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Kiln dried sand for block paving

Updated: October 2026

The joints on a concrete block drive have gone pale after a jet wash, and a few blocks tap as you walk to the bins. Kiln dried sand for block paving puts friction back into those gaps. It is not a new driveway, and it will not lift a base that has already failed. This page stays with joints of a few millimetres: why the sand is there, how a top-up differs from a full lay, and when you stop buying bags. The stroke is on [how to brush in kiln dried sand](/hub/flooring-tools-and-accessories/kiln-dried-sand/sub/kiln-dried-sand-how-to-brush-in). The seven bags are on the [Kiln dried sand](/hub/flooring-tools-and-accessories/kiln-dried-sand) comparison. A qualifying purchase can earn a commission at no extra cost to you.

The joints on a concrete block drive have gone pale after a jet wash, and a few blocks tap as you walk to the bins. Kiln dried sand for block paving puts friction back into those gaps.

Our top picks

Specialist Aggregates Specialist Aggregates light grey 15 kg

Best overall

Specialist Aggregates Specialist Aggregates light grey 15 kg
8.2/10about £32.40
View offer
Laeto Laeto kiln dried sand 20 kg

Best value

Laeto Laeto kiln dried sand 20 kg
8.0/10about £16.14
View offer
Dansand Dansand No Grow beige 20 kg

Rank 3

Dansand Dansand No Grow beige 20 kg
8.6/10about £20.39
View offer
On this page
  1. 1.What the joint is doing
  2. 2.A top-up, not a new driveway
  3. 3.Narrow blocks, not every gap
  4. 4.When another bag is the wrong spend

What the joint is doing

On a flexible block pavement the joint is part of the structure, not a cosmetic gap. The sand is the friction that lets neighbouring blocks share a load. Paving.org.uk puts it plainly: empty joints let the blocks move and let water into the laying course. Re-sanding after a clean puts that friction back, provided the bed underneath is still sound. Nothing in that joint should be cement. Tobermore keeps sharp sand, with no binder, in the laying course, and kiln dried sand in the joint. Wind and rain move unbound sand. Laeto buyers describe sand that drifts after a power wash, and Dansand reviews describe washout as well. A mineral additive does not turn the joint into a glued seam. If the sand leaves a slope after every storm, that limit is the point of the polymeric comparison.

A top-up, not a new driveway

Most re-sanding is a top-up. Pavingexpert notes that after a clean the joints are often still half or two-thirds full, so the job is gravity and a brush, not another pass with a plate. You are replacing what the jet wash pulled out of the top of the slot. A plate, with a rubber mat, belongs to new laying. Using it on a finished drive can mark the concrete without filling a joint that was still damp. Paving.org.uk gives a rough top-up of one 20–25 kg bag per 15–30 m². That is not Laeto’s listed 20 m², and not CEMEX’s about 5 m² per 25 kg for a full joint. Do not blend those figures into one guess. If you are only restoring sand after washing, dry the joints and sweep.
Specialist Aggregates Specialist Aggregates light grey 15 kg

Testsieger

Specialist Aggregates Specialist Aggregates light grey 15 kg
8.2/10about £32.40
View offer

Narrow blocks, not every gap

This sand is for a concrete block joint of about 2–5 mm. Dansand’s beige bags state up to 5 mm. The 20 kg listing, £20.39 with 3.9 from 308 reviews, pairs that width with a coverage of 5–10 m². It still does not set. The 10 kg bag at £12.32 repeats the 5 mm line and a twenty-kilogram bullet. Use it when the lift matters. A joint of about 1 mm is where grey Dansand fails in the reviews. It is £27.99 for 20 kg, with 3.9 from 698 reviews, and it states no millimetre limit. Specialist Aggregates states 0.1–0.7 mm on both 15 kg bags, at £32.40. That is a colour match, not a promise for every tight concrete joint. A permeable pavement uses a coarser grit joint, not this fine sand.

When another bag is the wrong spend

Stop when the blocks rock, the surface has sunk, or the edge restraint has moved. Sand fills a joint. It cannot lift a driveway, and another 20 kg bag will not pull a kicked-out edge back. Stop, too, when the same joints empty after every wet week and the drive is on a fall. Unbound sand will keep leaving. A curing joint is then the product to price. Do not try to get that behaviour by wetting Laeto or Dansand. For a sound block drive, dry the joints and choose the bag for grain and colour. Plain sand with 520 reviews is Laeto at £16.14. A stated 5 mm joint on a consistent 20 kg listing is beige Dansand. A granite match is Specialist Aggregates, with a short written file. If the blocks move, another bag is the wrong spend.

Common questions

Why re-sand after a jet wash?
The wash pulls sand out of the joint, and an empty joint lets blocks move and lets water into the bed. Paving.org.uk treats the refill as part of keeping the pavement locked. Wait until the joints are dry for a few days, then brush kiln dried sand back in. Filling them while they are damp leaves a hollow under a crust.
Will sand stop a driveway sinking?
No. Kiln dried sand restores the joint. It does not rebuild a failed laying course or a soft spot in the ground. If blocks have dropped, or a patch pumps water when you stand on it, adding sand on top will not lift them. That area needs to be lifted and re-laid.
How much sand is a top-up?
Paving.org.uk suggests about one 20–25 kg bag per 15–30 m² when you are only replacing sand the clean removed. Joints that are empty to the bed need more, closer to CEMEX’s about 5 m² per 25 kg. Use the figure for the emptiness you can see.
What if the joints are about 1 mm and the grey sand looks like grit?
Grey Dansand reviews describe exactly that. The grains miss a 1 mm block joint, and the listing gives no millimetre limit, despite 698 reviews. Beige Dansand states up to 5 mm, which does not help a joint that has closed to a hairline.
When do I stop and call someone?
When blocks rock, the edge has moved, or a patch has sunk. Also when you need a joint that stays put on a steep fall and you are about to water kiln dried sand in the hope it will cure. A tradesperson can re-lay the failed area. A different jointing product, not another unbound bag, is the conversation if the only fault is washout.

Related pages

Kiln dried sand buying guide

Kiln dried sand

Best kiln dried sand: which bag fits your UK patio

How to apply kiln dried sand on dry UK block joints

Kiln dried sand vs polymeric sand for block joints

Sources

Public sources used for this comparison, with the amazon.co.uk listings read on 19 October 2026.

  1. CEMEX Rugby kiln dried sand datasheet (retrieved 19 October 2026)
  2. HSE INDG463: respirable crystalline silica (retrieved 19 October 2026)
  3. Tobermore: homeowner block paving guide (retrieved 19 October 2026)
  4. Pavingexpert: pointing (retrieved 19 October 2026)
  5. Paving.org.uk: how to re-sand block paving (retrieved 19 October 2026)
  6. Dansand: joint filling sand (retrieved 19 October 2026)
  7. Wickes: Dansand technical sheet (retrieved 19 October 2026)
  8. HTA: artificial grass note (retrieved 19 October 2026)
  9. Holcim: kiln dried sand datasheet, July 2025 (retrieved 19 October 2026)