Inexpensive Home Building

Cut through the jargon and nonsense of home building and house construction by starting from zero dollars and trying to figure best-value bang-for-your-buck when choosing construction methods or construction materials. My research might answer some of your questions and at other times perhaps you have the knowledge or experience to post the answers to my questions and thereby help others too. The goal is an affordable and sustainable home for all.


Friday, October 26, 2007

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).

9 Comments:

At 7:50 PM, Anonymous grandmother said...

what happens in earthquakes?

 
At 10:53 AM, Blogger J at IHB and HFF said...

Hello. Properly anchored steel-reinforced concrete is strong. Some issues in earthquakes might be inelasticity, cracking, and spalling. Perhaps wire mesh or something like an anchored tin ceiling would reduce spalling.

See
http://www.cement.org/homes/brief10.asp
http://nisee.berkeley.edu/lessons/concretemm.html

 
At 8:52 PM, Anonymous Anonymous said...

True, concrete would be fire proof, but the problem in California is the earthquakes. I would be surprised if a concrete roof would survive an earthquake. I grew up in California and have seen many earthquakes. During big ones, the wooden homes are fine. Concrete and brick construction is reduced to rubble, because it simply cannot sway and move with the shockwaves. I saw this time and time again after earthquakes.

 
At 4:02 PM, Blogger J at IHB and HFF said...

Hello. We need to distinguish mortared masonry (brick, "cinder block") from monolithic, poured, steel-reinforced concrete.

 
At 5:47 AM, Anonymous Mold Remediation said...

It was great to go through your post. The information here is very useful and informative.

 
At 3:50 AM, Blogger toffelnigar said...

Kansas City pier masters Companies is a unique company in our industry in that we are not only just a construction company, but also a Professional Engineering firm in the state of Missouri, through our divisions of pier masters and pier masters MUDJACKERS. pier masters offer diversified, engineered structural support services and products. This site offers valuable information to our clients and prospective customers alike.

 
At 5:25 AM, Anonymous peter kenneth said...

The information in the post is useful .. Thank you so much for sharing it with us....

 
At 3:51 AM, Blogger Shazia Sahari said...

Welcome To KC Master Companies Founded in 1985, we have over 25 years of experience specializing in concrete repair, foundation repair and restoration, and waterproofing systems with our world best master mudjackers.

 
At 1:56 AM, Blogger hume concreting said...

Great Job

http://humeconcreting.com.au

 

Post a Comment

<< Home