Foundation Waterproofing Cost Estimator

• Wall area: A = Perimeter × Height
• Waste factor: W = 1 + (Waste% ÷ 100)
• Membrane cost: Cm = A × UnitCost × Coats × W
• Add-on area costs: Ca = A × AddOnUnitCost × W
• Perimeter drain: Cd = Perimeter × CostPerLength
• Excavation volume: V = Perimeter × Height × TrenchWidth
• Labor hours: H = (A ÷ Productivity) × Coats + allowances
• Labor cost: Cl = H × LaborRate × DifficultyFactor
• Direct cost: D = Materials + Earthworks + Labor
• Grand total: T = (D + O&P) + Tax

1. Select your unit system and enter perimeter and waterproofing depth.
2. Choose the waterproofing system and set coats if applicable.
3. Include primer, protection, drainage, and excavation as needed.
4. Adjust access difficulty and substrate condition for realism.
5. Enter labor rate, overhead/profit, and tax to match your market.
6. Turn on overrides to use your supplier pricing and crew production.
7. Press Calculate Cost to show results above the form.
8. Download CSV or PDF for sharing and recordkeeping.

Scope and measured wall area

Foundation waterproofing budgets start with a dependable takeoff. This estimator uses perimeter multiplied by waterproofing height to represent exterior wall area. Enter the full run around the structure, then the depth to be treated, including any exposed stem wall above grade. Use the waste allowance for overlaps, laps, and cutoffs. Include returns at steps, window wells, and utility sleeves where applicable. When units change, keep pricing inputs consistent with the selected system.

System choice and coat assumptions

Different systems price and install differently. Liquid-applied and cementitious options scale with coats, so higher build increases material and labor hours. Sheet and bentonite systems are treated as one layer because laps and fasteners drive cost more than thickness. Polyurea is modeled as coat-based to capture production limits and mobilization effort. If supplier quotes vary, enable overrides for job-specific costs.

Drainage, protection, and crack work

Add-ons can dominate the final number on wet sites. Primer improves adhesion on dusty or porous substrates. Protection boards reduce damage during backfill and help maintain continuity at corners. Drainage board and perimeter drains manage hydrostatic pressure, often reducing call-backs. Crack repair is priced per length to cover routing, injection, patching, and detailing at penetrations.

Excavation, access, and substrate condition

Excavation is estimated using perimeter times height times trench width, producing a planning volume. Haul and backfill rates apply to that volume, while excavation labor hours follow soil productivity. Access difficulty multiplies labor hours to reflect tight setbacks or limited staging. Substrate condition adds a repair allowance and extra time for grinding, patching, and curing between operations.

Reading outputs for bids

The results separate materials, earthworks, labor, and markups so you can defend a price. Review unit cost per area to compare methods across projects, then adjust overhead, profit, and tax to match your policy. Export the CSV for spreadsheets and the PDF for client review. Use overrides to reflect crew size, equipment, and seasonality. Verify manufacturer details and disposal rules before procurement.

1) Should I measure interior or exterior perimeter?

Use the exterior perimeter of the foundation wall being treated. If only one elevation is waterproofed, enter the total length of that wall run instead of the full building perimeter.

2) How do I pick a trench width?

Select a width that reflects safe working clearance for cleaning, repairs, and membrane installation. Narrow urban sites may be smaller, while deep basements often require more room for access and shoring.

3) Why does condition change both cost and hours?

Poor surfaces require cleaning, grinding, patching, and longer cure times. The calculator adds a repair materials allowance and extra labor so estimates reflect prep work, not just membrane application.

4) When should I include drainage board?

Include it when backfill is coarse, when waterproofing needs protection, or where drainage improvement is needed. It can also help extend membrane life by reducing abrasion and standing moisture.

5) Are the default unit costs reliable?

They are baseline planning values. Local labor, supplier pricing, wall height, and detailing can change totals significantly. Turn on overrides to enter your real costs and productivity rates.

6) What does unit cost per area help with?

It lets you compare systems fairly across different building sizes. Use it to benchmark bids, test “what-if” add-ons, and confirm that markups produce a sustainable margin.