Post Tension Slab

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There seems to be many homes in Texas that use post tension slabs due to soil

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Because they have sandy soil that shifts a lot and it is almost impossible to find a good clay bed to build a pad. Some parts of Louisiana are the same but for the most part you can usually find a clay bed if you dig deep enough. I know the COE makes contractors use post tension slabs on Ft Polk because of sandy soil around there.

I have had to dig very deep before in South LA just to get past the old gumbo mud we have here. That can be as bad as sandy soil for a slab. It never seems to harden up. Might be your friends issue.

I have also seen some PT slabs that the builder didn't know what he was doing and it ruined the building. There was one at Ft Polk that the guy got sued over by the COE and it bankrupted him. Rumor is one of the cables broke and snapped out of the concrete. That much pressure with a steel cable could have cut someone in half.

I'd go traditional.

Most important is ensuring proper compaction of the subgrade and avoiding expansive soils.

I have the same question/problem here in NOLA. Not sure whether to go PT or rebar. Seems like they are about the same price too

Not definitive, but Google Web soil survey

USDA national resource conservation service website

Stout, you normally sound fairly educated about such matters, but to say clay is needed for a good subgrade is laughable. Clay is an extremely expansive material and tears slabs apart in Texas. This is precisely why post tension is used. Clay is hauled out and replaced with a low PI material such as sand or crusher fines.

To answer the OP, many engineers I trust will tell you post tension is bullshite. Beef up the thickness of the slab and grade beams and put plenty of rebar.

Just go with PT. It does cost a little more but a far superior system. It's not a cure all system but it will minimize problems you may have in the future.

Remember any slab is only as good as the soils supporting it. I'd guess that the significant majority of slab failures are a result of the soil below and not the foundation itself.

There are different types of clay. The clay here in SWLA where I am talking about is rock hard and I have built a lot of houses on top of it over the past 13 years with no slab issues.

I am also saying to simply get past the gumbo mud we have here and you'll know when you have done that when you see clay.

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Just go with PT. It does cost a little more but a far superior system. It's not a cure all system but it will minimize problems you may have in the future. Remember any slab is only as good as the soils supporting it. I'd guess that the significant majority of slab failures are a result of the soil below and not the foundation itself.

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PT is far superior but any slab is as good as the subgrade

Get a good engineered PTS and don't look back. We built in 1996 and had one with cables 3.5 feet apart. That slab was so tight. If the builder cuts costs and corners it can be an issue. A well engineered and designed PTS is about as good as you can get.

shite on that.

Of course the opposite is true here. I enjoy watching them drive pylons in the ground (AKA whole trees) here for the Casinos they build in the marsh or on road construction. Can't do that in too many parts of Texas.