What Kind Of Foundation Do I Have?
Do you have a “slab on grade” foundation?..
A slab on grade foundation is ..well…just that. A poured concrete slab that sits on soil or crushed rock. It’s usually 4 to 6 inches thick, but thicker around the edges for extra strength. Embedded in the concrete is wire mesh and steel reinforcing bars. Sewer pipes and most of the electrical conduit is put in place before the concrete is poured.
“Do you have a post tensioned foundation?”
It’s a concrete slab that is reinforced with stranded steel cables that are tensioned after the concrete hardens. The stranded steel cables are slid inside a plastic sheathing, that prevents the stranded steel tendons from touching the concrete. When it’s totally dry, the plastic sheathing is stretched. Stretching the cables applies force to the concrete, lifting the slab into a compressed state, which reduces cracking.
“How can I tell if the slab is post tensioned?”
It should have a stamp on the garage floor, in plain sight. If you don’t see it, they may have posted a sign on the wall near the door that leads to the house from the garage.
It will say “POST TENSION SLAB AND FTG. DO NOT CUT OR CORE”
Ever heard the saying, “be careful or you’ll poke your eye out?” If you cut or damage the cable, because it’s under a huge amount of pressure, it can occasionally rip right out of the slab and injure someone near it.
“What is a raised foundation?"
Before your actual house was built…they started out with a footing, then a foundation wall topped with a sill plate and rim joists (exterior walls are then attached). They level out the dirt underneath and place concrete pads with wood posts that support the girder beams. The girder beams go lengthwise and the floor joists opposite way on top of those.