Finishing
Tile and stone sealer quantity
- where
- sealer needed (litres)
- area to seal (m²)
- number of coats
- coverage per litre per coat (m²/litre)
- containers to buy
- container size (litres)
Explain this equation
Works out how much impregnating sealer to buy for natural stone, terracotta or unglazed porcelain.
A is the area, n the number of coats and Cs the coverage per litre for each coat from the product data sheet. V is the litres needed and N the containers of size Vs.
Sealer use rises with the area and the number of coats and falls as the coverage per litre rises, so the litres are A times n divided by Cs. Rounding up gives whole containers.
Sense check: 15 m² of honed porcelain at 5 m² per litre is 3 litres; a porous tumbled stone at 2.5 m² per litre would need 6 litres.
Watch out: coverage depends heavily on porosity. Test on a spare tile first.
Litres of impregnating sealer for natural stone, terracotta or unglazed porcelain from the published coverage rate.
Enter your values to see the result.
Good to know
LTP quote 1–2 litres per 10 m² (5–10 m²/litre) on lower-porosity surfaces and 3–4 litres per 10 m² (2.5–3.3 m²/litre) on higher-porosity surfaces, with at least two hours between coats and more coats on absorbent floors. Do a water drop test on a spare tile first. Pre-grout sealing of porous stone uses extra.
Common mistake
Using the low-porosity coverage on tumbled limestone or terracotta, which can drink two to three times as much.
Limits
Coverage varies widely with porosity and product. Use your product’s data sheet and test area.
Sources
Results are calculations from the published methods and manufacturer figures shown, and depend on the data you enter. Always follow the tile, adhesive and grout manufacturers’ instructions, BS 5385 and the Tile Association guidance. Coverage rates vary by product and substrate. Check prices and VAT rules with your own records and HMRC.