How to Clear Weeds and Moss From Block Paving With a Strimmer
By Laura Pemberton · Updated on 11 October 2026
Short answer: swap the nylon line for a steel wire brush head on a petrol, straight-shaft strimmer, work it along the joints rather than across the faces of the blocks, then sweep up and refill the joints with kiln-dried sand. Nylon line works, but on paving it disappears fast; a wire head scrubs out weeds, moss and algae without any weedkiller. It isn't for electric or cordless strimmers, and it needs proper protective kit.
Why does strimmer line wear out so fast on paving?
Line is made to cut grass, not to be dragged over concrete and stone. On block paving it frays and snaps on the edges of the blocks. "Before I started, I wound on 8 metres of heavy duty line and I used it all up in about 20 minutes!" (Gardeners Corner forum) [UK]. On Arbtalk, a UK tree care forum, one member wrote: "I have to strim weeds on block paving and do with a normal line. You get through line quickly and the heads wear as well." [UK]
Some gardeners still prefer line, with a powerful machine and heavy square line, for its control. For a whole drive with moss and weeds in every joint, many switch to a wire head.
What is a wire brush strimmer head?
It is a round head of twisted steel wire that replaces the line head. As it spins, the wires scrub into the joints and pull out moss, weeds and algae, along with the dirt they grow in. It is a cleaning tool for hard surfaces: block paving, brick pavers, slabs, patios, drives and kerb edges.
"if you want rid of moss, weeds and algae so that your brick pavers look immaculate, then this is the tool." (Amazon UK) [UK]
Will a wire head fit your strimmer?
This is the most common reason people are disappointed: "Doesnt fit strimmer" is a typical one-line review [UK]. Wire heads are for:
- Petrol strimmers (brushcutters) of around 25cc and up
- Straight-shaft machines
They are not suited to electric or cordless strimmers, or to curved shafts, which don't have the power for a steel head. Check the fixing too: good heads come with adapters for the common brands.
The HSE has warned that "Non-standard metal brush cutting accessories fitted to petrol driven brush cutters can fail catastrophically in-service", and that "Manufacturers' advice should be followed as to the appropriate combinations of cutting tools and guards." So check your strimmer's manual for the heads and guard it accepts before you fit one.
What protective kit do you need?
A wire head throws debris, and now and then a wire. "Be aware of the odd wire pinging off at high speed amongst the debris and be advised to wear substantial boots" (Amazon UK) [UK]. The RHS advises: "Wearing safety glasses or a face shield when using a hedge trimmer or strimmer is strongly advised."
- A face visor or safety glasses
- Ear defenders
- Long, thick trousers and sturdy boots
- Gloves with a good grip
- Nobody, pets included, within range while you work
How do you clear block paving with a wire brush head, step by step?
- Pick a dry day.
- Clear the area. Move pots, bikes and anything that could be hit, and pick up loose stones, which "become missiles if the strimmer hits them" (Amazon UK) [UK]. Expect the odd spark when the wires touch stone, so keep your fuel can well away.
- Fit the head and guard following the instructions, and check that the head is tight.
- Start the strimmer and let it reach working speed before the head touches the ground.
- Work along the joints with the head almost flat, in light, steady passes. Let the wires do the work: pressing hard only wears the head faster and makes the machine buck.
- Ease in near walls and kerbs to avoid kickback: "if I make contact with my stone border or wall it will give a decent 'kickback'" (Amazon UK) [UK].
- Sweep up all the debris, and look for any loose wire so it doesn't end up in a pet's paw.
- Refill the joints (next section).
Why should you re-sand the joints afterwards?
Scrubbing the joints takes some of the jointing sand out with the weeds, and that sand does a job. Pavingexpert explains that "jointing sand is not there simply to fill the gaps between adjacent blocks": "it provides the essential friction which then generates the horizontal and vertical interlock." Bradstone's advice: "Always use kiln-dried sand", fill the joints in dry weather, and remember that "Properly filled joints deter weed seeds from settling and germinating."
- Wait for a dry day and a dry surface.
- Spread kiln-dried sand over the paving.
- Brush it diagonally across the joints until they are full.
- Sweep off the excess.
What are the alternatives?
| Method | Good for | Limits |
|---|---|---|
| Weeding knife and wire hand brush | A small patio or a few weeds; the RHS suggests "a paving brush with angled wire bristles" | Slow on a whole drive, hard on knees and back |
| Strimmer with nylon line | Quick top growth | Eats line on paving |
| Wire brush strimmer head | Whole drives and patios: moss, weeds and algae in the joints | Petrol, straight-shaft machines only; protective kit; re-sand afterwards |
| Pressure washer | Dirt and algae on the surface | Also blasts sand out of the joints |
| Weedkiller | Little effort | "The RHS does not support the use of weedkillers and recommends that alternative control methods are used." Many owners avoid it for pets: "I can't use weedkiller because of my dog, these work great" (Amazon UK) [UK] |
To clean the surface afterwards without a pressure washer, see Hose Nozzle vs Pressure Washer. For weeds in the lawn rather than the paving, see how to pull weeds without kneeling.
How long does a wire head last?
It depends on the surface. On block paving, a good head lasts around a season of normal use; on grass and softer weeds, longer. Cheap copies can wear out far faster: "Wore it out in just 1 tank of fuel." (Amazon UK) [UK]
What about the ST60 PRO?
It is our wire brush strimmer head. The facts:
- A twisted carbon steel wire head that replaces your line head, 15 cm wide
- For petrol, straight-shaft strimmers of around 25cc and up; not for electric, cordless or curved-shaft machines
- A universal adapter kit (Stihl, Ryobi, Husqvarna, Echo and more), a spanner and an illustrated guide in the box
- Clears moss, weeds and algae without chemicals
- A season of normal use on block paving
- A free pair of anti-cut gloves, our Lifetime Warranty and a 90-day money-back guarantee
Its limits, honestly: it needs a petrol, straight-shaft machine and the protective kit above, it isn't made for neat lawn edging, and you will need to re-sand the joints afterwards. Find it on the ST60 PRO page.
FAQ
Can I use a wire brush head on an electric strimmer?
No. Wire heads need a petrol, straight-shaft strimmer of around 25cc and up.
Will a wire brush head damage block paving?
Worked lightly along the joints, it is made to clean them. One UK reviewer, after two or three weekends with a wire head, reported "no apparent scratches/damages to the surface" [UK]. Keep the head flat, don't dig into the faces of the blocks, and try a small patch first on natural stone.
Is it better than weedkiller?
It leaves no chemicals behind, so the patio is ready to use straight away, with no wait before pets and children can go on it.
Does it stop weeds coming back?
It removes them; refilling the joints with kiln-dried sand slows the regrowth. Weeds will come back in time, so plan to repeat it.
When is the best time to do it?
Many people do it in spring and again before winter. As the RHS points out, "Weeds can make paths and driveways slippery and uneven, increasing the risk of trips and falls."
About the author: Laura Pemberton writes the product copy and blog articles at Vauscher. She also works on product research, helping select the home, garden and DIY products in our range.