Top Signs Your Paving Needs Resanding

If you've started noticing weeds pushing up between your blocks, gaps where there used to be tight joints, or water sitting on the surface after a shower of rain, these are all signs paving needs resanding — and in the North West, where we get plenty of damp weather through most of the year, those problems tend to develop faster than homeowners expect. Block paving isn't maintenance-free, and the jointing sand that holds everything together gradually gets washed out, excavated by insects, or simply breaks down over time.

The good news is that resanding is one of the more straightforward fixes in exterior maintenance — provided you catch it before the underlying structure starts to shift. This guide covers the five main signs to look out for, what's actually happening beneath the surface when each one appears, and what to do about it.

Kiln-dried sand being brushed into block paving joints after a deep clean — one of the clearest signs paving needs resanding is visible joint loss like this.

What Does Jointing Sand Actually Do?

Kiln-dried sand packed into the joints of block paving isn't just there to fill the gaps. It's doing structural work. The fine, dry particles compact together under foot and vehicle traffic to create a locking effect across the whole surface — each block is held in position by the friction of the sand against its edges. Without that, individual blocks can tilt, sink, or move independently of their neighbours.

Sand-filled joints also act as a barrier. They resist water ingress into the sub-base, reduce the number of seeds that can take hold, and limit the organic matter that accumulates and encourages moss. When the joints are healthy and full, the surface behaves as a unified, permeable structure. When they start to fail, everything that block paving is designed to resist — weeds, movement, water pooling, moss — gets a foothold.

Understanding this makes it easier to see why resanding isn't optional maintenance you can defer indefinitely. The longer depleted joints are left, the more secondary damage accumulates, and the more involved the remediation becomes.

Sign 1: Weeds and Moss Growing Between Blocks

This is usually the first thing homeowners notice. Wind-blown seeds settle into joints that have lost their sand, find a thin layer of organic debris to germinate in, and within a season or two you have visible plant growth across the surface. In shaded driveways — common in Greater Manchester terraces where one side of the street sees limited direct sun — moss can colonise the joints almost as quickly as weeds.

The problem compounds itself. Plant roots work their way down and sideways between the blocks, physically displacing whatever sand remains. Each root that grows is actively widening the joint and pushing blocks fractionally apart. Moss, meanwhile, holds moisture against the paving surface, which accelerates both biological growth and the weathering of the blocks themselves.

Pressure washing removes the visible growth, but if the joints aren't refilled afterwards, the same process simply starts again. You've reset the clock, not fixed the underlying issue. A block paving clean followed by resanding addresses both the symptom and the cause — the weeds come out, the joints are filled, and new growth has far less to work with.

Sign 2: Visible Gaps or Sunken Joints

Over years of rainfall and cleaning, the fine particles of kiln-dried sand gradually migrate downwards or wash out from the joints entirely. Eventually the depletion becomes visible to the naked eye — you can see the gap between blocks rather than a tight, filled joint, or the joint line appears dark and recessed rather than flush with the block surface. This is one of the clearest signs paving needs resanding that most homeowners will recognise.

It's also the point at which many people first go looking for a solution, because the paving starts to look tired and neglected even if the blocks themselves are in good condition. Wide, open joints make the surface look older than it is and draw the eye. If kerb appeal matters to you, this is the visual threshold worth acting on — you can read more about surface appearance and what makes a real difference in our guide to driveway kerb appeal upgrades that actually work.

Visible gaps also tell you that the structural protection the sand provides is now genuinely compromised. Rain is getting into the joints and working towards the sub-base. If your driveway was laid on a proper compacted base with adequate drainage, it may tolerate this for a while. If the base is borderline, water ingress accelerates deterioration significantly.

Sign 3: Blocks Rocking, Shifting or Sounding Hollow

If individual blocks move when you stand on them, rock underfoot, or produce a hollow sound when walked across, the joint sand has depleted to the point where the locking mechanism has effectively failed. Blocks are no longer behaving as part of a unified surface — they're moving independently, which causes uneven wear, exposes edges to chipping, and creates a trip hazard.

This is where what starts as a cosmetic issue becomes a structural and safety concern. On a driveway with vehicle traffic, loose blocks are subject to forces that compact sub-base materials unevenly, accelerating localised sinking. On a patio, rocking slabs are a genuine slip and trip risk, particularly when wet — a problem that's worth understanding in more depth if you've also noticed the surface becoming slippery, which we cover in the related guide on why your driveway is so slippery.

At this stage, resanding alone may not be sufficient. If blocks have shifted significantly, they may need to be lifted, the bed beneath relevelled, and then relaid before resanding. A professional assessment is worth having before you invest in remediation that might not fully address the problem.

Sign 4: Ants and Insects Nesting in the Joints

This one catches people off guard. Ant activity is one of the signs paving needs resanding that doesn't look like a paving problem at first — it looks like a pest problem. But what's actually happening is that ants are excavating the remaining sand from the joints to build their nests, depositing fine granules on the surface in small piles around the nest entrances. A single colony can remove a significant volume of sand from a localised area over the course of a summer.

Because ants nest in patches, joint depletion from insect activity tends to appear unevenly across the surface — a cluster of blocks with visible gaps surrounded by paving that still looks fine. If you're seeing those characteristic fine sand deposits on the surface and small holes in the joints, that's the mechanism. Treating the ant infestation and resanding go together; there's little point refilling joints that are still actively being excavated.

Sign 5: Surface Flooding or Poor Drainage After Rain

Block paving is designed to be permeable — water passes through the joints and into the sub-base rather than running off in sheets. When joints are depleted or clogged with organic debris, that permeability is lost. Water sits on the surface, pools in low spots, or runs towards the property rather than dispersing evenly. In Greater Manchester, where rainfall is a regular feature of most months, this isn't a theoretical problem.

Pooling water near the house is worth taking seriously. Repeated saturation close to a building's edge affects pointing, can contribute to damp in older properties, and in winter creates ice patches that are a genuine hazard. Resanding restores proper drainage by opening the joints back up and allowing water to move through the surface as intended.

It's worth noting that if drainage was poor from the original installation — wrong fall, inadequate sub-base, poor edge restraints — resanding won't fully resolve the problem. But if the paving was laid correctly and drainage has deteriorated over time, resanding is often the fix. A driveway clean beforehand also removes the debris blocking joints and allows you to properly assess what's happening beneath.

When Should You Call a Professional for Resanding?

The most important thing to understand about resanding is the order of operations. Sand brushed into dirty, weed-filled, or damp joints won't compact properly and won't last. The correct sequence is always: pressure wash the surface, allow it to dry fully, then apply kiln-dried sand and compact it in. Skipping the clean is the single most common reason DIY resanding fails within a season. If you're also dealing with block paving that's visibly discoloured or heavily soiled, the block paving re-sanding service should follow, not replace, a proper clean.

Sand type matters too. Kiln-dried sand is the correct product — it's processed to a fine, consistent grade and low moisture content that allows it to flow freely into joints and compact under traffic. Building sand or sharp sand hold moisture, break down faster, and encourage the moss and weed growth you're trying to prevent. Any professional using the wrong grade of sand is wasting your money.

C&C Precision Precision Pressure Washing carries out combined clean-and-resand jobs across Greater Manchester, including areas like Oldham, Rochdale, Bury and Stockport, working to the correct process on each visit. Pricing for block paving work runs from around £3.50/m² for a clean, £4.25/m² with chemical treatment, £5.50/m² for a full restoration with resanding, or £2.00/m² for resanding only where cleaning has already been completed. If you're weighing up whether to seal afterwards — which does meaningfully extend how long the sand lasts — the guide on block paving sealing and whether it's worth it covers that honestly.

Quick Checklist: Is Your Paving Due a Resand?

Run through these five points and be honest about what you're seeing on your own paving. Each one on its own is a sign paving needs resanding; more than one appearing together suggests the joints are significantly depleted and remediation shouldn't be left much longer.

• Weeds or moss growing between blocks — organic matter has replaced the sand in the joints and seeds are germinating.
• Visible gaps or sunken joint lines — sand has washed or settled out to the point where the depletion is visually obvious.
• Blocks rocking, shifting or sounding hollow underfoot — the locking effect has failed; this is a structural issue, not just cosmetic.
• Fine sand deposits and ant holes on the surface — insect activity is actively removing what joint sand remains.
• Water pooling on the surface after rain — permeability has been lost; drainage is no longer working as designed.

On a well-maintained domestic driveway in the North West, resanding is typically needed every two to five years. Driveways with heavier vehicle traffic, overhanging trees dropping leaf debris, or shaded aspects that stay damp for longer will be at the shorter end of that range. Sealing after resanding pushes the interval out considerably. If you're not sure where your paving sits, send a few photos — it takes about two minutes to get a read on what's needed.

Frequently asked questions

Can I just pour sand into the joints myself without pressure washing first?

You can, but it's largely a waste of time and money. Dry sand brushed into dirty, weed-filled joints won't compact or lock properly, and any organic matter left behind will push new growth straight back through. The right order is always clean first, let it dry, then resand with kiln-dried sand.

What type of sand is used for block paving resanding?

Kiln-dried sand is the correct product — it's fine, dry and flows easily into joints, compacting firmly when vibrated or trafficked. Building sand or sharp sand are the wrong grades and will hold moisture, encouraging moss and causing joint failure faster. Any professional should be using kiln-dried as standard.

How long does resanding last before it needs doing again?

On a well-maintained driveway with regular cleaning, kiln-dried sand typically lasts two to five years in Greater Manchester's climate. Driveways with heavy vehicle traffic, overhanging trees, or poor drainage at the edges will lose sand faster. Sealing after resanding can significantly extend the lifespan of the joints.

Does block paving need to be sealed after resanding?

Sealing isn't essential but it's a smart upgrade when done at the same time as resanding. A quality block paving sealer locks the sand in place, inhibits weed and moss growth, and makes future cleaning much easier. It also enhances the colour of the paving, which is a bonus if kerb appeal matters to you.