Cover the wall that sees water
Exterior waterproofing is usually sold by the square metre (or roll). Perimeter times cover height gives wall area; subtract large openings; add waste for laps, corners, and damage. Always follow the manufacturer’s system for footings, penetrations, and protection board.
Canadian climates freeze–thaw and drive water against foundation walls. Pair membrane numbers with proper drainage (weeping tile) and grading — this tool only sizes surface product.
Rolls, sheets, and liquid
Enter coverage per roll or pail from the technical data sheet. If the label is only in square feet, divide by 10.764 for m². Dimple board, protection board, and fasteners are separate line items on your quote.
Frequently asked questions
- Is this waterproofing calculator free?
- Yes. Free to calculate, print, share, and save with an account.
- Interior or exterior?
- The math is the same for wall area. Exterior systems dominate new builds; interior systems need different detailing — always follow the product and local code.
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