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Does jointing sand stop weeds?

Updated: 21 October 2026

You bought the bag because the drive joints are green, and the sack says No Grow, or the bullets promise a hard finish. Joint sand can make a poor seedbed, or a harder joint that is more awkward to colonise. It does not kill a root that is already there, and seed sitting in surface dirt can still grow. That is the limit behind the question does jointing sand stop weeds. Prices and the seven listings are on the [joint sand comparison](/hub/flooring-tools-and-accessories/joint-sand). Which type of bag you are holding is on the [buying guide](/hub/flooring-tools-and-accessories/joint-sand/sub/joint-sand-buying-guide). This page does not give a herbicide dose. A purchase through our links can earn a commission at no extra cost to you.

You bought the bag because the drive joints are green, and the sack says No Grow, or the bullets promise a hard finish. Joint sand can make a poor seedbed, or a harder joint that is more awkward to colonise.

Our top picks

Sika Sika setting sand, buff, 20 kg

Best overall

Sika Sika setting sand, buff, 20 kg
8.4/10about £21.99
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Laeto Laeto kiln dried sand, 20 kg

Best value

Laeto Laeto kiln dried sand, 20 kg
8.2/10about £16.14
View offer
Dansand Dansand No Grow kiln dried, 20 kg

Alternative

Dansand Dansand No Grow kiln dried, 20 kg
7.8/10about £20.39
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On this page
  1. 1.Where the weed is actually growing
  2. 2.What Dansand says it does
  3. 3.What the reviews in this set show
  4. 4.What to do instead of expecting a permanent stop

Where the weed is actually growing

The plant you can see is often seed in dust, moss and old sand at the top of the joint, not a root from under the drive. The Weed Guy’s paving note says debris in the joint is the seedbed, and kiln-dried sand on its own barely changes it. Pulling the leaf leaves the root. Brushing new sand over that root leaves the plant with a fresh collar of sand. Path and Patio’s jointing guide puts weed-resistant as less maintenance, while surface dirt can still germinate seed. Nobody in this comparison has a trial that shows a permanent stop.

What Dansand says it does

Dansand No Grow is kiln-dried joint sand with a mineral additive. The product sheet and the UK shop describe a high pH, and a later paragraph puts that around 10.4. Use the high-pH line, not an older low-pH sentence. The idea is a poor place for new weeds, not a spray that kills what is already growing. Wickes’ sheet for the 20 kg bag says Dansand is not a weed killer. Clean to about 40 mm, take existing weeds out, keep to about 1–5 mm joints, and use a free-draining unbound base. Roots are not eradicated. A Trustpilot reply from Dansand restates that limit. It is not proof the sand works. Mix the bag, then brush it into dry joints. The sequence is on how to brush sand into block paving.
Sika Sika setting sand, buff, 20 kg

Testsieger

Sika Sika setting sand, buff, 20 kg
8.4/10about £21.99
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What the reviews in this set show

The captured reviews do not support a permanent stop. On the 20 kg No Grow listing, notes include weeds within a week and sand that washed out. On the 10 kg bag, a review says most of it washed away after a few days of rain, so there was no full joint to judge. Easy Fix, 3.8 from 471 reviews, is dominated by weed complaints. A 2015 review says new sand does not deal with weeds already rooted. The polymeric bag’s reviews split on whether it set. A joint that emptied at six weeks is not a weed barrier you can time. Sika, 4.2 from 2,591 reviews, still has weeds in the notes, including growth on top of a joint that had set. A 5 to 10 years line from another site is not a life measured on these ASINs.

What to do instead of expecting a permanent stop

Take the roots out to the depth the product asks for. For Dansand that is about 40 mm of clean joint. For Sika it is at least 25 mm, with no pre-fill, and only on joints of 2–5 mm. Then keep the joint full. A mineral sand that washes out cannot inhibit anything. Do not read No Grow, or resists weeds and insects on the Sika bullets, as a guarantee. If the blocks rock or the edge has failed, that is a paving repair. The loose-or-curing condition is on kiln dried sand vs setting sand. Buy the inhibitor only after the joint is empty, dry and deep enough, and expect to weed the surface again.

Common questions

Does kiln-dried sand stop weeds?
Not in any way you can rely on. Loose kiln-dried sand fills the joint and locks blocks by friction. When it washes out, the gap collects dust and seed. Laeto’s bullets mention weeds for years. Reviewers say the sand does not set, and a full loose joint is still a place for seed. Treat it as a filler you top up, not as a weed control.
Does Dansand No Grow kill weeds I can already see?
No. Wickes’ sheet says Dansand is not a weed killer, and the product sheet says the same limit in different words: existing roots are not eradicated. You remove the weeds, clean to about 40 mm, and then brush the sand in. The high-pH additive is meant to make the joint a poor seedbed afterwards. It does not replace pulling the plant that is already there.
Why are weeds back a fortnight later?
Usually because the root was left in, the joint was only topped, or the sand washed out before it could matter. Reviews on the 20 kg No Grow bag include weeds within a week. Easy Fix reviews say the same pattern over a much longer file. Seed in surface dirt can also germinate on top of a joint that was filled correctly. A fortnight is not a defective bag by itself.
Does a hard-setting sand stop weeds for good?
No. Sika reviews include weeds on top of a joint that had set. A hard joint can slow some growth and still collect dust that grows a weed. The polymeric bag’s reviews do not even agree that it set. Nothing in this comparison is a permanent stop, and a 5 to 10 years line from another site is not a result for these listings.
What about moss and algae?
Dansand treats moss and algae as a different problem from weeds in the joint. A mineral sand does not clean a green film off the block face. You still have to remove that growth and keep debris off the surface. Shade and damp will bring it back on the blocks even when the joint itself is full. The bag is not a patio wash.
Should I put the mineral sand against the house wall?
No. Dansand says not to use the mineral joint sand against a house plinth, because of salts. Use a neutral sand on that strip and keep the No Grow sand to the open paving joints. The rest of the drive can still take the inhibitor sand if the joints are the right width and depth and you have removed the roots first.

Related pages

Best joint sand

Joint sand

Kiln dried sand for block paving: measure, then bag

How to brush sand into block paving, dry then cure

Kiln dried sand vs setting sand: stay loose or cure

Sources

Public UK sources and amazon.co.uk listings, checked on 19 October 2026. Shelf prices and star lines are the figures in the display file.

  1. Pavingexpert dry sand jointing (retrieved 19 October 2026)
  2. Pavingexpert loose fill (retrieved 19 October 2026)
  3. Interpave concrete block paving (retrieved 19 October 2026)
  4. Tobermore block paving installation guide (retrieved 19 October 2026)
  5. Holcim UK kiln-dried sand sheet, July 2025 (retrieved 19 October 2026)
  6. Sika UK setting sand how-to (retrieved 19 October 2026)
  7. HSE indg463 silica dust (retrieved 19 October 2026)
  8. Dansand joint filling sand product sheet (retrieved 19 October 2026)