What Sand Goes Back Into Block Paving After Jet Washing?

Standard concrete or clay block paving takes kiln dried jointing sand, and Marshalls sells a block paving sand for exactly that job. The two decisions that actually go wrong on a real drive are colour and paving type. Marshalls lists its block paving sand in red for standard block paving and golden for use with lighter coloured products, so the colour has to be picked against the blocks before anything is brushed in. Permeable block paving is the other trap: its joints are filled with an angular aggregate rather than sand at all, and putting sand in them works against the way the surface is designed to drain.

That is the short answer. Below is what the colour of the sand does on light blocks, how to tell whether your paving is permeable, how to check whether a brush in jointing compound suits a driveway joint, and what the published UK price guides say re-sanding costs. If what you want to know is whether the cleaning itself will harm the paving, and what the re-sanding process involves step by step, that is covered on our guide to whether pressure washing will damage block paving.

What sand do you use after jet washing block paving?

Kiln dried jointing sand, brushed into the joints once the surface is dry. Marshalls publishes it as Block Paving Sand and supplies it in 25kg bags or 1 tonne bulk bags, so a small drive is a bag or two job and a large one is worth buying in bulk. MyBuilder's driveway cleaning cost guide describes the same material from the homeowner's side: pressure washing removes the kiln dried sand between joints, which needs to be replaced to keep the blocks stable and prevent weed regrowth. That is the whole point of the job, so the sand is not an optional extra at the end of a wash.

What colour kiln dried sand should I use on light coloured blocks?

Golden, on Marshalls' own listing. Its Block Paving Sand page gives the sand in two colours and says what each one is for: red is available for standard block paving, and golden is available for use with lighter coloured products. That is the rule to work to. If the blocks are buff, silver, cream or a light grey, the golden sand is the one Marshalls points at, and a bag marked red is not automatically the right bag just because it is the one on the van.

There is a stronger warning on this subject, and it is only honest to quote it with its scope attached. Marshalls' driveway paving technical information cautions that red kiln dried sand can cause staining to occur, especially on lighter materials. That caution sits under Marshalls' heading for Drivesett Argent Priora, Drivesett Tegula Priora and Modal X Priora, and the advice printed with it is addressed to Modal X products. Priora is Marshalls' permeable range, so the caution is published for one product family inside its permeable products, not as a general statement about standard concrete blocks. Marshalls publishes no equivalent staining warning for standard block paving, and we are not going to invent one for it.

Read narrowly it still tells you something useful, because a named manufacturer has seen red kiln dried sand stain lighter material badly enough to warn about it. So ask what colour is going in before it goes in, and ask for the golden sand if your blocks are light. The advice inside that Priora passage is a generic standard silver kiln dried sand on all Modal X products, and silver is not one of the two colours in Marshalls' own block paving sand range, so do not assume a supplier stocks it. Modal X Priora is also a permeable product, which is its own reason to read the next section first.

What if my block paving is permeable?

Then sand is the wrong material entirely. Permeable block paving is built to let rainwater pass down through the surface rather than run off it, and the joints are a working part of that system. Interpave, the precast concrete paving association, states that in concrete block permeable paving an angular aggregate of 2/6.3mm, and not sand, is used to fill the enlarged joints and as a laying course. Brush kiln dried sand into those joints and you are filling a drainage path with a fine material chosen precisely because it packs tight. That is the opposite of what the surface was designed to do.

If there is any doubt at all about which type you have, find out before anything is brushed in rather than after. These are the things that give it away.

• Joint width: Interpave describes permeable paving as having enlarged joints, so the gaps look noticeably wider than a standard drive.
• What is in the joint: it looks like fine grit or small angular stone, not smooth sand.
• How rain behaves: water disappears through the surface rather than running to a gully or off the edge.
• Paperwork: the original invoice or block name will say permeable, or name a permeable range such as Marshalls' Priora.
• Tell your cleaner: it changes both the cleaning approach and the material that goes back in.

Can I use a jointing compound instead of sand on block paving?

Check the tub against your joints before you buy one. Brush in jointing compounds are a genuinely good product and they get suggested a lot online as the permanent fix for sand washing out, but every one of them is sold against a joint width and a joint depth printed on the pack, and those figures are what decide whether it suits your paving. We are not going to name a compound as wrong for your drive without its own data sheet in front of us. Read the width and depth off the pack, then go and measure a joint.

The reason that usually settles it is that a block paving joint is narrow. Marshalls' driveway paving technical information recommends a joint width within 2 to 5mm for its Infinia Driveway range, and where it does give general joint widths they are 5mm for its sawn setts and 10mm for cropped setts and natural stone setts. Marshalls' own answer for the blocks themselves is a sand rather than a compound: it publishes Block Paving Sand in red for standard block paving and golden for lighter coloured products. So on a block paved drive the answer really is sand. On a slabbed patio with wider joints a compound may well be the better material, but that is a different surface and a different job.

What re-sanding costs, and where the published guides disagree

Two of the UK price guides publish a rate for this, and they do not agree. MyJobQuote's driveway sealing cost guide, read on 31 August 2026, prices joint re-sanding at £2 to £3 per square metre and puts kiln dried sand itself at around £1 per square metre. On the same page it prices pressure washing separately at £2 to £5 per square metre, which tells you the two are treated as distinct pieces of work rather than one bundled price.

MyBuilder's driveway cleaning cost guide, read on 31 August 2026, prices the same work lower. It says block paving re-sanding, often needed after a deep clean to restabilise the joints, adds around £1.50 to £2.50 per square metre, and its cost table lists re-sanding block paving joints at £1.50 to £2.50 per square metre. The same guide makes a point that matters more than the number: for block paving, always confirm whether re-sanding is included in the quote, because pressure washing removes the kiln dried sand between joints, which needs to be replaced to keep the blocks stable and prevent weed regrowth. Its own FAQ on the best way to clean a block paving driveway describes the standard approach as a pressure wash followed by re-sanding the joints, with a sealant after the re-sanding locking the sand in, and says attempting it without re-sanding leaves the blocks unstable and allows weeds to recolonise quickly.

So the two ranges genuinely differ. They overlap between £2 and £2.50 per square metre, but MyBuilder's floor sits a quarter below MyJobQuote's and MyBuilder's ceiling sits below MyJobQuote's. Neither page states a VAT position anywhere in the figures quoted here, so treat both as VAT-unclear rather than assuming either includes it. Neither is a quote for your driveway, and neither is our price. They are published national ranges, given here so you can sanity check what you are told. What a full block paving clean costs, and how re-sanding sits inside that, is set out on our guide to what block paving cleaning costs in the UK.

What to ask before anyone starts

• Which sand is going in, and what colour is it? Ask directly if your blocks are light coloured, and ask what the supplier actually stocks.
• Is my paving permeable? If it is, the joints need an angular aggregate rather than sand, on Interpave's guidance.
• When will it go in? Sand only fills a joint properly once the surface is dry, which is not the same day.

You can see how we approach a drive clean on our driveway cleaning page, and if sealing has been mentioned to you as well then our guide on whether to seal a patio or driveway after cleaning covers whether it is worth it at all.

What if more sand does not fix it?

Sand solves a sand problem, not a construction problem. If blocks rock underfoot, if there is a dip where the car turns in, or if the edge course has drifted outwards and opened a gap along the boundary, the sub-base or the edge restraint has moved. Refilling the joints on top of that will look better for a while and then go the same way, because nothing underneath has changed. That section needs lifting and relaying, which is a paving contractor's job, not a cleaning one.

The other thing sand will not fix is staining. Black spot lichen, oil and ingrained algae are surface problems that need the right treatment rather than a full joint, and a drive left a long time may need both. How often it needs doing at all is covered in our guide on how often to clean a driveway or patio. The point of re-sanding is narrower than people expect: it puts back what the wash took out, so the blocks stay locked together and the weeds have nowhere to sit.