LESLIE: Brian in Arizona, welcome to The Money Pit. What can we do for you?
BRIAN: I’ve got a question. Is it more cost effective, in the long run, to build a house out of concrete rather than wood and, you know, normal building materials?
TOM: Yes. If we’re talking about insulated concrete forms. Is that what you’re referring to?
BRIAN: Yeah, I’ve heard of a product. It’s foam blocks, interlocks.
TOM: Yes.
BRIAN: Kind of like those LEGOs we had when we were a kid and then you pour concrete down in the middle of it.
TOM: Yep, exactly. They’re called ICFS – insulated concrete forms. And you’re exactly right in your description. You stack them up much like oversize LEGO blocks. Inside of the foam blocks you attach rebar – reinforcing rod – and then …
BRIAN: That was – OK, that was going to be my next question.
TOM: Right. Yeah, it gets – it depends on the block design but usually the webbing is designed so that you can sort of snap the rebar in place. And these foam walls are braced, obviously, on both sides so that they don’t collapse under the weight of the wet concrete. And the concrete is poured from the top. It’s a little more liquid than it might be for, say, a driveway or a slab. It settles in there. And then once it dries you have solid concrete exterior walls that are also super-insulated.
And there’s a lot of advantages to this that you’d never get with a wood-frame wall. For example, when you build an ICF house you can downsize your heating system by one-third. So, if your wood-framed house needed a 100,000-BTU furnace your insulated concrete form house would need like a 70,000-BTU furnace. So, you get a more energy-efficient house. You also get a very storm-resistant house. You don’t have to worry about flying debris from tornadoes and hurricanes and things like this. You get a quieter house. So for all of those reasons, I think ICF is an excellent technology.
LESLIE: How does it compare cost wise?
TOM: It’s about – well, it used to be about five percent more but now that’s actually come down because it’s become more popular. So it costs about the same amount of money to build an ICF house as it does a stick-built, wood-frame house. So I think it’s a really good idea.
There is a website called ConcreteHomes.org that is put together by the Portland Cement Association, which is an independent trade group of the concrete industry. And they did a really good job on that site of sort of collecting the information about concrete home technology. I’ve actually been following it for many years, Brian, and I really am impressed with the technology.
BRIAN: Excellent. Alright, excellent. So thank you guys so much.
TOM: You’re welcome, Brian. Thanks so much for calling us at 888-MONEY-PIT.
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