Waterproofing calculator: work out slurry and liquid membrane
How much waterproofing slurry or liquid membrane do you need? Enter the area and choose a product – the calculation uses the minimum layer thickness from the product's data sheet.
–kg
Calculation:
area [m²] × minimum layer thickness [mm] × consumption [kg/m² per mm], at least the minimum application quantity according to the data sheet, + 10 % allowance (rough substrate: 15 %; both allowances are empirical values from processing, not data sheet figures), rounded up to whole containers. With pressing water or rough masonry the data sheet requires a greater layer thickness.
Guide value according to the manufacturer's data sheet, as of 01.10.2026. Matching products
Ottoflex liquid membrane 7kg bucket
7 kg bucket · €50.49 · Choose colour/version
Matching guides
All guides
Instructions
Guide: applying waterproofing slurry
Apply waterproofing slurry in thin coats crosswise, with sealing tape at corners and connections
Basics
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Instructions
Guide: waterproofing a bathroom with liquid membrane
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Comparison
Guide: waterproofing slurry or bitumen – what belongs where?
Waterproofing slurry or thick bitumen coating: which waterproofing goes where
Instructions
How to: waterproof a shower with liquid membrane and sealing tape
Waterproof the shower before tiling with liquid membrane, sealing tape and collars
The usage of a waterproofing layer depends on the coat thickness the product's data sheet requires – not on a rule of thumb. This calculator therefore works per product with that product's minimum coat thickness and its usage per millimetre, each with a source.