Slab foundation building in Mobile AL - planned around your lot's flood zone

A concrete slab in Mobile usually costs about $5.50 to $10.50 per square foot, and that's the going rate around here for the slab, not our price. Where yours lands depends on the drivers I covered above, plus extras like a pre-construction termite treatment. Your written estimate breaks each piece out so you can compare it with any other bid.

Often you can, but the flood zone decides how the foundation is built. FEMA's guidance says homes in an A zone need the lowest floor above the base flood elevation, the flood height the maps plan for, and V zones need pile or other open foundations so floodwater passes under the raised house. In a Coastal A Zone, the state's floodplain guide recommends those same raised methods, so ask whether a raised foundation suits your lot. The city also requires Elevation Certificates from an engineer, architect or licensed surveyor at several stages of the build, and the final one has to be approved before anyone can move in. You can look up your lot's designation on the FEMA flood map through the City of Mobile's flooding page.

Almost certainly, yes. Mobile County says almost any residential or commercial work needs a county permit, and inside the City of Mobile, permits go through Build Mobile and its online portal. One of the city's permit checklists asks for a structural and foundation plan, so ask anyone bidding your job who draws that plan.

Have the ground treated before the slab goes down. Liquid termiticides, chemicals that keep termites out or kill them, can go into the soil under and around a house before or after it's built, and treating before the pour puts that barrier under the whole house from the start. That matters here because Formosan subterranean termites, some of the worst home wreckers there are, are most common in hot, humid coastal counties like Mobile and Baldwin.

For the bigger parts of the job, yes. If you build under the homeowner exemption, the state's Home Builders Licensure Board says any subcontractor whose part costs over $10,000 has to be licensed. Check that before you sign with anyone pouring your slab.

Start with a dug-out, packed base and good drainage, because most bad cracks come from ground that moves or stays wet under the concrete. We set rebar, steel bars that hold the concrete together if it does crack, and cut control joints, shallow grooves that give the slab a straight place to crack, before the concrete sets too hard. Concrete still cracks some, but pouring in the cooler hours and letting it cure, staying damp while it gains strength, keeps the top hard and the cracks where we chose.