Phoenix Passive House Completed!

Images: Eckert & Eckert Photography

The Phoenix Passive House project has made it to market!   

A big thanks to all those who worked on the project and helped to get us to this day!  Especially the amazing Passive House community here in the Pacific Northwest.  We really appreciate the open atmosphere of from some of the best builders, engineers and architects in the country that always made themselves open to looking at detailed drawings and answering questions along the way.   Without the openness that this community shows to High performance building, I don't think we could have gotten such a grand project completed!

We will showcase some details of the project on other blog posts, but wanted to get Pete Eckert's amazing photos online right away!  Thanks Pete!

We have been working hard to get as much press as we could for this very special project.   Look for this Phoenix to be involved in Dwell, Realtor.com's newsletter, PHNW, and other great publications.   If anyone is interested in knowing more about High-performance Building or Passive House in general, please contact us.  We love to spread the word!

Thanks again for your interest!

 

Materials Matter

I have to say, sometimes I feel like I am living a Portlandia episode when I talk about the materials in our projects.   The Phoenix PH is no exception!

The horizontal lap siding we chose is style number WC-115, the same siding that you will see covering much of the older neighborhoods in Portland, especially on larger homes.   It's popularity lasted a while in the city, but was replaced with wider siding for ease of installation and lower costs I assume.   We installed it without corner boards to help it have a more contemporary look that makes the north side of the home feel more like a uniform object that contrasts with it's rough-sawn cedar half.

That cedar half by the way, is all FSC certified, Oregon grown cedar.  It was milled by Kasters Kustom Cutting in Mulino, OR and molded by Trillium Pacific in Hubbard.    Everyone was worried about the 20' long 1x2's but we had no problems with them at all.  The wood is solid, and will naturally change color over time to a lovely silvery-grey.  

You have 2 choices with wood; you can fight it or you can accept it.  We think that whenever possible you should accept the beauty of wood for what it is. Some of the siding on the Phoenix is stained white (stains allow the wood to breath, where paints get in the way) because we loved the contrast of white on wood and it lets us really focus on the special qualities of the wood we left bare as well as the special architectural moves we planned.

 

 

Rockin' on the Inside...

It always feels great when the drywall goes in and you finally get a sense for how the spaces will feel.   Often people think that the drywall going in means the project is about over, in reality it is about at the half way point.   There are so many details that go into the completion of a good project that it just takes as long to get the finishing completed properly as it does the framing.   Still, it is nice to see the project moving along, and great to feel just how the spaces are measuring up!

If you look closely you can see that the drywall doesn't touch the floor in this home.   Instead, we decided to set the base flush with the face of the drywall for an extra clean & contemporary look.

You can also see how our by pushing the windows to the edge of the walls provides extra daylight deep into the spaces by using the wall as a reflector for the sun.  Very Nice!

 

It's not 8,000 lbs of Insulation...It's 8,000 lbs of "Thermal Battery"!

The first thing everyone asks us when we mention our passive house business is "how much insulation do you need?"  Well...a lot!

Insulation not only keeps the energy in the house on cool days, it also keep the energy out of the house on hot ones (solar gain is not just for windows — the sun shines on your walls and roof too).  Insulation works not just by stoping heat (energy) from moving through an assembly but by absorbing the energy and thereby slowing its movement to the other side.   

This energy is then released slowly helping to temper spaces in the building and stop big swings in temperature between day and night.  This ability to store energy when it is hot and release it when it gets cool basically turns your building into a "Thermal Battery".  Just like a battery, you store energy (heat) and then release it later.

We spend a lot of time making sure that every cavity in the envelope is fully insulated.  Even one missed cavity can cause problematic condensation by allowing a section of the building to get colder than the rest.  This condensation could potentially lead to mold growth if it doesn't get dried out.   

Every cavity that is filled in our projects is checked for proper density, ensuring a well insulated and high performing building!

 

Air Sealing is not for Sissies!

Any high performance Builder will tell you that if there is any magic in building to super high standards it is in the Air Sealing!  The Passive House Institute sets a benchmark for buildings to approximately 0.6 ACH50 for minimum certification.  What does this mean?  It means that when measured with pressurized testing equipment, the building being tested needs to have almost no holes in the exterior walls, floor or roof.  These holes, even if they are small ones, let through energy & water making the interior space less comfortable, and less healthy.  Even super small cracks and openings let in dust that is itself super small.  These particulates build up over time since they can't get back out through the same holes they came in though (think about how you could get salt back into a shaker through the same holes it comes out of).   

There is quite a bit of literature on the many gallons (yes GALLONS) of water that can accumulate through even the smallest holes in an assembly.  This is the main way that assemblies can have issues with decay and mold or mildew growth, and eventually cause failures.  

ACH50 means Air Changes per Hour at 50 pascals. Just like you can blow up a balloon with air pressure, a building can be pressurized with a computerized fan. The computer can record the volume of air that is being moved through the fan, and this volume of air has to come from someplace, right?  So that volume is relative to the openings in the assembly.  The more openings, cracks, or holes in the assembly, the more air goes through the fan at a set amount of pressure.  The less air that goes through the fan, the fewer the openings....pretty simple really.

The 0.6 part of the requirement is the minimum that the old system would allow, but the issue was that if you had a large building the amount of allowed openings (no structure built in the real world can have no cracks, of any kind) is large and the smaller the building is the small the amount of openings allowed.  The obvious issue with this was that it then becomes easier to build bigger and harder to build small.  The exact opposite of building to an environmental ideal!

The solution to this is that the requirement needs to be linked to the square footage of the house in a more direct way.  So the new standard is a bit more complicated, but more fair too. <0.05 cubic feet per minute/sqft. of shell area @ 50 Pa

 

What the Heck is Agepan!?

Once we had the air barrier and the TJIs in place, we needed to have a weather barrier over the TJIs to protect the house and to hold in the cellulose insulation.  We spent a lot of time going back and forth over this and with some help from Albert at Small Planet Supply and some testing on our part, we decided that a material called Agepan was the best product for our weather resistant barrier (WRB).

Agepan is a wax-impregnated wood fiberboard material that has a perm rating of 18 (Must Keep Assembly Vapor-Open!).  It gives us a small bump in our R-value for the assembly, but it's real value is in its water management abilities.  Even though it looks a bit like simple particle board (which you never want to get wet) it functions in a very different way.  We did a test (not particularly scientific) whereby we turned a glass of water over on a sample of the material and waited to see how long it would take for the water to seep into the product and wet the other side.  After 3 weeks of watching the test in our office, it still didn't show any signs at all of the water leaching into the material, let alone to the other side.  Talking to other contractors who have used this product, they had similar experiences as to how well this material performs as a weather barrier.  

Agepan installs relatively easily due to its Tongue & Groove edges on all four sides.  This T&G lets it be installed without having to have its edges land on the center of each stud in order to be strong enough.  The T&G can hold itself together, basically.  This is good because this is a product made in Europe (one of the few we used) and the size of the sheets are odd for U.S. construction standards.   

I have to say that even with the T&G, the install was not quite as easy as we had hoped it would be.  Large walls were easy enough until we got to the gables, where we were having to make angled cuts.  Since the sheets are so short (25" tall x 90" wide) we had twice as many cuts as we would have with a typical 4x8 sheet good.  Also, once we got to areas that were shorter in width, it turned in to a lot more cutting there too.  Once it is cut, there is no T&G there obviously, so that butt joint needs to be addressed with sealant and tape just like any other sheet good would have to be.

Slippery as Snot!
— Sparks Baughman, framer

Another negative for the product is that its waxy factory-delivered surface that is designed to shed water also sheds people quite well too!

The framers who installed the material on the roof for us found out quick that great care needs to be taken in where you put your feet on this stuff.  Our 5:12 & 6:12 pitched roofs created a tough situation for them, and the dust remaining on the board from cutting made the install treacherous & slow-going.

All in all, I like the material a lot and I am glad we used it over a membrane material, but the added cost of time, material & labor will make me consider a Siga Majvest, or other membrane material on future jobs.

 

Build Local Alliance Tour!...

A HUGE Thank You to the Build Local Alliance, Sustainable Northwest, Michelle Jeresek, Alden Boetsch, and everyone who came out to tour our Passive House this Saturday!

It was a scorcher, but everyone was in a great mood and we had some really excellent questions.  It is always fun for us to talk to people about Passive House, and to show off our work.

We look forward to the next walk-through!

 

How to hold 9.5" of Soft & Fluffy Insulation on the Outside of your House...

We are trying to build a 'no-foam' home, so we need to use the most environmentally friendly insulation we can find.  For us that is cellulose, a product made from simply shredding old newspapers (pretty darn eco-friendly we think!).

The issue is how do you you get enough cellulose into your wall assembly to get the high R-Values we need?   Since cellulose is so light and fluffy, you need to add something structural to the envelope to hold the it in, and to attach all your siding too as well. 

We chose a tried and true system of attaching vertical wooden I-Joists to the structure of the home on the outside of the plywood sheathing.  

This works GREAT!

This is also a giant pain in the butt!

First, you have to make sure you have built the house so that the 2nd and 1st story studs line up with each other, so the I-Joists can span from the very bottom of the house to the very top plate.

Second, you have to install them everywhere!  Basically we are re-framing our project.  A huge time consuming effort as well as a hit to the pocketbook, and a big increase in the embodied energy of the home.   We dodged the energy part by using local wood, and we were hoping to use FSC certified I-Joists.  Sadly we couldn't get the FSC product in time, so had to use 'normal' ones.  Still, adding wood product, grown in at least marginally managed, local forests is far better than framing the project even once in steel or concrete, so we feel OK about that.

Finally, it took about 3.5 weeks for us to install all the roof & wall I-joists.  Since we had never done this before, we estimated it would take about half that time.  This is likely the reason that some other companies have opted to try their hand at attaching insulation like Rockwool to the exterior instead.  Talking with them about this, that technique seems to have it's own difficulties as well!

In the end we have a really strong, bullet-proof system, but in the future we may also be looking at other ways to bump our R-value.

If this was a 'from-the-ground-up' project we would have gone with a double stud wall cavity.  But, even this has the issue of where to put the air barrier, so I guess there is no magic bullet yet, but we are working on it!

I have to say though...we got LOTS of people stopping by when we had the I-joists exposed on this project.  Builders from all over the country and the world have somehow just happened on our site and stopped to ask us what is going on!  One guy was biking by on a trip from Santa Cruz to Virginia!  Another was here visiting his daughter from DC.  Everyone wants to check out the details and all had really lovely comments on the quality of work we were doing.

Funny how so many people LOVE to see a well-built house, but how few of them are being built these days.  We are really happy to have the opportunity to do this level of work, and proud to be involved in the Passive House revolution!

 

 

The Roof...or should we say ROOFS?...

Most homes have one roof...pretty normal, right?

A few years back I was talking with a roofer about how heat is the big killer for most roofs.   I half-jokingly said that we should just build a shade over the roof to protect it.  Something like a second roof that takes all the sun damage and weather and preserves the 'real' roof.

Well, basically that is what we have done here.  We have your typical 1/2" plywood roof that we have air sealed. Then we added another structural layer to this to hold more insulation.   On top of this we added a weather protection layer made out of wood fibers and wax called Agepan.  Above all this we added a vented cavity for drying and another 1/2" plywood layer!

So where I was joking about 2 roofs, we actual have 3 of them on this project! 1-structural, 2-Vented Thermal Barrier, 3-Weather-Proof Top Layer with a metal roof on this...Hmm we may officially have 4 I guess!

 

Thanks for Coming to Our First Tour!...

We had a fantastic turnout for our first Open House/Tour!

Thanks to all who showed! In all we had over 40 people tour the project and listen to a quick presentation on what we are trying to achieve, and how Passive House can help us build better buildings.

We will have another tour on June 27th as part of the Build Local Alliance's Summer Event!  We hope you can make that as well.

As always, educating tradespeople and homeowners is one of our main missions, and if you can't make these public tours, feel free to contact us for a private tour or to chat about high-performance building.

We LOVE this stuff!