Ask DS: New home construction

[stitch]

New home construction, would you build on a slab or conventional foundation?

[southernvaughan]

Slab. I've wieghed the options of both. A deep footed footed slab cut out on the front and partially the sides to give it the raised look is the way to go! Just has to be on good dirt that's been properly compacted.

[bowbird]

We just moved into our new home a month ago. When we were talking with the contractor he suggested a raised slab. It is 3 blocks high with the dirt backfilled and then the slab is poured. We are very pleased.

[stitch]

....I always thought a slab was the way to go....where I live the soil has a history of "moving"....lots of houses with foundation issues....so I am leaning towards conventional because it would be easier to correct issues /shifting on conventional vs slab....but I really like a slab

[southernvaughan]

A slab will be fine as long as you get the soil tested and take the right measures to ensure you aren't building on expansive clays and get it packed correctly. The one I'm building now is on a 5.5 inch slab but I had the outside footings dug down about 5 foot and made them 24" thick. Then you cut out the grade wherever you want it to look raised. You will still have problems with either one if you don't get the dirt right. Conventional is a lot more expensive to build as well and you have to fight moisture problems. These days on conventionals they pour a 2" mud slab then build the conventional up over that.

[duckter]

Conventional Stitch - conventional.

[stitch]

Conventional Stitch - conventional.

I have a buddy in Germantown and one in Birmingham that are builders.....they both said slab.....as you know, I have walked into too many houses in Corinth with foundation issues.....they can't give those houses away

I "get" the concept of proper foundation and you won't have issues with a slab....but have concerns with what I have heard about soil in this area

For what it's worth.....2 houses being built near my lot, both are on slabs

What to do.....

[novacaine]

Slab on grade beams is and will always be my suggestion.
You only have one chance to get it right so start out right.
I have seen conventional, thin slab, post tension, etc but the grade beam (exterior footing) with interior smaller beams on 16 ft to 20 ft centers will overcome many issues that you encounter during the life of a home.
The theory in a nutshell is this:
Changes in soil moisture content cause 99.999% of the problem with any foundation. It can be constantly wet, it can be constantly dry, but no soil on this planet can retain the same volume while going thru a 20% moisture change..............dry as heck on year, wet as heck the next, or wet then dry throughout the seasons( especially true with highly expansive clays).
Good site drainage and gutters can help most of the times but i like the grade beam design because it takes these variables out of the equation.
Conventional footings go through differential settlement by the footing strip(or pier) being wetter on one side or wall than the other parts during a wet/dry cycle. This causes differential settlement.
Conventional slabs curl up or curl down depending on the moisture content of the exterior of the house. This causes diagonal wall cracks or interior slab cracks to form.
The beauty of the grade beam (waffle slab) is that the whole thing can curl up/curl down/ corner elevate/corner settle but it all stays together.
The downside is that its a little more expensive to build due to layout and additional reinforcement in the interior beams but like i said, you only have one chance to get it right.
Just my 2 cents worth............................................

[mlj300]

I just built a house in Alcorn County and went with a conventional for several reasons. I am really pleased with it. My footing is 4 feet deep and 2 feet wide with 64 load bearing piers placed at different intervals. I have had zero problems in the first year with any kind of shifting. I have had a problrm with moisture under the house but have it under control now. I believe that both foundation types have their merits but in Alcorn county or the city of corinth (ecspecially the nort side) a conventional will hold up a little better against the crappy soil types we have. Few people around here have slab foundations without eventually having issues with setteling or cracking. Just my 2 cents

[Deltaquack]

We just moved into our new home a month ago. When we were talking with the contractor he suggested a raised slab. It is 3 blocks high with the dirt backfilled and then the slab is poured. We are very pleased.

I was told by multiple engineers to not do this. I even got a foundation design from an engineer. They all specified a monolithic slab and no blocks. Those blocks have become popular around here b/c it's cheaper for the builder. The monolithic route is a lot more concrete if you want it raised.....but exponentially stronger.

To get the raised look.......you get a pad compacted to 5.5-6 inches less that the height you want it. They still dig footings the same and such.....just deeper. The boards around the perimeter will be a lot taller as well....so requires more materials. Your garage will be lower than your slab.....so that gets a little tricky.

[southernvaughan]

Yeah in some counties around here they won't even allow the block wall style foundation.

[bhuggins]

Conventional Stitch - conventional.

I have a buddy in Germantown and one in Birmingham that are builders.....they both said slab.....as you know, I have walked into too many houses in Corinth with foundation issues.....they can't give those houses away

I "get" the concept of proper foundation and you won't have issues with a slab....but have concerns with what I have heard about soil in this area

For what it's worth.....2 houses being built near my lot, both are on slabs

What to do.....

Spend the money on an irrigation system at least around the house when you build and it will help a lot-especially in July/August/Sept when it gets so dry. That is when most of the shifting seems to occur.

[duckter]

Contact Norman Cornelius - he will provide a soil analysis for that area and assist.

[tica-tica]

if a builder is involved, get an independent home inspector to go thru it with a fine tooth comb before final payment. Best money I ever spent.

[bowbird]

We just moved into our new home a month ago. When we were talking with the contractor he suggested a raised slab. It is 3 blocks high with the dirt backfilled and then the slab is poured. We are very pleased.

I was told by multiple engineers to not do this. I even got a foundation design from an engineer. They all specified a monolithic slab and no blocks. Those blocks have become popular around here b/c it's cheaper for the builder. The monolithic route is a lot more concrete if you want it raised.....but exponentially stronger.

To get the raised look.......you get a pad compacted to 5.5-6 inches less that the height you want it. They still dig footings the same and such.....just deeper. The boards around the perimeter will be a lot taller as well....so requires more materials. Your garage will be lower than your slab.....so that gets a little tricky.

dang I guess we are stuck with it, I am definitely no expert in this area and the contractor was against conventional and he wasn't too keen on raised slab (due to extra cost and labor). Maybe living in the "red hills" of winston county will help avoid foundation issues