Patio Care: The Complete Guide

Patio stone types and how they clean differently

Indian sandstone, one of the most common patio materials in the UK, is porous and can be prone to both algae growth and, notoriously, black spot lichen, and generally responds well to pressure washing followed by a specific biocide treatment for lichen. Limestone is softer and can be more sensitive to acidic cleaning products, which can etch the surface, so a pH-neutral approach is usually safer.

Concrete flags tolerate pressure washing robustly and rarely need special treatment beyond standard cleaning, while porcelain paving, increasingly popular on newer patios, is very hard-wearing and low-maintenance but can still develop a slippery algae film in shaded, damp areas that needs occasional cleaning to keep safe underfoot.

Dealing with black spot lichen

Black spot lichen is the small, stubborn black or dark green circular growth that appears particularly on sandstone patios and is notoriously difficult to remove with pressure alone, since it bonds tightly to the stone surface and regrows from spores left behind after a purely physical clean. A specific biocide treatment, left to dwell properly before rinsing, is the standard effective approach, sometimes needing a repeat application for particularly established growth.

It's worth being realistic with anyone quoting for black spot removal: a single visit can dramatically improve it, but genuinely stubborn, long-established lichen sometimes needs a follow-up treatment a few weeks later to fully clear, and any contractor promising instant, guaranteed total removal in one pass on a bad case isn't being entirely straight with you.

Should you seal your patio?

Sealing a patio after cleaning protects the surface from staining, makes future cleaning easier, and can slightly enhance the stone's natural colour depending on the product used. It's particularly worth considering for sandstone patios with a history of black spot lichen, since some sealants make it noticeably harder for lichen spores to establish, extending the time between treatments.

It's not essential for every patio, and porcelain paving in particular often doesn't need sealing at all given how non-porous it is, so it's worth asking whether it's genuinely beneficial for your specific stone type rather than being sold it as standard on every job.

What patio care typically costs

Patio cleaning is typically priced per square metre, commonly around £3 to £6, with black spot lichen treatment on sandstone sometimes priced as an add-on given the extra biocide product and dwell time required. Sealing adds a further cost per square metre but extends how long the patio stays looking clean, which can be worthwhile on patios with a history of quick regrowth or heavy shade.