WATERPROOFING
How Much Does Basement Waterproofing Cost?
Estimate basement waterproofing cost per square foot of wall — interior, exterior and drainage — with the free calculator.
A wet basement is one of the most stressful problems a homeowner faces, and the fix ranges from a simple coating to full exterior excavation. This guide covers the cost per square foot and a calculator to price the job.
THE SHORT ANSWER
The short answer
Interior waterproofing runs $3–$8 per sq ft of wall; exterior $5–$12 per sq ft. Most basements cost $5,000–$15,000 total, plus $50–$150 per linear foot for drainage systems.
Interior vs. exterior treatment
Interior waterproofing — sealants, membranes and drainage board — is cheaper and handles most seepage. Exterior waterproofing is more effective against hydrostatic pressure but requires excavating around the foundation, which is most of the cost.
- Interior coating: $3–$8 per sq ft
- Exterior membrane: $5–$12 per sq ft
- French drain (interior): $50–$100 per linear ft
- Exterior drainage: $100–$150 per linear ft
The drainage is the long-term fix
Coatings stop damp walls, but standing water outside still finds a way in. An interior French drain or exterior drainage system collects water and moves it to a sump pump or daylight. That's what keeps a basement dry for decades.
Root causes change the quote
The cheapest fix is a wet basement from condensation or minor seepage. Cracks, bowing walls, poor grading and a high water table all push the price up. Get the cause diagnosed before paying for a fix that won't hold.
Try the calculator with your basement
Enter the wall area, treatment price per sq ft and labor per sq ft to see the total.