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Waterproofing Membrane Calculator

Updated Aug 25, 2026 Reviewed Aug 25, 2026

Estimate liquid or sheet waterproofing, primer, seam band, whole packages and cost across multiple surfaces.

Waterproofing material takeoff

Enter wet-area surfaces and verified system coverage

Waterproofed surfaces

Area 1

Area name

Area shape

Length

Width

Measurement unit

Excluded area

Area unit

Membrane system and coverage

Membrane type

Coverage basis

Choose whether the stated coverage already includes all required coats.

Required coats or layers

Coverage per container

Coverage area unit

Ordering waste (%)

Primer and seam accessories

Include primer containers

Primer coverage per container

Coverage area unit

Include seam and transition band

Include calculated surface perimeters

Additional seam, corner and penetration length

Length unit

Band length per roll

Length unit

Result units and optional cost

Area result unit

Band-length result unit

Price per membrane container or roll

Price per primer container

Price per band roll

Currency

Quantity estimate — not waterproofing design

Confirm compatible substrates, drains, transitions, minimum film thickness, cure times, flood testing and code requirements with the selected system.

Result

Calculation summary

Enter values to see the result

Your result, breakdown, assumptions, and warnings will appear here.

Assembly preview

Membrane layer and sealed transitions

Live preview

Net waterproofed area

20 m²

Band rolls

Whole membrane packages

How to use this calculator

1Add every surface and subtract known exclusions.
2Choose liquid or sheet membrane and the matching coverage method.
3Enter current product coverage, layers or roll dimensions.
4Add primer, seam band, waste and optional prices.

Formula

Packages = adjusted coverage demand ÷ verified package coverage

Per-layer liquid coverage multiplies area by layer count; sheet dimension mode reduces roll yield by the entered overlap.

Calculation steps

Combine surface areas and perimeters.
Subtract excluded area.
Apply the selected layer or roll-overlap model.
Apply ordering waste.
Round membrane, primer and band upward.

Worked example

A 20 m² surface with 10% waste requires 22 m² of completed-system coverage before packages are rounded.

Assumptions

Coverage basis matches current product data.
Roll overlap is an entered allowance.
Areas do not overlap.
Primer and band are optional separate materials.
Waterproofing design and compliance are outside scope.

Sources

Frequently asked questions

What is completed-system coverage?

The package coverage already includes the manufacturer-required coats.

When should I use per-layer coverage?

Only when the product states coverage for one coat or layer.

How are roll overlaps handled?

Use manufacturer net coverage or enter dimensions plus an explicit overlap percentage.

Can seam band include perimeters?

Yes, with optional additional measured transition length.

Does it design the assembly?

No, confirm all system details separately.

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