PO Box 2458, Tijeras NM 87059

Mountain Gardens--finding success with plants for the high desert and East Mountains of New Mexico

Wednesday, November 16, 2011

Fireproof Houses

Ok, ok--anything will burn if it gets hot enough. Concrete and rock will crumble or shatter, glass and metal will melt. But...as per my previous post, there are strategies that can  make you almost fireproof especially if you incorporate them from the beginning.
Rastra wall

 Masonry and concrete are the materials of choice (see Fire Safe Building Design, Structure Mag). There are new and affordable building materials like SmartBlock, precast, and rastra--beams made of recycled styrofoam and concrete. We've used rastra ourselves, and find it sustainable, durable and easy to work with. You can cut it with a hand saw, mortar it with foam, and coat it with earthen plaster. It's surprisingly light, and a relatively large beam can be lifted in place by hand. Once in place the channels can be poured with concrete or packed with clay.

Old materials like adobe and strawbale are surprisingly fire resistant when coated with three or more inches of mud.. Stucco is better than wood siding but under high heat it can shatter and allow fire access to interior framing. Double pane windows have a huge benefit, resisting shattering where single glazing would break and allow fire entry (keep flammable materials away from windows for this reason). There is heat reflective glass! Steel framed windows are the best, then wood and aluminum. Vinyl melts, so even if the glass is intact.... This Old House has a great list of fire resistant materials, too, including tile and metal roofing, paints and more.

In the design and building process, make sure simple things like fire blocks aren't overlooked. Use roof vents instead of soffit or eave vents which can give fire ready access to attic and roof spaces. Since embers can pile up dramatically, you should use masonry, concrete or stone on the first two feet of foundation, and columns for porches and decks should sit on two feet of concrete piling. Keep wall and roof designs simple--embers pile up in those picturesque angles, cubbies, and corners. Reconsider upper story wood decks or balconies for the same reason--blowing embers can pile high and ignite them rapidly. Especially dangerous are wood decks that face a downhill slope. Fire climbs slopes rapidly. If you have an existing deck consider walling it in underneath with cinderblock, or building a stone or masonry wall as a firebreak. If you use wood columns, heavy timbers resist fire much longer than framing wood.

Global warming projections call for increased wildfire in the southwest, and if we don't get significant relief from current drought conditions, here in the East Mountains that may be sooner than later. Combining these building strategies with a plan for defensible space (our previous blog) will go a long way toward making you safer in the event of wildfire.

There's a lot of material available online (beyond the scope of this blog although I promise to get my fire resistant plant list up soon). I urge everyone who eyes every dark smudge on the horizon with anxiety to do the research, and implement some of these changes.


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  2. “Masonry and concrete are the materials of choice.” – You’re definitely right about this. It is the decision of the homeowner of what he wants to incorporate with the construction of the house. And if you have any plan of fireproofing your house, it’s better to start it while the construction is ongoing. Some do it years after, when they’ve seen the need for it. It’s okay but, personally, I think it is even better if the fire-proof materials are blended within and not just a top coat. Jake Nicholson