A precast basement foundation is a set of insulated concrete wall panels built in a factory and set on your lot by crane. The walls arrive with insulation, drywall studs and wiring access already in place, so the basement is warmer, drier and easier to finish.
What comes built into a precast basement wall
- Insulation. The Xi wall has 2-1/2 inches of insulation for an R-value of 12.5, and its corners, studs and bond beams are insulated too.
- Stud facings. Drywall attaches to the wall with screws.
- Wiring access. Electrical runs without drilling into concrete.
- Window and door openings. Openings are cast in to match your plans.
Why precast basements stay dry
The panels use a low water-to-cement ratio concrete that needs no additional dampproofing in U.S. markets, according to ICC evaluation report ESR-1662. Joints between panels are sealed with a polyurethane sealant made for precast concrete, and the limited warranty covers sidewall water penetration.
Finishing your precast basement
- Use at least 1/2-inch drywall.
- Attach it with 1-inch fine-thread drywall screws and a bead of construction adhesive on the top bond beam.
- Leave a 1/2-inch gap between the floor and the bottom of the drywall.
- If you add insulation, use closed-cell products.
More finishing answers are on our FAQ page, and our guide covers whether a precast basement foundation is worth it.
How a precast basement goes in
KOI designs the panels from your approved plans and casts them in the factory. The site gets a crushed stone footing, then a crane sets the panels. A typical home installs in less than one day. Framing and the floor slab go in before backfill. You can see projects on our Our Work page.
Precast basement foundations from KOI Superior Walls
KOI Superior Walls designs your basement walls from your plans, builds them and installs them across Kentucky, Ohio and Indiana, including Greater Cincinnati.
Start your basement plan or call 859-334-1130.
Common questions
What is the R-value of a precast basement wall?
The Superior Walls Xi wall is R-12.5 with 2-1/2 inches of insulation.
Do precast basement walls need extra dampproofing?
No additional dampproofing is needed in U.S. markets, according to ICC evaluation report ESR-1662.
Can I add a window or door later?
Yes, after an engineering review of point loads, bearing walls and frost protection. Talk to your KOI rep and consult an engineer first.
Can a modular home go on a precast basement foundation?
Yes. A modular home can be set on the walls right after installation.