Foundation Waterproofing / Dampproofing Takeoff
The fluid-applied waterproofing or dampproofing to coat a below-grade foundation wall.
Example
You enter
- Foundation perimeter (ft) 150
- Average below-grade height (ft) 8
- Coverage per coat (sf/gal, from the data sheet) 50
- Waste (percent) 10
You get
- Below-grade wall area 1,200 sf
- Gallons 27
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
Scopearea = perimeter x average below-grade height; gallons = ceil(area x (1 + waste) / the product's coverage rate). A 150 ft perimeter, 8 ft below grade is 1,200 sf, so at 50 sf/gal spray-applied with 10% waste it takes 27 gallons (6 five-gallon pails). The coverage rate is the lever and varies widely: emulsion DAMPPROOFing runs ~70-100 sf/gal per coat sprayed, 40-50 brushed in two coats (a moisture barrier, IRC R406.1), while a fluid-applied WATERPROOFing membrane built to a wet-mil thickness (for hydrostatic head, IRC R406.2) covers far fewer sf/gal per coat and often needs two coats plus reinforcing fabric -- read it off the data sheet, not a default. Sheet peel-and-stick membrane is ordered by the roll instead. A material-ordering estimate; the product data sheet, the assembly detail (drainage board, footing drain), and IRC R406 and the AHJ govern.
Formula or tablewall_area_sf = perimeter_ft x below_grade_height_ft; gallons = ceil(wall_area_sf x coats x (1 + waste_pct/100) / coverage_sf_per_gal); pails_5gal = ceil(gallons / 5).
Source and editionFoundation waterproofing / dampproofing material takeoff (area x coverage), by name; IRC R406 (dampproofing vs waterproofing) and the product data sheet and AHJ govern.
Free accessThe takeoff is public first-principles (wall area over the product coverage rate); the coverage rate comes from the product data sheet and the dimensions from the foundation.
What governsEstimate. AHJ and licensed professional govern.
API field namesperimeter_ft, below_grade_height_ft, coverage_sf_per_gal, waste_pct, wall_area_sf, gallons
- Area over coverage area = perimeter x below-grade height; gallons = ceil(area x coats x (1 + waste) / coverage rate per coat); pails = ceil(gallons/5)material-takeoff practice
- Dampproofing vs waterproofing coverage is per coat and varies widely: emulsion dampproofing ~70-100 sf/gal spray, 40-50 brush in two coats (IRC R406.1; W.R. Meadows) vs a fluid membrane at a wet-mil thickness (IRC R406.2); read the data sheet; sheet membrane is by the rollIRC R406 / product data sheet