Question about SA home construction - slab ? P & B ? (Houston: houses, price)

[steve807]

I've recently moved into a 12yr old Perry constructed suburb house (in the $300K range) on a bit of a hill.

The lower row of bricks looks to be sitting on a plain concrete slab, probably 8" thick. In the front of the house anyway it looks like a conventional slab, but as you go down hill to the back yard the plain concrete bottom wall gets much higher before the start of the bricks. It is several feet of concrete before the (level with the bottom of the front brickwork) bricks begin.

I expect the concrete I see out back may be a layer of smooth stucco over some concrete bricks but that is a guess. This is based on some dings and damage in that layer from who knows what.

Do you think this house has a continuous and flat concrete slab (with some variable thickness fill blocks to keep the bottom of the bricks level) or some kind of pier and beam construction ?

[TrapperL]

Assuming that there was no screw up at time of pour, the slab would have been poured as one piece all at one time. This does not include flatwork like driveways, sidewalks, etc. More than likely your slab is a post tension meaning it has very few steel rods and uses cables that are laid per engineers design to carry the load. After the slab has been poured and at a specific date, the cables are pulled/stretched, sometimes twice depending on the engineers specs. They generally pull to about 35 KIPS or 35,000 pounds of force. The principle is like you picking up 10 chalkboard erasers at one time by squeezing them together. The bricks sit on what is called a brick lug. The lug is 1 1/2" below the floor level of the house. This allows any rainwater to accumulate, as brick does not stop water, and run out of weepholes that should be spaced about every third brick. It's extremely important that if you have a pest control company doing monthly treatments that they are not sticking anything in the weepholes or expect drainage issues. Because you apparently have significant topo, that means the ground has a lot of slope, the foundation was poured to have the brick lug at different levels. This saves the builder brick costs. Once the brick is installed, the foundation company comes back and puts a coat of plaster on the side of the slab for cosmetic reasons. Normally the plaster guy gets it too high and rolls it to the bottom of the brick where it cracks and looks ugly. It's suppose to be rolled over at the brick lug, about an inch difference. But it's irrelevant as it's only cosmetic.
You asked if the foundation might be a pier and beam. I doubt it. Pier and Beam is actually the best type of construction for our clay soils but they are expensive. Frankly, because of the factors in determining the appraised value of the property, a builder can't afford to use a Pier and Beam foundation. While I'm not totally familiar with Perry Homes, they were using Post Tension years back. I would think that they still are so it's a good bet that a post tension is what you have.

[steve807]

Yep, I'm familiar with post tension slabs but never knew the details about the brick lug. Looks like I've got about 3 ft (high) of brick lug at the back of my house and I did not realize that was possible for it to be that high off the slab. Was it poured at the same time the slab was ?

I did some work years ago on some very expensive houses in the Houston area and of course they were all pier and beam and I really did not expect my reasonably priced house to have that superior support system. Just could not square in my head the flat slab and 3 ft dead space before the bricks started around back.

Anyway my next project is to fix the broken plaster spots and maybe paint it all.

Thanks for the good information.