Basement paint calculator
Basements are large, low, and sensitive to moisture. A typical 24 × 20 ft finished basement has ~660 sq ft of paintable wall area — about 2 gallons for two coats. Use a paint with mildew resistance, and check the slab for vapor before painting block walls or floors. Light colors expand the space; the low ceiling is a bigger constraint than the floor plan.
Estimates round up to the nearest quart and are based on Kompozit's published coverage. Buy slightly more for touch-ups and color changes.
Recommended finish: eggshell
Block walls vs. drywall
Concrete block (CMU) walls eat ~30% more paint than drywall — block soaks paint into the joints and pores. Add 25–30% to the gallons if your basement is unfinished block. For drywall basements, this calculator is accurate.
Vapor barrier check
Tape a 2' × 2' plastic sheet to the wall for 24 hours. Condensation under it = vapor coming through. Fix the moisture (interior drainage or vapor-barrier paint) before applying topcoat — otherwise paint will bubble and peel within a year.
FAQ
In a low-ceiling basement, painting walls + ceiling the same light color visually disguises the ceiling height. Stark white ceilings emphasize "this is a basement"; matching off-white walls + ceiling makes the space feel taller.