Help With Foundation Questions

newbie

Can some one explained the difference between Post-Tension concrete slab and a convential rebar slab. Trying to decide which to use. I live in Mississippi and the soil where I am building contains about 2 feet of silt.

Thanks,

hatchet

The post-tension slab will have tendons in the lower portion of the slab that connect to haunches located at the perimieter. The haunches are blocked out of the pour until later. Sometimes these are located at intermediate areas also, depending on size of slab. Once it's poured and the slab begins to cure the tendons are tensioned to whatever has been designed. The blockouts for the haunches are then poured back in. In 2 story or more many times the haunches will be placed in pour strips that will need to be shored up when they are poured back.
A conventional rebar slab will typically have #4 or #5 rebar placed at 12-15" on center each way in the middle of the slab. Usually held up by bolsters or rebar chairs. Slab is poured and it cures.
How that relates to silt I have no idea.. you will probably need to have an engineer get involved and have a geotechnical survey done. Most likely you'll need to have the whole structure placed on caissons embedded into bedrock or something similar.

__________________
Rich
WIT Construction Co.
Superior MT Contractor