California Fire-Proof Concrete Roofs

NPR this morning belatedly did a story about how concrete buildings are more fire-resistant and might have prevented fire losses of homes in the California wildfires from the seasonal Santa Ana winds.

Readers of this site (IHB) know that I have advocated concrete for some time. See:

"Concrete, Wood, Steel, in New Construction"

Concrete has high compressive strength (downward pressure on walls) but low tensile strength (stretching), which is why builders often reinforce concrete with steel rebar to prevent sideways earth pressure from cracking basement walls.

Concrete's low tensile strength means short horizontal spans (the concrete's own weight pushes down and in effect tries to stretch its underside longer and crack it), which is why the Romans used arches or pillars with short lintel spans and narrow spaces between posts.

Modern concrete roofs can use steel reinforcement for high-tensile span strength and/or use lightweight concrete (concrete mixed with expanded Perlite to lower the density and hence the weight).

Soddies, Sod Houses, Pithouses, Dugout Houses, Sunken Buildings, Earth Houses, Earthsheltered Homes

Simple Science and Ancient Wisdom from the Vikings to Dick Cheney

Lynne Cheney (wife of Vice President Dick Cheney) mentioned in recent interviews about growing up in Wyoming that a relative lived in a "soddy"/"soddie" (sod house made of sod "Nebraska bricks") and her grandparents lived in a dugout house (dig into a hillside and cover the opening with Nebraska bricks or a wooden frame). A pithouse (sunken building) is a kind of dugout house but usually refers to digging down into flat ground and building a roof over the pit, often with branches and sod.

Soddies, dugouts, and pithouses are prairie versions of igloos or adobe.

You can find Native American pithouses, Viking pithouses, Saxon pithouses, and Japanese farmer pithouses at Numa.

All these earth houses use the same natural climate-control principle of a root cellar/fruit cellar.

The fancy modern terms of "earthsheltered," "living roofs," "green roofs," and "geothermal heating" are just (sometimes pretentious--and pricey) re-labeling of old, inexpensive wisdom.

Proud Homeowner: "My first house in Neb. 1880 built from 'Neb. brick'" (Photography by Solomon Devore Butcher, c. 1886, glass plate negative 6x8)

Dugout House with Wood-Framed Opening, Robbins Dugout, West Union T.P., Custer County Nebraska (Butcher, 1886)

Photo Gallery of Dugout Houses