Short answer
Clean Indian sandstone gently: sweep, weed the joints, wet the stone, apply a cleaner labelled as suitable for natural sandstone, scrub with a stiff synthetic brush and rinse well. Avoid acid-based cleaners and bleach, and only use a pressure washer on a low setting held well back, because sandstone is soft and porous and easily marked.
Why sandstone needs extra care
Indian sandstone is a natural stone made of compressed sand grains. It is popular for its warm colours and riven texture, but compared with concrete or porcelain it is relatively soft and porous. Water, dirt and cleaning products soak into it, the surface can be worn away by too much pressure, and some chemicals react with minerals in the stone, causing discolouration or rust-coloured marks.
Every batch of stone is different, and colours vary even within one patio. That makes testing any method on a hidden area particularly important.
Step by step: cleaning Indian sandstone
- Clear the patio and sweep off leaves, soil and loose dirt.
- Rake weeds and moss out of the joints with a weeding knife or joint brush, taking care not to chip the slab edges.
- Wet the stone with a hose so the cleaner does not soak straight in.
- Apply a cleaner labelled as suitable for natural stone or sandstone, diluted as instructed, after testing it on a hidden slab and checking the result once dry.
- Leave it for the recommended contact time, keeping the surface damp.
- Scrub firmly with a stiff synthetic brush, working with the riven texture.
- Rinse thoroughly with clean water and let the stone dry completely before judging the result.
What to avoid on sandstone
Acid-based products, including many brick and patio acids and household descalers, can etch the surface and react with iron in the stone, leaving rust-coloured patches. Bleach can discolour the stone and harm nearby plants. Wire brushes scratch the surface. And very high pressure, or a pinpoint nozzle held close, can erode the softer layers, leaving a rough, pitted finish that holds dirt and turns green faster.
Never mix cleaning products, and keep run-off out of drains and ponds.
Can you pressure wash Indian sandstone?
You can, carefully. Use a low setting and a fan nozzle or rotary surface cleaner attachment, keep it moving at a steady distance, and do not aim it straight into the joints. Watch the surface: if it looks rougher or sand grains are washing off, stop. Many sandstone patios are better treated with a suitable cleaner, time and scrubbing, with the pressure washer used only for a gentle rinse.
Black spots and green growth
Sandstone's texture makes it a favourite home for lichen, which shows as small black spots that will not scrub off, and for green algae in shady areas. These need specific treatment rather than more pressure. Our guides to black spots on patios and moss and algae on patios explain how to tackle them safely. For other types of slab, see how to clean patio slabs.
Keeping sandstone looking good
Sweep regularly and clear fallen leaves before they stain. Rinse off spills such as wine, oil and barbecue fat promptly, and raise pots on feet to avoid rings.
Some people seal sandstone to make it easier to keep clean. If you are considering it, the stone must be thoroughly clean and dry first, and it is worth testing the sealer on a spare offcut or hidden area, as some change the colour of the stone.
When to call a professional
Because mistakes on sandstone can be permanent, it is worth calling a professional if the patio is heavily stained or covered in black spots, or if you are unsure which products are safe.
When we clean Indian sandstone, we use controlled pressure and suitable treatments to avoid damage and treat delicate stone with care. A biocide treatment can be applied afterwards to help slow green growth returning.
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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 cleaner for Indian sandstone?
A cleaner that is specifically labelled as safe for natural stone or sandstone. Avoid acid-based products and bleach, and test any product on a hidden area first.
Can you pressure wash Indian sandstone?
Yes, but only on a low setting with a fan nozzle or rotary attachment, kept moving and well back. Too much pressure can erode and roughen the stone.
Why has my sandstone gone orange after cleaning?
Rust-coloured marks can appear when acid-based or unsuitable cleaners react with iron in the stone. Stop using the product and get advice before trying anything else, as some treatments can make it worse.
Related guides
- How to clean patio slabs: the general method for most patios, when a pressure washer helps and when it does more harm than good.
- 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 clean a porcelain patio: everyday cleaning for dense porcelain tiles, with most of the attention on the joints where dirt and growth collect.