam-free assemblies and foam-free deep energy retrofits that are more resilient, energy efficient and non-toxic.   That as Free and Independent practitioners, they have full power to Act in all manners to secure their sacred duties.

 Related Posts:

• Foam-Free Wall Assembly Guidelines by Climate Zone
• Foam-Free DER: Series Introduction
• Foam-Free DER: Roof Assemblies
• Foam-Free DER: Wall & Foundation Assemblies
• How to install dense-pack cellulose with Intello Plus airtight membrane
• 475 Presentation:  Foam Free High Performance Building Enclosures
• VOC free Air Sealing with Pro Clima

You have a choice of air sealing tapes, so why choose Pro Clima?  With five solid reasons making the case, it’s easy to say Pro Clima tape is the best:

Reason #1: Pro Clima Tapes Have The Best Stick

The pressure activated adhesion of Pro Clima’s solid acrylic tapes are second to none, as proven by independent WTF testing. Key to the unparalleled sticking power of Pro Clima tapes is the science of the acrylic adhesive, where no solvents are present and the adhesion doesn’t rely – like leading competitors – on a liquid formulation that results in “stickiness” but produces a bond that can slip and slide out of control. The solid acrylic adhesive is temperature and moisture tolerant and the backing is a polypropylene (PP) form-fitting fabric that is easy to apply. It just sticks best.

Reason #2: Pro Clima Tapes Last Longest

Pro Clima’s solid acrylic adhesive was born in the demanding aerospace industry decades ago. Today, Pro Clima tapes are standing the test of time – installed on job sites for over two decades as well as undergoing rigorous unparalleled accelerated age testing – recently completing 100 years without degradation to its bonding effectiveness.  100 years! It sticks longer than many buildings are expected to stand. 

Reason #3: Pro Clima Tapes Cost Less

Tescon Vana, the premier Pro Clima workhorse tape, starts at just 30 cents per linear foot. Compared to any tape of similar quality, it costs less. Pro Clima tape is a better tape at a better price.

CONTEGA EXO: exterior vapor open window airsealing tape with three adhesive strips.

Reason #4: Specialized Tapes for Specialized Needs

Tapes make connections and the types and configurations of connections are almost limitless. As a high-performance builder you have specialized needs to make sure connections are made to last. So while 99% of connections may be handled with just a few standard Pro Clima tapes (Tescon Vana, Tescon Profil and Extoseal Encors), there is a uniquely exhaustive selection of tapes to meet virtually every need: split back tapes, super-wide tapes, tapes with multiple adhesive strips, tape with fleece backing, vapor retarding tape, vapor open tape suitable for masonry, tape for wire or pipe penetrations, double-sided self-sealing exterior tape and double sided interior tape. If you have a specialized  taping need, Pro Clima can give you a specialized answer tailored to your needs. No compromises!

Reason #5: Not Just for Air Tightness

America’s long love affair with duct tape, as the one tool to answer an inexhaustible number of needs has met its match with Pro Clima tape. Pro Clima tapes are not only answering the call to provide building air-tightness but also to mend auto bodies, patch clothing, and mend furniture upholstery – just to name a few. With a roll of Pro Clima tape you can tackle almost anything.

So there you have it – five reasons to rest assured that Pro Clima tapes are the best. Get the tape that sticks better, longer, for less cost, that does the job you want, as well as the job you hadn’t even considered yet.

You may have seen us refer a Pro Clima tape or adhesive as ‘permanently airtight’. It’s important we be clear about we mean, because it’s one of the details that sets Pro Clima tapes apart from the rest of the pack. Having an airtight layer that endures the life of a building can depend on design decisions, such as integrating the airtight layer into the assembly, planning to include a service cavity, or choosing a caulk that flexes rather than dries stiff, which leads to cracking. In the end, regardless of the design, the longevity of the materials themselves is of primary concern. Our definition of “permanent airtightness” boils down to this:

Airtight materials should be airtight for longer than the building is expected to last.

And we don’t mean 30-40 year barely-code-legal homes. We mean high performance buildings: 100+ years.

Accelerated Aging Tests

Tescon Vana has been independently verified by the University of Kassel in central Germany using accelerated aging tests. What this means is that the material is exposed to extreme conditions in a controlled environment that mimic the effects of time, air, water, exposure, etc. The lab stored Tescon Vana at a temperature of 150 °F with 80 % relative humidity, sustaining it in a condition at the far extreme of what is possible for brief periods in real construction. The tape was kept this way for 700 days, about 2 years, which shows Tescon Vana’s adhesion will perform reliably for 100+ years. It’s important to note that the test parameters at University of Kassel were developed to determine ”quality assurance for adhesive-based joint technology in airtightness layers” – something you will uniquely find in the land of Passive House.

Real-World Testing

Floris applies Tescon INVIS tape. Tescon Vana, Tescon INVIS, and Tescon Profil tapes the same tape, differing only by color, and type of release backing.

Lab tests are correct much of the time, but longterm judgements get based on real-world use and testing. We’ve been using Tescon Vana in the United States since 2011, and Pro Clima developed the technology and adhesives for Tescon Vana in the early 1990’s. Field tests from that time are holding strong 20 years on. The Pro Clima airtightness system has proven itself many times over, winning the Stiftung Warentest (The German equivalent of US Consumer Reports) in 2012.  Solid acrylic adhesive tapes do not contain solvents – meaning no part of adhesive is water soluble. Adhesion is pressure activated, to form a strong grip at the molecular level – assuring a long lasting, durable connection between the tape and the substrate. Our real-world experience, combined with our knowledge of the material, have provided us with an unwavering confidence that this tape is the best. That’s why we choose to sell it, and that’s why we use it in our own project. Want to prove it on your own? Get a free sample and test it yourself.

Longevity = Sustainability

We know there is no silver bullet to end the climate crisis. It’s a billion decisions made around the world to save energy and greenhouse gas emissions. One commonality among those decisions, is to stick with materials that last, rather than the ones you throw out in a few years. But even if you don’t buy the environmental benefit, think of it this way: you want a hammer that will last as long as your career, not as long as  your current project. And you want nails that hold the wood together as long as the wood is standing, not rust and crumble. Pick the tool that you can rely on.

Press a strip of Tescon Vana onto the plywood of new building today and you can expect it to stay airtight until 2115. We will all be cyborgs, with embedded and wearable biosensors that track physiologic metrics that are guided by one’s genes and environment, you’ll be worried about the housing market on the Mars colony, and Tescon Vana will still be airtight. That’s what we mean by permanently airtight.

There’s a growing demand for high performance roof retrofits. For many homes it can be most practical and economical to improve the airtightness and insulation from the interior. Often the homeowners also don’t want to leave their homes during the retrofit work. That takes spray foam off the table, since chemical exposure to spray foam during installation is a serious health risk. (Those haz-mat suits and gas masks aren’t just for show).

Dolphin Insulation, a cellulose insulation contractor based in Littleton MA, offers interior roof retrofits that are both high performance and foam-free. Over the years they’e refined their approach, and now provide unvented roof retrofits that exceed code requirements for insulation and vapor control. They do this using dense-pack cellulose along with Intello Plus airtight, smart vapor retarding membrane.

Beyond Roof Weatherization

Dolphin is pushing the industry far beyond conventional weatherization and into Deep Energy Retrofit levels of performance. By using cellulose insulation, they also complete the work without danger to themselves or the building occupants – and with minimal inconvenience – so life can go on largely without disruption in the living areas below.

These days Dolphin takes on a lot of “hot roof” retrofit projects that aim for minimum R-40 insulation. By including the attic in the conditioned space, it becomes useful for storage and HVAC. For HVAC systems in particular it’s a win-win scenario. The airtight and super-insulated enclosure makes an HVAC system more efficient, but also reduces heating and cooling demand so the homeowner can save money on a downsized system. David Posluszny, Dolphin’s Energy Engineer (recently featured in Home Energy Magazine’s “Thirty under 30“), notes: “We worked to an R-40 because [the owner] was having an air conditioner installed in the attic.  However, the house has existing baseboards for heating.  If the HVAC was going to be a furnace in the attic we prefer going to an R-60.”

They start by furring inward from the 2×6 rafters with 2x4s to create a thermally broken “double roof”.  They also fur in the gable end walls. Then they install Intello Plus by stapling to the inside of the studs. They tape horizontal and vertical seams with Tescon Vana 75 (3″) or Vana 100 (4″) solid acrylic tape for robust airtight connections. Whenever possible they use double-wide (~10′) Intello Plus to keep horizontal connections down to a minimum. For this project they used 10′ wide membrane over the gable and 5′ wide membrane for the remaining areas on each side down to the eaves.

They follow with  vertical plywood strapping over the rafters and studs. This strapping ensures that they avoid staple tear-outs when dense-packing to levels above the industry standard 3.5 pounds per cubic foot. For maximum strength they also position vertical taped seams to coincide with strapping. (Note from 475: we typically recommend horizontal strapping perpendicular to studs/rafters. But in cases where higher density is desired, vertical strapping can help prevent staple blow-outs.)

Beyond Typical Dense-packing

Once the strapping is in place, they like to dense-pack to as much as 4.5 pounds per cubic foot. At this density, the Intello feels quite hard (for comparison, at 3.5 psf the density is often likened to a “firm mattress”). David notes: “It is a great product. Our crews like using it because of the strength.  Dolphin Insulation packs cellulose to 4.5 pounds per cubic foot. We have tried several products on the market to contain this density, but all seemed to pull out, give way, or stretch too much. The Intello Plus stands up to the pressures.”

After several projects, Dolphin has optimized his dense-packing approach. They prefer to allow the bays to “communicate” and pre-fill all of them.  Then they go back and dense-pack one at a time.  The pre-filling in the adjoining bays serves the function of separating the bays.  David: “With our machines (extremely powerful and expensive) we find the best results with this method.”

They cut one opening in each bay for blowing in. After the bays are packed, they patch the blow holes with 6″ squares cut from Tescon Vana 150. David adds: “Of course there are plenty of spots thicker where the Intello Plus bulges out a bit with the massive cellulose.  Those areas have higher R-values, but we don’t count those [in the R-40 total].”

With Intello Plus, Dolphin achieves high performance insulation, airtightness and smart vapor control in essentially one step.

Dolphin also makes improvements at the wall connections. They extend Intello Plus all the way to the wall airtight layer with resilient stapled and taped airtight connections. In practice, it’s challenging to get those connections perfect. By dense-packing into the attic joist bays – a physically demanding job (see photo) – they balance the air and vapor control benefits of both Intello Plus and hygroscopic cellulose at that important transition.

Vapor Variability = Venting Not Required

The Dolphin team notes, “there is no venting in the assembly, and we don’t need any thanks to the INTELLO Plus.” 475 High Performance Building Supply best practice recommendation is to vent cathedral roof assemblies. But there are times when roof venting is either impossible or impractical (ie the house has a new roof and there is plenty of attic space to interior insulate). In those cases, INTELLO Plus provides the robust airtightness and vapor control needed to keep moisture levels safe – because of its best-in-the-industry vapor variable properties. This has been documented in our project spotlight on the recent Middlesex VT Passive House, which takes full advantege of INTELLO Plus for its unvented and super-insulated flat roof. In combination with TESCON Vana tape, with 100 year age-tested performance, this resilient system can be expected to far outlast any foam-based solutions while providing more reliable and predictable air and vapor control.

Most building codes or inspectors do not fully understand the safety that smart vapor control can bring. The route to choose in those cases, is to work with 475 technical team and convince them that:

1. INTELLO airtightness verified with a blowerdoor test is equal or better (certainly more durable) than foam inboard of the sheathing.
2. INTELLO’s vapor variable properties allow inward drying of unforeseen moisture (caused by rain, construction moisture, or new air leaks from occupants’ puncture holes). With INTELLO these can dry out in summer – something that is not possible with foam. By request, we can provide a worst case WUFI Pro study for you location to press the point.

For best practice interior roof retrofits, we like to advocate a hybrid approach that combines INTELLO Plus at the interior with back-venting at the exterior – this can be done with or without a new roof but we acknowledge does take much more effort – and with INTELLO on the interior in most cases is not required.

Further Discussion

For a detailed discussion of retrofit approaches, see our blog post Foam-Free DER: Roof Assemblies, get out free downloadable CAD details here as well see Alex Wilson’s interior roof retrofit case study: Can’t vent at valleys and dormers? Use a smart vapor retarder (not foam).

We can dramatically reduce residential energy use and help solve the climate crisis – with retrofits like this one multiplied by 10 million across America

http://energy.gov/eere/wipo/what-weatherization

http://www.greenbuildingadvisor.com/blogs/dept/musings/insulating-low-slope-residential-roofs

http://www.dolphin-insulation.com/

One of our main goals at 475 is to stimulate conversation on high performance building practices, philosophies, products, and people.  It’s what we feel is required to drive the market forward, and what both we ourselves and you as professionals are genuinely interested in hearing.  We try to keep our content unobtrusive, delivering to our followers no more than one email a month, while maintaining an active social media presence to keep you informed about some of the projects, events, and topics most interesting to us, but what we don’t always get across are some of the conversations that happen with our customers on a day-to-day basis.  We receive a constant flow of questions via email, phone, online chat, and in person on job sites and at our Brooklyn, NY headquarters.  We also want the rest of our network and the high performance building community to be able to benefit from the careful answers and advice we give our customers through these channels.

That’s why this week we’re starting a new blog series called “Question of the Week”.  Instead of overloading you with a cornucopia of conversations and excessive information, we’re going to pick our most interesting, new, and unique question of the week – and share feedback from our team as well as from people whose opinions we respect.  We hope this will stimulate conversation, so we would love our readers to share their insight.  And of course, there’s no such thing as a stupid question, so you can always feel comfortable continuing to send your other questions our way.

Get started with our fist question here.

This week’s question:

A HERS rater’s quest to understand how to model the Lunos e2 and eGO units in REM/rate software.

“Hi, I’m a HERS Rater and need to model Lunos e2 and eGo units in REM/rate software for a HERS Rating. Can you tell me what values should be used for the sensible recovery efficiency % and total recovery efficiency % inputs?  I understand these units are not yet listed on HVI, so I can’t use that data.  Thanks.”

…here’s our response:

Very good question. While  the unit is not HVI certified, it does have the German certification (DiBT), and we can recommend that these published values be used.   The German DiBT tested efficiency of 90.6% average can be used as ASE in REM/Rate. The DiBT is part of the federal government of Germany and a fully independent 3rd party regulatory organization.

 “I’m tending to be conservative and use the design temperature end of the temp/efficiency curve I received in German and give it an 80%, with power consumption as  stated in the literature.  Part of this is for sizing mechanicals design temperature is used, and part is the fans are pretty weak.  Floris has warned us not to measure airflow on a windy day when there is not much margin between the specified performance and the minimum required for the Program.  I did check with my HERS QA Designee, and there is no formal process for doing this other than resorting to manufacturer’s data sheets and properly applying good judgement and being conservative.”

So, HERS raters, there you have it.  Some unique insight on how to model the Lunos system in your REM/rate software.  At such impressive efficiency in terms of energy consumption and heat recovery, Lunos fans are a high-quality, flexible, eloquent and effective solution, providing fresh clean air and a healthier indoor environment for your next project.  Purchase them here or watch our video intro to the Lunos heat recovery system.

Already used the Lunos and looking for what’s next?  Stay tuned for the appropriately-named Nexxt from Lunos, a semi-central HRV requiring only one exterior wall penetration, but providing the ability to duct to additional fans, or call us to ask about the Lunotherm, an exterior insulation system to direct the flow of air out a window opening instead of through an exterior grill.

With vapor variable materials, your mileage and protection will vary

Intelligent membranes, or smart vapor retarders can help prevent condensation in enclosure assemblies (walls and roofs) in winter, while allowing inward diffusion in summer. This transformation is an important characteristic that assures an insulated assembly’s safety – ie increase it’s drying reserves so it can cope with (un)forseen moisture entry into —- and out of the assembly. The INTELLO primer explains this.   But how and when the material goes from being a class II vapor retarder (far below 1 perm and almost a class I vapor retarder) to a vapor permeable material deserves a more detailed look.

The ICC building codes require a class I or II vapor retarder on the inside of insulated assemblies (IRC 1405.3 and IBC R702.7) in Climate Zones 5, 6, 7, 8 and Marine 4. This is to prevent warm and more humid interior air from moving through the insulation and condensing on the cold “condensing surface”.  Typically the condensing surface will be the exterior plywood or OSB sheathing. The vapor drive is outward in the winter, so a interior vapor retarder will be warm, so no condensation will form it while preventing the humidity from reaching a cold condensing surfaces. But the downside of having a material that is below 1 perm at that location – interior of the insulation –  is that once the vapor drive reverses in summer, the vapor drive is now inwards (more humid outside than inside) and a low perm material will not let any humidity through – effectively damming it.  You can see that in the image below, where a poly-ethylene vapor barrier is showing the humidity trying to push inward -but since the material is vapor closed – the humidity now condenses on the inside.

It would be best of course, if the material in winter is a class I or II material when the vapor drive is outward, and when this drive is reversed in summer – that it is as open as possible. Hence the need to have smart or vapor variable retarders was recognized – and as a consequence, INTELLO was developed by Pro Clima.  INTELLO is a smart vapor retarder with the highest level of vapor variability available on the market, and just as important, it become permeable at the right time – not too early, not too late – more about that below.

How is a material vapor variable?

To understand how (airtight) materials have different vapor permanence at different relative humidity let’s take the example of wood sheathing.  A 5/8″ thick piece of OSB is a class II vapor retarder at 30% relative humidity. It becomes more vapor open if the relative humidity of their surroundings get higher. This can be understood as the wood taking up this humidity and consequently this damp wood, becomes more vapor permeable – absorbing humidity on one side, transferring it to the other side and releasing it there.  You can see that OSB gets a bit more permeable (2 to 4 perms depending on the testing lab) after it goes over 60% RH and 80%RH, but it will also start to rot or mold at that point. Since OSB is pretty retarding  to start, it can be a suitable vapor retarder to use on the interior of the assembly – but then you will have to make sure that the assembly can dry outwards from the OSB to the outside, ie it should only have materials that are more vapor open than OSB on the exterior of it. This goes back to the 1:5 rule of thumb perm ratio that we have discussed before and is a ratio that the DOE, German DIN 4108-3 regulations, and Robert Riversong’s quote on GBA, 3rd paragraph, refer too.  This 1:5 rule shows that for the most safe assembly, your exterior should at least be 5 times more permeable in winter then your interior vapor retarder.

OSB that has seen different moisture content

Source: Ecological Building Systems – ecologicalbuildingsystems.com

There are some considerations with wood sheathing and vapor permeance and their airtightness, which will influence their suitability as vapor retarder and airbarrier:

1. WUFI Pro notes in the material data: “Since wood and wood-based products tend to swell and shrink, their material properties may depend on the current as well as preceding moisture contents. The applicability of WUFI has to be decided on a case-by-case basis”.
2. It has been demonstrated in Europe and in the USA that OSB is not reliably airtight. We have gotten at least 2 reports of this happening in the USA. Again, this probably differs from brand to brand, plant to plant and glues/species used. If a material is not manufactured to meet air-tightness  below 0.004CFM/sf, then using it as an airbarrier is questionable. See photo at right above that shows OSB leaking during a blowerdoor test. We have not seen this happening to date with Plywood.
3. The vapor profile of wood sheathing varies with thickness, production plant (amount and type of glue used), wood species in boards, the list is endless. So consider this, for instance Dupont has had ZIP system panels tested for wet and dry cup permeability – which showed it remained below 1 perm in both cases  (Page 3 of this Dupont publication).

Consequently, we can see in the graph below the US perms of different materials at different humidities. Hardwood is too open to be a class II vapor retarder, and it would take a lot of tape to make an airbarrier out of sawn lumber. It also shows that OSB is not very variable, it goes from a low class I to a low class II material – and there are even some OSB’s that have a fixed perm rate in WUFI, in that case solely the moisture distribution (sorption/absoprtion) will account for the moisture transport through the material when those are selected. Plywood becomes a bit more permeable above 50%, but does not go above 9 perms in 5/8″ thickness.   Of course the exact numbers are also dependent on sheathing thickness, glues, the production plant, the age, and moisture cycling the sheathing has had.

The curve matters, when should smart vapor retarders open up.

Buildings experience high and low humidity on the interior during construction and occupation. Pro Clima recommends that heightened moisture levels during construction should be avoid as much as possible, but we realize that is not always possible. Furthermore there are spaces in the house that have higher interior humidity such as kitchens and bathrooms. To prevent humidity from rushing into the assembly during those times. Pro Clima has established the 70%/2.2 perm rule for the construction phase and the 60%/1.64 perm rule for completed and occupied spaces.

Occupied increased humidity, the 60/1.64 rule

During regular use of the spaces, rooms like bathrooms and kitchens experience higher interior humidity, and when heavily used can result in relative humidity at the vapor retarder of 60%. If materials are less then 1.64 perms at that condition, these higher humidities are sufficiently retarded during these daily periods of higher humidity. If an airbarrier has a vapor permeance that exceeds this 1.64 level, to much moisture can enter the insulation. This is shown in the graph below where you can see that for instance polyamid/nylon of Membrain far exceeds this with >3 perms.

Construction humidity: the 70/2.2 rule

Large amounts of humidity is created during construction, especially when you are pouring concrete, tiling, plastering, compounding sheetrock etc. etc. This can cause very high levels of interior humidity, both in summer and winter time. Even while controlling the levels with dehumidification and venting, you can have periods of greatly increased relative humidity. They can cause the vapor retarder/airbarrier to experience RH as high as 70%. To make sure this humidity does not end up in the insulated assembly and cause mold and decay, the maximum perm rating  should be 2.2 perms. It is then still tight enough to keep the majority of this humidity, from this one-time-event, out of the assembly. ProClima’s INTELLO easily complies with this requirement with a vapor permeance of 1.6 perms.

The best curve, opens up after 70%

Since issues in walls (rust, rot, mold) occur at 80% RH and above, it is important that after relative humidity exceeds 70%, that vapor variable retarders upon up as fast and as much as possible to facilitate inward drying in summer months. If a vapor retarder has a fixed permeability, like poly-ethelene (below 0.1perm) or Siga Majpell at 0.68perm – than neither unforeseen moisture can dry out rapidly in summer, nor can you be sure that if you’re air-condition the building, that you won’t get issues with inward vapor drive condensing on such fixed vapor retarders/barriers in humid summer weather.

INTELLO has the best in class smart vapor retarding profile, which a permeance that varies by more than a factor 100, twice the permeance spread compared to the next in class material. ProClima’s smart retarder is very vapor retarding in dryer winter situation (0.13 perms compared to Membraine’s 0.75 perms), while becoming vapor permeable at over 13 perms in summer. This features allow you both to construct:

• highly insulated assemblies in practically any climate with an exterior vapor retarder such as OSB sheathing, ZIP system, flatroofs, unvented asphalt roofs, etc. (We do complimentary  WUFI study in certain cases to make sure that the drying reserves are sufficient and/or when building inspectors need to be convinced (since the code does not understand vapor variability)
• best practice, vented roofs and walls in mixed and humid climates, that are foam free and protected from both summer and winter time condensation concerns.

Welcome to the second installment of our Question of the Week Blog Series!

**Please note that in republishing our question of the week, we sometimes edit the text of the original question and response in order to provide additional clarity to the issue.**

For this week’s Question of the Week, we bring you a question from an architect/designer looking for an effective solution for his wall design:

“Hello,

I am developing a rain screen wall design consisting of a rain screen held in place by a knight wall system, mineral wool insulation, then an air & water barrier adhered to exterior sheathing. We are concerned about rain/ice getting into the mineral wool and are looking for a water resistive barrier to install between the mineral wool and rain screen such as this product: http://www.cosella-dorken.com/bvf-ca-en/products/wall_ext/wrb_open-joint/products/fassade-s.php . Do you have any additional product recommendations? We would not expect to have any noticeable gaps in the rain screen.”

Our response:

“Dear J,

We recommend using SOLITEX FRONTA QUATTRO for this application – it can be taped with Pro Clima’s TESCON INVIS – an all-black airsealing tape with very similar properties to our all-around TESCON VANA waterproof airsealing tape.  We recommend TESCON INVIS in conjunction with SOLITEX FRONTA QUATTRO because of the extra UV stability added to both the membrane and tape, as well as the ability of the all-black system to hide behind an open-joint rainscreen.

When comparing to DELTA’s Fassade-S, FRONTA QUATTRO is easier to  put up, not super thick like the CORSELLA product, and it’s more waterproof, while being actively vapor open.  We can additionally recommend special techniques to put it over mineral wool boards – secure the membrane in place with 1″ roofing nails under the overlaps, and be sure to not leave any penetrations exposed.  It’s also important to note that Fassade-S is not an airbarrier – it is rated at .9L/s*m2 – it needs to be below .02L/s*m2 for ICC-AC38 compliance.  SOLITEX has been tested to be 100x tighter than that.”

Why are these differences important?

Certainly, both products have extra UV stability and are vapor open, which are important components of an open-joint rainscreen assembly.  But avoiding windwashing of the insulation is an important reason to have airtightness on the exterior of the assembly, even if there is an additional inboard airbarrier such as INTELLO.  At 32lbs, FRONTA QUATTRO is lighter than Fassade-S, so getting it up on the wall is noticeably easier.  At $0.49/sq ft., you get better quality at a better price, along with a tape whose acrylic adhesive sticks better than anything else out there.

Honorable Mention:

This week we launched our monthly newsletter, and as with all of our newsletters, we tried to feature some topics and projects that would not only be of interest to you, but would also stimulate debate. We had some great activity on our blog this week specifically from our post about unvented foam-free roof retrofits, but since you already have access to the conversation that ensued, we’ll simply give our first commenter’s question – “What’s the track record of this approach?” – an honorable mention this week. Thanks to the inspector, architects, and builders who contributed to the discussion.

Have a great weekend!

Question of the Week – Part 3.

This week, we bring you a question from an engineer in New Hampshire.

The question:

“I am thinking of using 3” “roxul comfortboard is” on the exterior of an older house.  I would like a detail for installing an “outie” window, the window will be an Anderson new construction window with wide flanges to accept Anderson snap on trim surround.  Typically a window box is built with ¾” plywood, but in this case the window frame needs to be at least 3” wide to accept the flange, I would prefer not to use a double 2x to accomplish this since it would create a sizeable thermal break in the system.”

Our response:

Hi A,

“Good to talk with you about your retrofit window details. As discussed, we’d be happy to take a look at your drawings, including wall and roof assembly details. We regularly make project recommendations using the Pro Clima airtight systems.

Regarding your window question, the 3″ wide flange makes things a bit tricky, especially if you’re determined to avoid thermal bridging. As we discussed, you can still build a 3/4″ plywood box, but screw the flanges into CompaCFoam. One could make a strong argument for this approach by noting that, in addition to lowering heat loss, the CompaCFoam will prolong the life of the windows by preventing condensation damage.”

CompaCFoam is a vapor-permeable, high-density EPS foam insulation that can provide structural support and insulation for windows.  For more about CompaCFoam, check it out here.  We hope to update you soon with one of the earlier projects to use the material in the US – the SURE House Solar Decathalon project by the Stevens Institute of Technology in Hoboken, NJ.

Don’t forget to check out the other questions in our series:

Introducing Question of the Week

July 10, 2015 – Lunos and REM/Rate

July 17, 2015 – Open Joint Rainscreens – A Comparison of Pro Clima and Corsella Dorkin

Have a great weekend all.

**Please note that in republishing our question of the week, we sometimes edit the text of the original question and response in order to provide additional clarity to the issue.**

In 2009 New York City instituted mandatory energy use reporting for all buildings over 50,000 sf – initiating a potential windfall of useful information to better understand what our big buildings are actually doing. And if we could understand what is actually being consumed we’d have a better shot at making substantial performance improvements.   While compliance is an issue, the really tricky thing is the understanding part. A mountain of data in an excel spreadsheet doesn’t automatically translate to understanding. Enter NYC’s Urban Green Council (UGC) and their trailblazing website Metered New York.

NY Times Building Entry

Metered New York provides a user interface that lets you find the numbers, and better still, to compare them from one building to another. Sure the Chrysler Building and Empire State buildings competed for height supremacy in the Great Depression, but which one is winning the carbon battle today? Despite the much publicized recent efforts to improve the Empire State Building’s performance, the Chrysler Building wins! The Chrysler Building has a Source EUI (Energy Use Intensity) of 171.3 kBTU/SF*yr versus 180.5 for the Empire State Building. While the much touted New York Times building clocks in a reported Source EUI of 276 or a site EUI of 134.8.

This last data set raises some questions as to just what data is being reported to the city. While UGC has done a great job flagging questionable reporting, this 2013 article notes that scientists from Lawrence Berkeley National Laboratory (LBNL) measured the NY Times Building site EUI at 29, an almost 5-fold difference.

More sobering still is that even if LBNL is correct it is still more than double the site EUI of approximately 13 that Passive House requires.

What is energy use intensity? source: energystar.gov

We encourage everyone in New York City to find their buildings or the building they admire, see what the reported energy use is, and compare. Compare the buildings to each other and compare them with where we need to go. Too many buildings have a Source EUI of over 100 and even over 200 and 300. The new Cooper Union LEED Platinum Architecture Building (41 Cooper Square) clocks in at a Source EUI of 396! A platinum plated climate catastrophe. We believe it.

Source EUI for Passive House is just 38. Check out the numbers and let’s push toward Passive House.

We know that the importance of airtightness is second only to keeping the rain out.  This is because airtightness greatly effects indoor air quality, thermal comfort, and energy efficiency – while protecting the enclosure from moisture damage (see here).  Given these pretty convincing reasons, what should our airtightness target be, and how does a service cavity help us achieve it?

The challenge to reach recommended airsealing results – 3.0ACH50 in the new building codes or 0.6ACH50 to meet Passive House requirements – can be readily overcome with good strategies.  One key strategy, relatively new to the U.S. construction market but gaining ground, is to install a service cavity – or “installationsebene” in German.  A service cavity containing electrical and plumbing services greatly reduces the number of penetrations through the control layers.  So instead of hundreds of switches and lights puncturing the control layers and potentially compromising performance, the liability is minimized and greater robustness is assured.

The service cavity is formed by running 2×2 battens (or 2×3 on edge) horizontally inboard of the air and vapor control layer. This makes the electrician’s life easier, as they no longer have to drill through a large number of studs to wire the outlets and switches. The back of the service cavity can be made airtight with an intelligent vapor retarder (INTELLO Plus or DB+), or structural sheathing (preferably plywood) – in both cases taped with TESCON Vana at all seams and edges.

The service cavity can also be employed in a gut renovation of a Brownstone, or other buildings with structural brick walls. We offer plenty of service cavity details mixed in with our free CAD details and High Performance Historic Masonry Retrofits downloadable ebook. The airtightness of brick and mortar when the blowerdoor is creating a pressure difference of 50Pa is surprisingly low. To construct an airtight layer, first offset a 2×4 at sufficient depth from the brickwork for insulation purposes, then INTELLO Plus along with a service zone to the inside of this assembly. In this way a verifiable airtight layer can be constructed quickly, especially in comparison to coating the brick wall with a liquid applied membrane.

The larger stud walls behind the membrane should be filled with blown-in fiberous insulation after installation of the INTELLO Plus, or batt fibrous insulation can be installed beforehand. The blown-in holes can be quickly and easily repaired with Tescon Vana 150 (as shown below). The building is now ready to be blowerdoor tested, which should be early enough in the construction phase to correct any mistakes and get the building as tight as a Passive House / Enerphit project.

INTELLO service cavity after cellulose blow-in (clioma.ie)

After all services are installed and before installing the drywall, optional fibrous insulation or rock wool can then also be installed in that cavity.

Of course you would want to make sure that during this period no new holes are made in the airtight membrane. Instruct plumbers, electricians, and other trades that might carry a utility knife to not act like Zorro! After the insulation and drywall is installed, the airtight layer behind the service cavity will be protected from nails to hang pictures, screws to hang shelves , etc. Even wires for phones, cable, and internet can be easily installed without compromising the airtightness of the building for years to come.

We hope you all had a productive, safe, and successful July – we continue to thank you for your support, insight, and enthusiasm for the future of high performance, low carbon construction.

The Question of the Week for the last week of July comes from a building inspector in Colorado who was curious about the best retrofit solution for a wall assembly where it’s difficult to remove and re-install siding without damaging it in that process.

The question:

“To Whom it may concern,

I am interested in knowing the recommended assemblies for the Intello Product.

We have a lot of rehab work being done in our town on very old historical buildings. The contractors want to remove the exterior siding to install sheathing and house wrap; however, the siding is difficult to remove and re-install without it falling apart etc.

The idea is to use the Intello product on the inside face of the wall framing and potentially on the inside face of existing rafters. The walls have three layers of 1 x material on the outside and 2 x 4 wall framing. The roof metal will most likely be pulled off, new sheathing applied and Ice and Watershield applied. Will the Intello product work for these situations. Can it be used with closed cell spray foam.

Thanks in advance for your help.”

Our response:

“Dear A.,

This free details guide is the third in the 475 ebook series

2x wood frame construction is very common and typically provides poor performance. This free ebook illustrates how we can transform the 2x approach into a high-performance enclosure that affordably delivers the highest levels of comfort, energy efficiency and longevity.

Airtightness disproportionately effects enclosure thermal performance. A well insulated enclosure that is airtight can have one-fifth the energy loss compared to the an equally insulated but leaky enclosure. Airtightness is essential to optimizing the insulation performance. Today, building codes are adopting mandatory levels of airtightness, typically 3.0 ACH50. But with attention to details, materials, and sequencing, airtightness can – with just a little more effort – be achieved at 1.0 ACH50 or lower. With practice, Passive House performance of 0.6 ACH50 is readily achievable. Providing greater airtightness provides greater comfort, resilience and cost savings, essentially for free.

Just as Moore’s Law for computer processors has proven true – efficiency increases for progressively less money – today’s enclosures can add value in the form of comfort, energy efficiency, and resilience, for less cost through airtightness.