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Cordless weeder for block paving

Updated: 21.10.2026

The joints on a concrete block drive are green again, and a round patio brush looks as if it should drop straight in. A cordless weeder for block paving usually cannot. The gap is a few millimetres wide and the disc is wider, so the bristles clear the mouth, pull jointing sand, and leave the root. The [cordless joint cleaner comparison](/hub/garden-tools/cordless-joint-cleaner) is the eight amazon.co.uk listings if you still need a tool. Products Compared used those files and public UK sources, not a lab test. A qualifying purchase can earn a commission at no extra cost to you.

The joints on a concrete block drive are green again, and a round patio brush looks as if it should drop straight in. A cordless weeder for block paving usually cannot.

Our top picks

Einhell Einhell GE-CC 18 Li kit

Best overall

Einhell Einhell GE-CC 18 Li kit
9.0/10about £83.65
View offer
Parkside Parkside 20 V patio cleaner

Alternative

Parkside Parkside 20 V patio cleaner
8.4/10about £108.99
View offer
Einhell Einhell GC-CC 18 Li solo

Best value

Einhell Einhell GC-CC 18 Li solo
8.2/10about £47.36
View offer
On this page
  1. 1.How wide the joint is
  2. 2.Knife and brush together
  3. 3.Put the sand back
  4. 4.What the listings can and cannot do

How wide the joint is

The Weed Guy puts block-paving joints at about 2–5 mm, often about 3 mm, and cites a 5 mm maximum in BS 7533-3. Pavingexpert’s detailing page cites the same 5 mm maximum. The brush is the mismatch. The Weed Guy puts powered heads at about 8–15 mm thick. Einhell’s own notes aim the brushes at crevices of about 10–15 mm, and the cutting widths in this set are about 100 mm on Einhell and Sealey and 110 mm on Parkside. Six millimetres of nylon still does not enter a 3 mm joint.

Knife and brush together

Use both tools, for different depths. The Royal Horticultural Society starts hard-surface weeds with a knife for the root and a wire paving brush for seedlings and moss. On block paving the knife is the part that reaches 3 mm down the joint. Run it along the gap, lift the root, and do not lever the block up. The cordless head then speeds the moss across a long drive. It is a poor substitute for the knife on an established root. Work in that order on a dry afternoon. Knife the roots you can see. Steel is faster on plain concrete blocks and it will still mark a soft face, which the wire brush or nylon patio cleaner page covers. Einhell kit reviewers were surprised how much sand and soil the pass threw out. You will put kiln-dried sand back, not this spoil. A pressure washer strips the joint and does not kill the root, which is Homebuilding’s warning.
Einhell Einhell GE-CC 18 Li kit

Testsieger

Einhell Einhell GE-CC 18 Li kit
9.0/10about £83.65
View offer

Put the sand back

Empty joints are why a brushed drive starts to move. Pavingexpert ties lost sand to lost interlock: the blocks rely on that fill, with the edge restraint, to stay put. Marshalls says put kiln-dried sand back after the growth is gone. Do it the same day, once the surface is dry. Brush kiln-dried sand diagonally across the joints so it falls in, then sweep the excess off. Ordinary building sand is the wrong bag. It is often damp and it does not flow into a 3 mm joint the way kiln-dried sand does. If blocks rock after you have refilled, stop. That is a paving contractor.

What the listings can and cannot do

Several listings in this set name block paving, and the reviews qualify the claim. Sealey’s bullets name it, and that file has no customer reviews. Einhell and Ryobi reviews say the head is too wide and it throws sand. None of these tools enters the gap. They are mouth cleaners with a battery. Keep a knife and a bag of kiln-dried sand beside the shaft.

Common questions

Can a 100 mm brush enter a 3 mm joint?
No. The cutting width is the diameter across the face. The thickness that would have to enter the gap is still about 6–15 mm on the figures these sources use, against a joint of about 2–5 mm. Einhell aims the brushes at crevices of about 10–15 mm. The disc cleans the mouth and spins on the weed. Reviews on the Einhell and Ryobi files describe that miss. A knife is what goes down the 3 mm line.
Do I still need a weeding knife?
Yes, if the root is the problem. The Royal Horticultural Society uses a knife for roots and a brush for seedlings and moss. The cordless head shortens the moss work on a long drive and does not replace the knife in a narrow block joint. Einhell reviews call the tool weak once weeds are established. Do the knife first, then the brush, on a dry day.
Will the blocks loosen if I leave the joints empty?
They can. Pavingexpert links empty joints to lost interlock, which is how the blocks stay locked with the edge restraint. Sand pulled out with the weeds has to go back. If the blocks already rock, or the edge has moved, refill is not enough. That drive needs a paving contractor, not another pass with the brush.
Kiln-dried sand or ordinary building sand?
Kiln-dried sand. It is dry enough to brush into a narrow joint. Building sand is often damp, so it clumps and stays on the face. Pave Direct and Pavingexpert both describe brushing kiln-dried sand on a dry surface and sweeping the excess off. Do not put the moss and soil you just lifted back into the gap.
Does the surface have to be dry?
Yes for the sand, and it helps the brush. Wet soil clogs the head, which is the review pattern on these tools. Kiln-dried sand on a wet drive does not flow into the joint. Wait until the blocks are dry, then sand the same day. Do not hose a battery tool the listing does not rate for water. A pressure washer is worse for the same joints: Homebuilding says it strips the fill and leaves the root.
Which listing in this set even claims block paving?
The Lazy-Weeder title, the Sealey bullets, and the NETTA title name it. Einhell and Ryobi show it mainly in reviews, which say the head is too wide or wanders. Sealey has no review line in this file, so the bullet is not buyer evidence. NETTA’s 3.7 from 180 reviews includes weak results on tough grass. A title that says block paving does not mean the disc fits a 3 mm joint.

Related pages

How to use a cordless patio cleaner

Cordless patio cleaner buying guide

Cordless joint cleaner

Best cordless patio cleaner for the battery you own

Wire brush or nylon brush: which patio head to fit

Sources

Public UK sources used for this comparison. Listing prices, stars and review counts are the amazon.co.uk figures saved for this set on 19 October 2026.

  1. Einhell UK, GC-CC 18 Li-Solo (retrieved 19 October 2026)
  2. Ryobi UK, RY18PCA-0 (retrieved 19 October 2026)
  3. The Weed Guy, weeding block paving and patios (retrieved 19 October 2026)
  4. Marshalls, how to clean block paving (retrieved 19 October 2026)
  5. Pavingexpert, refurbishment and joints (retrieved 19 October 2026)
  6. RHS, weeds on hard surfaces (retrieved 19 October 2026)
  7. HSE, garden pesticides (retrieved 19 October 2026)
  8. HSE, using the right type of PPE (retrieved 19 October 2026)
  9. GOV.UK, Supply of Machinery (Safety) Regulations 2008 (retrieved 19 October 2026)