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Block Foundation - Is this regional?

Posted by dlm2000 (My Page) on
Sun, Jun 10, 12 at 22:37

We live in suburban Chicago but have been house hunting and looking at some in process builds in western North Carolina. Almost everything we look at has a block foundation, something that is largely unheard of here. Certainly there are climate differences from Chicago to NC but beyond that, we're having trouble understanding why we don't see poured concrete foundations there. It doesn't seem that there would be a significant cost difference once you account for the labor required for the block, but maybe I'm missing something? Admittedly, our comfort is in what we're familiar with, poured foundations, but obviously lots of people live in lovely houses with block foundations and are perfectly comfortable.

Can someone do a simple run down of engineering differences, cost differences or other significant differences for me? I appreciate your input.


Follow-Up Postings:

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RE: Block Foundation - Is this regional?

Do you mean an actual basement, underground? Block walls are surprisingly weak unless they are surface bonded and filled with re-bar and concrete. A poured wall (properly done) is much stronger. I didn't think anyone was doing block below grade anymore.


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RE: Block Foundation - Is this regional?

The most common reasons to use CMU for a basement foundation are: 1) to save money, and 2) the site may be too far from a concrete plant.

In NC, assuming the CMU is properly reinforced, the major disadvantage is poor resistance to sub-surface water penetration. In most situations concrete only needs needs a spray-on cold modified (rubberized) asphalt waterproofing but a CMU wall should have a waterproofing membrane. Both should have a footing drain.

In an existing house you should look carefully for signs of water in the basement.


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RE: Block Foundation - Is this regional?

Very common to see block in the Northeast and along the coast in my experience.


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RE: Block Foundation - Is this regional?

flgargoyle we are only looking at homes with basements and are as surprised as you to see block foundations for just the reasons you mention. We've seen it on homes 50 years old and current builds and it does concern us.

palimpsest that does surprise me. I've been in old homes in NE with stone foundations but not block.... but then we haven't been house hunting there.

Renovator8 - I appreciate that input. Never even thought of distance from the source because EVERYTHING around here is right here! That's going to be a big adjustment. I'm still surprised there is a cost savings if a concrete plant is available. Doesn't the added labor of laying the block and (I assume) reinforcing it and using a waterproof membrane offset any savings of forms and concrete? My husband is a mechanical engineer by education and residential engineer doing *everything* by trade and he is flipping out about these foundations.

In a perfect world we'd build - he's always wanted to - but I have major concerns about trying to do that at all, let alone manage a build long distance. I read this forum regularly because I'm a house geek, love the process and going along for the ride with the highs and lows in the builds. But those lows - some of them abysmally low - concern me and the cost of new construction vs remodeling (because we do it all ourselves) is prohibitive. Not sure if we can find a house in the area we are looking if we specify no block :(


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RE: Block Foundation - Is this regional?

I've built homes with poured and block foundations and even mixtures of both.

The cost advantage of block, where there is an advantage, can have as much to do with the illegally inflated prices of poured foundations as any other factor. As well, all the forming companies may be required to hire union labour while a block foundation can be built by anyone. This especially applies to small infill or single homes where there's no great financial interest involved. In harder times in my area, visits from union representatives suggesting that the general contractor may want to reconsider his non-union decision were not uncommon. (And, no, I won't name names.)

Appropriate building techniques are needed with either type of foundation in regards to dampproofing/waterproofing, insulation and termite control.


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RE: Block Foundation - Is this regional?

Block foundations are everywhere here in PA!

And they can't be too weak... my house was built in 1966 and we have no issues with it. Not even water.


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RE: Block Foundation - Is this regional?

I live in Pa, and have not seen block foundation houses. We built our current house and it has a poured concrete foundation. We are also in the process of building our next house, which also has a poured concrete foundation.


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RE: Block Foundation - Is this regional?

LOL! You must be in a new development then.
Poured concrete did not exist when the houses around here were built.

Every one of the 240 houses in my neighborhood have concrete block.


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RE: Block Foundation - Is this regional?

I originally came from Minnesota, where most of the basements were block. I dont know anyone that had a problem with them. I suspect, like a lot of other things, that the way things are done is regional. Here very few have basements, but those that do, are all block. Most foundations with a crawl space are also block. My last house had the block foundation. This house has block also, but it is covered over with Bedford stone like the rest of the house.


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RE: Block Foundation - Is this regional?

I'm still unclear. Are we talking crawlspaces or basements. In my area of NC (triangle), basements are poured and crawls are blocks. I've not seen a deviation from that at all. Sure old houses have blocks in a basement but not new.

So you need to clarify, are you talking crawls which are the vast majority of homes or basements?

And where in NC? People seem to forget that we have a more diverse climate and topography then say places like Illinois. The mountains certainly have more block but there are a lot of walkout basements in older homes. The beach has a lot of block in older homes. The distance to concrete plants may have a role in those locales.

There are no union issues in NC, I promise.


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Ah Basement

I now see the basement comment....

I can tell you that in the triangle, I've not seen block. I was building 1999 in a Sunstar development that got bought by Lennar and they were using poured concrete. For those that don't know, Lennar is low end developer. And that was 13 years ago.

Perhaps you are looking at rural areas? Perhaps they don't take waterproofing very seriously or codes very seriously? But with the water table and clay soil around here, I can't imagine block in 2012


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RE: Block Foundation - Is this regional?

David raises a good point - you want to check the soil composition. There are clay soils that are stable and others that are expansive - the latter are BAD NEWS for any foundation. I am partial to poured concrete for a true basement as well, but I guess it all depends on the site prep and waterproofing steps.


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RE: Block Foundation - Is this regional?

Our house was built in 1922, we are in the piedmont in NC. Our foundation is poured concrete. We have a full basement in part of the house and crawl in the other half. Everything is poured concrete.


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