Short answer
The best way to clean patio slabs is to sweep them, remove weeds from the joints, apply a patio cleaner suited to the stone, scrub with a stiff brush and rinse thoroughly. A pressure washer speeds things up on hard-wearing concrete slabs, but natural stone and pointed joints need a gentler approach. Identify your paving first, because the right method depends on the material.
Know what your patio is made of
Concrete slabs are hard-wearing and tolerate most patio cleaners and careful pressure washing. Natural stone, including Indian sandstone, limestone and slate, is softer and more porous, and can be marked by acids, bleach and high pressure. Porcelain is very dense, so dirt sits on top and comes off easily, but the joints still need care.
If you have sandstone or porcelain, our guides to cleaning Indian sandstone and porcelain patios go into more detail. This guide covers the general method that suits most slabs.
Preparation
Clear furniture, pots and the barbecue off the patio, then sweep thoroughly to remove leaves, soil and loose debris. Check the joints: note any loose or missing pointing and any slabs that rock, because water and scrubbing can make these worse.
Cover plants and lawn edges if you are using a cleaning product, and make sure water can drain away from the house rather than pooling against walls or air bricks.
Step by step: cleaning patio slabs
- Pull weeds and moss out of the joints with a weeding knife or joint brush.
- Wet the slabs with a hose so the cleaner spreads evenly and does not soak straight in.
- Apply a patio cleaner that is suitable for your stone, diluted as the label instructs, after testing it on a hidden slab.
- Leave it for the contact time the manufacturer recommends, keeping it damp.
- Scrub with a stiff broom or deck brush, working in sections.
- Rinse thoroughly with clean water, by hose or pressure washer, working away from the house.
- Let the patio dry fully and inspect it in daylight before deciding whether any area needs a second treatment.
Should you use a pressure washer?
A pressure washer is the quickest way to rinse dirt and loosened growth from robust concrete slabs. Use a fan nozzle or rotary surface cleaner attachment, keep it moving at a low angle and a steady distance, and avoid aiming straight into joints, which can blast out pointing or sand. On natural stone, use a lower setting or skip it altogether; too much pressure can roughen the surface and open it up to more dirt.
If you would rather not use one at all, a patio can be cleaned very effectively by hand. Our guide on how to clean a patio without a pressure washer explains how.
Problem marks
General cleaning lifts dirt and most green growth, but some marks need their own approach. Small black dots that will not scrub off are usually lichen; see our guide to removing black spots from a patio. Thick moss and slippery green algae, common in shaded corners, are covered in our guide to moss and algae on patios.
Aftercare
Once the patio is clean and dry, re-point any joints that have lost mortar, or top up sand joints with kiln-dried sand. Sweep regularly, clear fallen leaves promptly and keep pots raised on feet so water does not sit underneath and leave rings. Patios in shade turn green again sooner than those in sun, so a lighter clean more often is easier than a big job once in a while.
When to call a professional
Call a professional if the patio is large, heavily stained or made of natural stone you are worried about damaging, or if the joints are already loose. A professional can match the method to the stone and clean evenly across the whole area.
When we clean patios, we use rotary surface cleaners for an even finish, adjust the pressure and technique for sandstone, porcelain, concrete and natural stone, remove weeds and moss from the joints and point out any loose pointing. A biocide treatment can be added afterwards to help slow regrowth.
Rather have it done for you?
Sandstone, porcelain, slabs and decking brought back to life. Family-run by Jason and Lucas Prior, covering south Essex.
Frequently asked questions
What is the best thing to clean patio slabs with?
A patio cleaner that is suitable for your type of stone, applied as the label directs and scrubbed in with a stiff brush, then rinsed off thoroughly.
Can I use bleach on my patio?
It is best avoided, particularly on natural stone, where it can cause discolouration, and near plants and lawns. Never mix bleach with other cleaning products.
How often should a patio be cleaned?
Sweep it regularly and give it a proper clean when green growth or dirt starts to build up. Shaded patios usually need attention more often than sunny ones.
Related guides
- How to clean a patio without a pressure washer: a hand-cleaning method that relies on the right cleaner, a good brush and a thorough rinse instead of water pressure.
- How to remove black spots and lichen from a patio: why black spots survive scrubbing and pressure washing, and how to treat lichen without damaging the stone.
- How to get rid of moss and green algae on a patio: clearing slippery green growth from paving and joints, and the shade, damp and debris that let it return.
- How to clean Indian sandstone: gentle cleaning for soft, porous sandstone, the products that can stain it and how to use a pressure washer safely.
- How to clean a porcelain patio: everyday cleaning for dense porcelain tiles, with most of the attention on the joints where dirt and growth collect.
- What affects the cost of driveway and patio cleaning: the factors that change a driveway, patio or jet washing quote, including surface type, condition, re-sanding and sealing, and how to compare quotes.