Residential Design

Vol 1, 2018

A business-to-business magazine focused on the collaborative process and talented work of residential architects and custom homebuilders.

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to the ground. It caught on fire. Going forward, we're going to pay extra careful attention to what is at the base of the buildings, close to the ground. We saw that patios and porches made a difference, especially patios that run further out be- yond the porch columns. AT: We found that with heavy timber, redwood did better than Douglas fir. Redwood is more fire resistant. DA: We early on did a PISE house up in wine country. That's David Easton's term for rammed-earth construction [builder/ consultant David Easton of Rammed Earth Works]. It was 18 inches of solid PISE. Today, our energy code would not let us do that; we would do it with a thermal break and use straw bales...At any rate, the wood frame caught on fire, but not the walls. AT: On the PISE house, we used a wood cribbing detail. It was so beautiful with light coming through, but it was not good for fire. How fireproof your exterior walls are is another piece of the puzzle. Any exposed wood can be a problem. So, we're looking at cement board for a project we're doing in Nevada, and we're looking at metal siding. The devil is in the details of the whole picture. You have to watch your eave vents, so we're looking at eave products with intumescent coatings, like Vul- can. You have to make the soffit of non-combustible materials. It seems from the evidence of the fire, those kinds of details can make a difference. We're already designing for State of California Chapter 7 for Wildland Urban Interface standards, but you have to go further than that. DA: A Class A roof makes a big difference, too. Our go-to for roofs is metal, and we've already seen that metal roofing can help a lot. There are lots of tools in the tool box. Along with insurance industry concerns about straw bale, there appears to be a misconception among the lay public and even firefighters that it's more vulnerable to fire than conventional building materials. Why is that? DA: Most people don't understand there are certain assem- blies of straw-bale plaster walls that even exceed code. There is one assembly with lime plaster and bales stacked on edge that can last 2 hours, according to ASTM testing, and another for clay plaster in bales laid flat than can last an hour. Most residential doesn't usually achieve an hour. Some people complain that when fire reaches the straw- bale walls, they smolder. But when the bales are densely packed, the flame-spread index and smoke-developed index is within the limits. If you've ever thrown a phone book into a fire, it takes a long time for the oxygen to get through the densely packed pages. It takes a long time to burn. AT: Also the plaster really does slow down the fire by keep- ing the oxygen out. We did a straw bale studio and the roof burned, but the finish on the walls remained intact. Another aspect that's interesting is that you don't have the structure collapse when there's a fire. The effort to rebuild in wine country will be huge, especial- ly for a region that already saw shortages of skilled labor. You've made straw-bale house plans available to people who've lost houses to the fire, to help speed up the recovery. What else is a priority for the firm? AT: Although people want to rebuild quickly, and counties are helping, we want to do it in as healthy and as low-carbon a way as possible. And we're part of a group working on that. We'd like to see more net-zero construction to replace what's gone. We'd like to see more accessory dwelling units on individual lots to help alleviate housing shortages and afford- ability issues. DA: Building smaller is another opportunity. We had a fellow who contacted us and would like to replace 2,400 square feet. But if we can get all that livability in 1,800, why not do that? Beyond the architecture and the building, you have to extend thought and care into the landscape. They can work together to give you a better chance for survival. When the fires come again—and they will come again, wouldn't it be great if more houses survived? AT: It's not that we didn't think about fire before—we did— but it's amplified the consideration. Not just in California, but everywhere through the West. And yet, we still have to make sure that we create something that's livable—we can't just build fortresses. Above: Arkin Tilt's plaster supplier noted that the pink hue on the walls is from the fire heat drawing out the natural iron oxides. The soot brushes off. Photo: Michel Couvreaux Photo: Ed Caldwell 11 VOL. 1, 2018 RESIDENTIALDESIGNMAGA ZINE.COM

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