Natural stone sealers for patios are essential for protecting outdoor stone surfaces from moisture, staining, UV exposure and organic growth. Unlike indoor areas, patios are exposed to rain, frost and temperature fluctuations, which can lead to cracking, surface damage and discolouration if left unprotected.

More porous stones such as Indian stone, sandstone, limestone and travertine require regular sealing to prevent water ingress, while denser stones like granite typically need less frequent treatment. For long-term performance, always use a breathable, exterior-grade stone sealer designed specifically for outdoor use.

What you’ll need

Breathable natural stone patio sealer, pressure washer or stiff broom, low-pressure sprayer or roller and tray, soft-bristled broom or squeegee, 100mm paintbrush for edges, clean cloths, gloves, goggles and mask.

1. Preparation

Thoroughly clean the patio using a pressure washer to remove dirt, algae and moss.
For stubborn organic growth, use a suitable fungicidal wash.
Allow the stone to dry completely for at least 48 hours in dry conditions.
Test the sealer on a small, inconspicuous area to check finish and colour enhancement.

2. Application

Apply the sealer evenly using a roller, brush or low-pressure sprayer.
Work in manageable sections to keep the surface wet during application.
Allow the sealer to penetrate for 15–30 minutes.
Remove any excess sealer that has not absorbed using a cloth, roller or squeegee to prevent residue or whitening.

3. Second coat & curing

Apply a light second coat approximately 40–45 minutes after the first for maximum protection, removing excess again.
Avoid foot traffic for 4–24 hours depending on the product.
Allow 24–48 hours before heavy use.

Key tips

Always use a breathable, impregnating stone sealer to prevent trapped moisture and whitening.
Apply only in dry weather, ideally between 3°C and 30°C.
Stone must be completely dry before sealing to avoid cloudy marks.
Porcelain paving is non-porous and does not require sealing, though grout lines may be treated if required.
Seal porous stone before applying any jointing compound to prevent staining.
A pump sprayer followed by a roller provides the most even finish.