CLT House by Susan Jones Shows the Future of Sustainable, Green and Healthy Housing

CLT house
credit: Lloyd Alter

It is the usual practice in covering architecture to wait until a building is complete before it gets published. However in the case of the CLT house in Seattle, designed by Susan Jones of atelierjones, I can't wait. That's because it's so TreeHugger; the house is relatively small at 1500 square feet, it's on an impossible triangular lot that really limits the design options, it's almost passive house, it's covered in one of my favorite materials, Shou sugi ban, but most importantly it is built of Cross-laminated timber (CLT), one of the most important innovations in wood construction of the last few decades. It is also going to be stunningly beautiful.

credit: AtelierJones

Cross-laminated timber or CLT shows up a lot on TreeHugger; that's because it's made from wood, a renewable resource, it sequesters carbon, it is strong enough to replace wood and concrete in higher buildings, and right now, it helps use up some of the billions of board-feet of mountain pine-beetle infested wood that will rot if we don't cut it and use it fast. CLT also makes a high quality house that is almost totally silent, is fire and earthquake resistant and is beautiful to look at. In Europe, it's used a lot in houses; after the 2009 earthquake in northern Italy they built 4,000 CLT houses to replace the block and stone houses that were destroyed. Susan Jones' CLT house is the first in Seattle and one of very few in North America but it won't be the last.

credit: AtelierJones

CLT is made in by pressing smaller dimension lumber into giant 8' by 50' panels, and most houses made out of it are also rectangular, but that would be too easy for Susan Jones' first attempt at using the stuff; She went and bought a ridiculous small triangular lot instead. This complicates everything from the design to the assembly of the house. It is a very clever plan for dealing with a triangular site; note the notch in the long side. This allows a lot more natural light into the house, but also defines and separates the living room and dining room spaces.

credit: Lloyd Alter

And where most architects would probably just plop a flat piece of CLT on the roof, Susan designed this complicated meeting of panels, all carefully mitred in Structurlam's Penticton BC factory. They all fit together perfectly when assembled on site. Engineer Harroitt Valentine designed a tension ring to hold it together and I suspect contractor Cascade Built had fun assembling it. This wasn't easy or as fast as it might be; with almost no open property, the builder sort of had to shuffle the deck of CLT panels each time he wanted to find one.

credit: Lloyd Alter/ Susan Jones and wall

In fact I wonder what they thought in Penticton when Susan walked in and said something like "lets take your router and cut out this pattern of holes and slots to make this feature in the master bedroom wall."

credit: AtelierJones

The effect, however, is beautiful and worth the trouble.

credit: Lloyd Alter

The shape of the roofs, the careful placement of skylights and the warm, natural wood combine to make dramatic and beautiful experiences of light and texture.

credit: Lloyd Alter

Most of the CLT in the house is seen side-on but in a few spots you can see the ends. Here you can see how they have used beetle-damaged wood in the cores of the panels, with its distinctive blue color that some have tried to turn into a virtue and market as denim pine. That never caught on, but I still hope that they offer a version made entirely from the damaged wood. I am sure it would be attractive and we have so much to go through.

credit: Lloyd Alter

I am loath to show any of my photos of the interior spaces; these should wait until the stuff is out and the professional photographer makes it look best. I will leave it with this one of the master bedroom, which gives you a sense of the warmth of the wood and the quality of the light. It is a work in progress and deserves better than my iPhone photos. There will be a sealer put on the walls; that's it, what you see is what you get with CLT.

credit: Lloyd Alter

Note how the windows are so beautifully and seamlessly detailed into the wall.

credit: Lloyd Alter

There is an interesting story happening outside the CLT too. This house is built like a Passive House, wrapped in an orange Wrapshield vapor permeable air barrier. Then there is a thick insulating blanket of Roxul rock wool, making this an almost foam-free house with much lower embodied energy. Because the rock wool compresses, the strapping is installed with crazy expensive Heco Topix screws that have a thread that reverses so that they only can go in a specific distance. The cladding is my second favorite material, Shou sugi ban, which is all the rage these days among Seattle architects. Susan doesn't know if it will meet passive house standards because of the air tightness requirements. The electrical wiring is done on the outside of the wood, so it has been drilled full of holes. A blower test will be done to test how close it gets to Passive House air change requirements. But there is so much else going on it's not a huge deal and really, Susan had enough on her plate here. It's a lot more work to do a wall this way rather than just covering it with blue foam and nailing through it. It also takes up more space. But a lot of architects are trying to get away from using foam.

credit: Lloyd Alter

Here is architect and future occupant Susan Jones in front of a completed section of the Shou sugi ban wall, dramatically describing its features.

credit: Lloyd Alter

There are so many things about this house that make it so important and so wonderful. It's very Japanese in the way it fills a tiny site (the overhanging prow is to leave room for a parking spot). It is built of one of the best carbon sinks we have, wood, in a strong new long-lasting form. It is built to almost passive house standards out of healthy and renewable materials. it is modest in size and efficient in layout, which is really hard on a triangular site. It is lovely to look at and is going to get lovelier every day. I believe this is going to be one of the most talked about houses of 2016 and it should be; it's inspiring, as is architect Susan Jones.