On the contrary, most houses built in Arizona today have wood frames, and
virtually all of them have wood roofs, because wood is the cheapest, most
versatile, and easily worked structural building material. However, the wood
is usually covered up so you don't see it: exterior walls are usually
covered with stucco rather than wood siding, and the roofs are covered with
tile or asphalt shingles rather than wood shingles, because exposed wood
cracks and curls in the arid climate and is a more expensive covering.
Also contrary to popular belief, Arizona had very fine forests--the world's
largest stand of Ponderosa ("yellow") pine, which grows up to 3 m in
diameter and 800 years old. But they have been rapaciously logged over the
last 120 years and only small areas of virgin old-growth remain. However,
due to decades of misguided management by the private landowners and the
U.S. Forest Service (overzealous fire suppression, too much commercial
grazing and logging) there are extensive second-growth forests of spindly
"dog-hair" pines ("thicker than the hairs on a dog"), which are not only
useless for lumber but a tremendous fire hazard as well. Most of our lumber
now comes from the Pacific Northwest or Canada.
Some houses in Arizona (like my own) are constructed of concrete blocks,
but, again contrary to popular belief, they do not insulate as well as wood
walls filled with fiberglass, and of course you can't have a concrete block
roof. The worst thing about masonry is that, as Joe notes, it has very high
heat capacity, so not only do you swelter all day in the summer, but at
night when the outside air finally cools off, the damn wall continues to
radiate heat on you, so you still swelter.
The Spanish/Mexicans and the aboriginal inhabitants before them built of
field stone, adobe (sun-dried mud bricks), or wattle-and-daub (mud plastered
on a wood frame) mainly because it required less labor. It was too much work
to haul trees from the mountains (although they had to for the long roof
timbers, or vigas), and they didn't have the tools to saw trees into lumber.
In recent years there has been a modest revival of adobe among the
architecturally avant-garde, who are also experimenting with houses built of
straw-bales covered with stucco. Both provide good insulation because the
walls are so thick, but they are labor-intensive and therefore not cheap
(despite the cheap materials), they require a lot of maintenance, and I sure
wouldn't want to be in one in an earthquake!
> -----Original Message-----
> From: Joseph B. Reid
> >
> Kilopascal wrote in USMA 9720:
>
> My brother lives in Mesa,
> Arizona, and the
> >three times I visited him there, I never saw a wooden home or building.
> >Everything was "cement" or some similar material. I don't think
> wood/lumber
> >could take the high heat.
>
> > The basic reason that people in hot climates use masonry construction
> rather than wood is that masonry has a much larger heat capacity
> than wood.
> The result is that inside a heavy masonry building the temperature tends
> to be the 24-hour average exterior temperature. The cave men were not
> stupid.
>
> On the other hand, in climates where winter heating is needed, as in
> Canada, insulation rather than heat capacity is the more
> important quality.
>
>
