Measure the true area
Length × width gives the base area. Pitched roofs are adjusted for slope so you do not buy for the footprint alone.
Free South African waterproofing calculator
Waterproofing calculator.
Plan before the rain.
Estimate the area, material quantity and installed cost for your roof, balcony, wall or wet area—in under two minutes.
Start your estimate ↓Free. No email required.
✓Material estimateIncluding allowance
✓Pack recommendationKnow what to buy
✓Installed cost rangePlan your budget
✓Clear assumptionsNo hidden maths
01
Your project
What needs waterproofing?
Choose the closest match. Your result will explain what is—and is not—included.
03
The method
How the estimate works
A useful estimate separates surface area, system usage and preparation—because cheap quotes often hide one of them.
Apply system coverage
Each membrane has a different consumption rate. The calculator applies the selected system and the number of required coats.
Allow for real conditions
Overlaps, corners, rough surfaces and failed coatings increase both material and preparation time.
Round to usable packs
The material estimate is rounded up to a practical pack size so the job is not left short halfway through.
A calculator measures. An expert diagnoses.
The damp patch is not always where the leak starts.
Water can enter through a parapet, joint, roof screw or cracked coping and travel before it appears indoors. Treating only the visible mark often means paying twice.
Request an assessment →Good to know
Waterproofing calculator FAQs
How accurate is this waterproofing estimate?+
It is a planning estimate based on the dimensions, selected system, surface condition and allowance you enter. Final quantities and pricing depend on moisture source, substrate, falls, detailing, access and the product specification confirmed on site.
Does waterproof paint stop an active leak?+
Not reliably on its own. Active leaks usually require correct diagnosis, repair of cracks or failed details, suitable preparation and a compatible membrane system. Coating over trapped moisture can blister or peel.
Why does surface condition affect the price?+
Failed coatings may need to be stripped. Cracks, loose screeds, damaged plaster, ponding and wet substrates require repair or drying before a new system can perform properly.
Are scaffolding and structural repairs included?+
No. The range assumes ordinary residential access. Scaffolding, rope access, replacement screeds, structural work, tiling and hidden damage should be separately identified in a written quote.