The Army, Navy, Air Force, General Services Administration and the Department of Energy and other private sector contractors will be participating.

The workshop is geared toward architects, engineers, project managers and contractors and will address topics relevant to new construction and deep energy retrofits.

As part of the event Berthold Kaufmann of PHI, and Tomas O’leary of the Passive House Academy (PHA) will make a series of presentations on Passive House construction.  Floris Keverling Buisman of 475 will be there too.   Be sure to meetup with Floris with an email to floris@foursevenfive.com.

To register for the workshop, contact:

•  2 ducts for HRV (supply and exhaust)
•  1 electric conduit which carries 3 cables
•  1 potable water supply pipe
•  1 sewer connection
•  1 cable/telephone wire

Kaflex gaskets are great, but always try to minimize the number of cables first (image: http://blog.proclima.com)

Although these leaks mostly do not appear on that red-line section you made, you should plan your connections to these ‘holes’ so they will be sealed properly and will remain airtight for the live of the building – which is the topic of this post – Of course, reducing the holes you have to a minimum is the first step, as it lessen the number of seals you need to make and worry about for getting to Passive House 0.6ACH50. Hence the use of service cavities to prevent unnecessary penetrations of your red line.

Only one cable per hole please

Recommendation number 1:

Only one pipe, cable, wire or duct per hole.

The reasoning behind this is that foam won’t expand it in the way you want it too, so it will not give you an airtight seal between the small spaces in-between the cables/pipes. This is explained quite well by Roger Lin at the bottom of this blog post of the Arlington Passive House. Furthermore shrinkage of the foam or movement of the cables will compromise foam-cable connection and thus compromise the seal. KAFLEX and ROFLEX EPDM gaskets are the preferred way to seal cables. (Note: sealing Romex will be subject of a future blog post)

Foaming many pipes and cables in one hole - looks airtight, but will still leak air (http://arlingtonpassivehouse.wordpress.com)

Recommendation number 2: Give your self space to make a good airseal.

Good amount of space to fit HRV ducts, apply insulation around them and plachttp://passivhausrefurb.blogspot.com/)e + tape ROFLEX gaskets (

You need at least a few inches around a larger duct to place your hand and press the tape securely to the membrane (see photo on the right). For smaller pipes and cables, you can work with smaller tolerances, but don’t make the job harder than it should be – it is just not worth it. The picture below shows a situation in which the conduit is already installed and a gasket can be slid over it. It will be practically impossible to get a 100% seal because of the different levels of wood surrounding it.

Recommendation 3:

Distribute gaskets early to plumbers/electrician so they get used

conduit to close to stud to make a proper sealed air-tight connection (vermontpassive.com)

Using TESCON No.1 in short strips to connect pipe to airtight layer

If you install gaskets over pipes and cables during installation, they remain adjustable and the connection/taping to the airtight layer can happen at a later date.Making the process quick, airtight and easy for all involved.

Yes, of course you can tape around pipes with a large amount of short strips of TESCON No.1 as shown on the right. This takes more time, is more prone to mistakes that cause small airleaks and won’t allow you to adjust the pipe anymore. However, it the pipes/cables are already installed this would be your only option, just be diligent and make the best seal you can.

Recommendation 4: No new holes!

This pipe and hangers were installed very late in a PH project and thus all of them needed to be taped with Tescon No.1, with some planning this could have been prevented

There is a chance that you will show up on site and find some new holes in the airtight layer – new plumbing pipes, extra exterior lights, cat-doors, sewer vents, etc. Either were installed late or weren’t on the plans but that the owner really wanted them and told the contractor to install. Recommended is to explain the importance and comfort that air-tightness will bring the owners (and contractor), have them witness a blowerdoor-test early on, which will hopefully mitigate these unannounced arrival of these new holes

(during construction and during the life of the building – a dedicate service entrance could be a remedy for utility and cable companies to counter their leaking service installations – however, you still need to watch them….).

McGraw Hill Construction

McGraw Hill has just released key findings of a new study/survey to be published in April, showing that while residential construction has collapsed over the last several years, green construction has been steadily growing – gaining significant market share in the process, and totaling approximately 17%, or $17 billion in 2011.  McGraw Hill estimates that as residential construction rebounds, the green market growth with accelerate, exceeding a 30% share or $100 billion by 2016 – a five fold increase in five years.

For evidence of this green explosion one needed only to attend last week’s Better Buildings by Design Conference in Burlington Vermont.   Produced by Efficiency Vermont, this “little” conference packed a punch – with informative and wide ranging talks on building science and efficiency, from luminaries such as John Straube of Building Science Corp and Bill Maclay of Maclay Architects, as well technical talks on ventilation by Barry Stephens of Zehnder America and data collection by Peter Schneider of Efficiency Vermont - to name just a very few.

Better Buildings by Design

And the exhibitor floor was packed with important players in the green building world from National Fiber to Preferred Building Systems.   But perhaps the most important aspect of the conference were the attendees – a cross section of professionals committed to building more efficient, comfortable and healthy buildings.  Contractors, architects, college professors, developers and specialists, made for two days of interesting and intense conversation that was impressive and inspiring.   475 was very happy to be there as an exhibitor and to meet so many dedicated people.  We look forward to being back in 2013, and encourage you to be there too.

To many, many more better (green) buildings.

Control Layer Priorities:

1. a rain control layer
2. an air control layer
3. a vapor control layer
4. a thermal control layer

In this post we’ll discuss the importance of air tightness.

Air control at the enclosure is so important (two notches above insulation) because it has profound effects on:

1. Indoor Air Quality (IAQ)
2. The optimization of thermal insulation
3. Prevention of bulk vapor penetration.

Indoor Air Quality (IAQ)

You can’t control the quality of the air we breathe until we control it physically.   Unfortunately this is a widely ignored fundamental truth.   Until we control the air flow through a home the IAQ is a crapshoot.    And the first step in controlling the air flow in a building is an airtight enclosure with a continuous air barrier.

Ventilation fresh air filter, full of exterior soot, pollen and other contaminants

Once an airtight enclosure is established, the air inside can be controlled predictably and efficiently.   High IAQ becomes not only possible but simple to achieve.   Fresh air can be brought in continuously with stale air exhausted continuously.    The fresh air is filtered as it enters the home, removing soot, pollen and other pollutants and supplied to living areas.   Exhaust air is taken from bathrooms and kitchens and brought through a high efficiency heat exchanger, swapping its energy to the incoming fresh air before it is expelled to the outside.

In this way – made possible with an airtight enclosure – air quality inside the home may be superior to the outdoor air quality.

Optimization of Insulation

Air leaks through the enclosure can severely compromise the effectiveness of the thermal control layer.  A study by the Fraunhofer Institute for Building Physics, in Stuttgart, showed that a leaky enclosure can decrease the insulation’s effectiveness by a factor of 4.8 – making a 500 sf leaky building require the same amount of heating as a 2,400 sf airtight building!

Diagram of insulation unprotected by air tightness (at left) and protected by air tightness (at right).

Consider your sweater on a breezy day, and the effect of putting on a windbreaker.

The insulation performance is best optimized with an air-tight layer on all sides: an air-tight layer at its interior face (such as Intello Plus) and a wind-tight/air-tight layer on the exterior face (such as Solitex Mento).

If you are going to bother to insulate, get the most out of it with with complete air sealing and airtightness.

Prevention of Bulk Vapor Penetration

BSC: diffusion wetting vs. air leak wetting.

While there is much gnashing of the teeth (and some of it rightly so) about vapor diffusion resulting in condensation and structural damage, a far bigger threat to the structure is bulk water vapor penetration via air leaks in well insulated buildings.

With this iconic diagram from the Building Science Corporation paper RR-0412: Insulations, Sheathings and Vapor Retarders, one can see that the potential water intrusion from just a small air leak can be up to 90 times greater than the water that might diffuse through gypsum board into the enclosure.

With such extreme wetting, even a vapor open construction may not be able to dry fast enough to keep the structure safe.   Here we see water damage from an air leak in a such a vapor open construction.

Water damage from air leaks in vapor open construction.

Uncontrolled air movement through OR within* the building enclosure, carrying bulk vapor, causes the greatest amount of moisture related building damage.  Keeping the enclosure airtight on the interior is an essential step in keeping it dry.

*convective loops within wall cavities can transport and deposit bulk vapor when it reaches the dew point.

Conclusion

Because air tightness is essential for clean indoor air, optimized insulation and minimizing of wetting damage, it should be seen as a fundamental and integrated insurance policy on the performance of the building.   The more airtight your enclosure, the better the insurance policy you have.

Using SOLITEX membrane to pre install airbarrier around rim joist of 2nd floor passivehouse1nz

If you can avoid it, keep beams and joists from going through your continuous “red pencil line” airtight layer. Simple means to do this is running your airtight layer over your ground floor (tape the plywood), and under your roof (taped vapor variable INTELLO membrane under the beams). However, if you have a floor within your thermal and airtight envelope, you would still need to deal with the joist that carry this floor.

Wrapping a strip of SOLITEX around the joist for an airtight layer

In new construction you can and should design the airtight layer around these issues. You can wrap SOLITEX membrane strips around the joist as shown above and to the right. Of course you need to plan this well, as the membrane has to be installed before the joist are set, and need to be wrapped around these joists (optionally around the rim-joist too) and over the floor before the 2nd story wall is build. It can be durably connected with TESCON Vana tape when the interior airbarrier (Plywood, OSB, INTELLO) is installed.

Another way to deal with this, is the method as described by Gregory La Vardera on his Lami Design blog. It simply continues the airtight layer straight on the inside of the service cavity and uses a ledger board to carry the joist – no more difficult wrapping of membranes around joists needed. just straight runs – reducing complications and chances of errors which should result in an even tighter house and will allow you to get below 0.6ach50 without to many sleepless nights.

Airtight membrane and ledger board solution to keep things simple (more images at lamidesign.com)

The added benefit to last approach is the the heatflow parallel with the grain of the wood (as is the case with joist) is about 3 times as conductive – 0.38 W/mk, R-0.37/in) compared to 0.13W/mk, R-1.1/in for across the grain – thus keeping the joist ends as far away from your insulation layer has multiple benefits. Both putting the rim joist behind (some insulation as in the 3d image) as well as in Greg’s solution thus prevents a good amount of ‘cold/thermal bridging’.

Deutsche Bank & Living Cities

The report, produced by HR&A Advisors and Steven Winter Associates, with assists by Michael Blasnik & Associates and the Northern Manhattan Improvement Corporation,  analyzed pre- and post- energy use of 231 retrofit projects, totaling over 21,000 units of affordable housing, that had completed the NYSERDA Assisted Multifamily Program.

The average gains measured for building owners were modest,  with heating fuel reduction of 19% and electric reduction of 7%, yet financially significant and compelling.

Other key findings include:

• Fuel measures save [much, much] more than electric measures.
• The worse the performance of the building, the bigger the potential savings upside.
• Handicapping performance goals based on overall market data enhances the likelihood of any individual building hitting projected performance.
• Risk factors are understood and there are effective and clear measures to mitigate them.

I encourage you to chew through this wonderful report here (pdf).

BUT I think this report is more important than showing a clear methodology toward financing energy efficiency retrofits and it is this:

The report infers that a building’s energy consumption is a fundamental financial liabilty in the ownership of the building.   Like property taxes and operations staffing, energy consumption is a big number on the balance sheet.  Yet unlike property taxes and operations, the financial liability of energy consumption is within the power of the building owner to  significantly reduce.  (If they can just get the financing.)

I can’t help but imagine what the possibilities could be if deep-energy and Passive House level retrofits were made part of the equation.   With 90% reduction in heating demand, the building owner and financial lender would be crazy, IMHO, not to consider the huge financial upside of a Passive House retrofit.   One step at a time, I guess….

Buy the movie here, and enjoy these previews featuring Sam and Floris

Floris explaining blowerdoor testing for passive houses:

Sam talking about airtight windows:

Front of 130th street with triple pane windows

Passive House construction methods and PHPP to calculate it’s loads is on West 130th street in Harlem.

Gennaro and his crew from Ecobrooklyn, as per their company philosophy used reclaimed materials or rapidly renewable material were they could, but to make the building truly sustainable used energy saving/durable materials where required. This included Rieder triple-pane windows from Austria, a A.O Smith 80 gallon heat-pump water heater and to airseal this Brownstone a selection of tapes and membranes by Pro Clima

One of the hardest parts of making a NYC Brownstone a Passive House is not the level of insulation required, most of the time an R-21 or so wall will get the job done, but the airsealing of the front/back and party walls.

CONTEGA FC fleece tape taped to joist

Gennaro knew this well, especially that the corners of the building and the connections of the floor joist to the brick walls are sources of major airleaks and thus have to be dealt with. As sprayfoam and other sealants were out of the question, for both environmental (off gassing) and durability reasons (will crack and leak over time). The solution was to connect the party walls that would be covered/airsealed with a clay plaster to the joist with a felt tape. This 3-3/8″ wide tape, called CONTEGA FC  is adhered all the way around the joist before the clay application. The untaped fleece side is then embedded in the plaster, which assures a long term, durable and airtight connection between the plastered brick wall, and the airtight joist. This will allow the airtight layer to remain intact even if unlike materials moves/expand/contract slightly.

Plastered in CONTEGA FC, brick was coated with 2 layers of clay later to make it airtight

The first blowerdoor test, resulted in 3.0ACH50. A large amount of small leaks were found (basement, plumbing penetrations, etc.). The joist connections were performing well, however it was noted that the clay plaster leaked at certain spots and was to thin to perform as the proper airtight layer. After an additional layer of clay was applied, a couple more blowerdoors and the remaining holes were sealed – Gennaro reported an impressive blowerdoor flow rate of 300 CFM – which converts to 0.75ACH50 for this Brownstone – as far as we know the tightest house in Manhattan.

Congratulations to Ecobrooklyn crew with this fantastic result, the important work of sealing all the joist paid off!

INTELLO Plus under roof joist with service cavity - dense pack cellulose above

Products used:

INTELLO Plus under the roof joists, taped together UNITAPE and connected to plaster wall with CONTEGA FC.

TESCON Profil and UNITAPE at and around window boxes.

photo: Uli Seit for the NY Times

Been meaning to get this great article posted, here. While the title of “Zero Energy” is a tad misleading – the article, by Alison Gregor, does an admirable job summarizing Passive House and all the activity happening in the New York City region.

Of course I’m proud to be mentioned, and particularly like the article’s ending:

“So the Passivhaus standards,” Mr. Levenson said, “where you’re talking up to 90 percent reduction in heating and cooling, really changes the whole paradigm.”

May the new year bring lots of paradigm changes.

The Passive House Academy in Dublin is going to run us through a week long training course consisting of theory, hands on air sealing, technology installs, tours of past & current PH projects and a window manufacturing plant. And for those in the group who feel up to it, PHI will be holding its inaugural tradesman certification test on 1/28. Is there a better way to start the new year!

http://passivehouse-trades.org