What is the difference between the two fixes?
Re-sanding means cleaning out debris and weeds from the joints, brushing in dry jointing sand and compacting so the blocks lock together again. Nothing is lifted. Relaying on a corrected base means taking the blocks up, digging out and rebuilding whatever layer has failed, laying fresh bedding, putting the blocks back and then jointing and compacting.
The first is maintenance; the second is a repair. Both have their place, and choosing the wrong one wastes money either way. Re-sanding a dip that has sunk because of a weak base changes nothing that matters, while relaying an area that only needed joint sand disrupts paving that was otherwise sound.
How can you tell which one your paving needs?
The simplest test is a straight edge or a long spirit level laid across the problem area in several directions. If it sits flat and the issue is that blocks move, rattle or have weeds in the joints, re-sanding may well be enough. If there is a visible gap under the straight edge, the surface has dropped and the support beneath needs attention.
| What you see | Re-sanding likely enough | Relay on corrected base likely needed |
|---|---|---|
| Surface level, joints empty | Yes | No |
| Blocks rattle but stay level | Usually | Only if bedding has shifted |
| Clear dip under a straight edge | No | Yes |
| Ruts along wheel lines | No | Yes |
| Weeds in joints only | Yes | No |
| Blocks spreading at an edge | No, edge must be fixed | Often, with edge reset |
When is re-sanding the right answer?
Re-sanding suits paving whose base is doing its job but whose joints have been emptied by pressure washing, heavy rain flowing across the surface, or years of sweeping. The blocks may feel slightly loose or click underfoot, and weeds may have taken hold, but the surface is still level and water still runs off.
- remove weeds and organic debris from the joints
- let the surface dry fully so sand can run down
- brush in dry jointing sand until the joints are full
- compact with a protected plate where appropriate
- top up the joints again and sweep off the surplus
For loose blocks with empty joints, our loose pavers service often starts with exactly this, and checks whether any individual blocks need relaying. If the straight edge test shows a dip as well, the plan changes to a relay of that area, while the rest can still be re-sanded.
When does only a relay on a corrected base work?
When the surface has sunk, the problem is under the blocks, not between them. Adding joint sand to a dip simply gives you a well-jointed dip. The bedding may have washed out, the sub-base may be thin or poorly compacted, or an old trench may have settled. Each of these requires the blocks to come up.
A lift and relay repair removes the failed layers, rebuilds them and puts the same blocks back. The joints are then filled as part of the job, so a relay always includes the re-sanding as its final stage. Our guide to base failures describes the most common faults found once the blocks are up.
Can re-sanding hide a deeper problem?
It can, and this is worth knowing before you hire anyone. A freshly sanded surface looks tidy, so a dip can seem less obvious immediately afterwards. But if the base is failing, the joints will empty again faster than before and the dip will keep growing. Rapid loss of joint sand is itself a warning sign.
If you have re-sanded and the joints are open again within a season, or a dip is still visible under a straight edge, the cause is likely underneath. At that point a subsidence diagnosis is more useful than another bag of sand.
What about polymeric or bound jointing materials?
Some owners ask about jointing products that harden after wetting, intended to resist weeds and washout. They can have a place on stable, well-laid paving. They do not correct a sunken base, and if the base later moves, a hardened joint may crack or make the blocks harder to lift for a repair. We work with Mapei products. We do not make claims about specific jointing products here; if you are considering a bound joint, it is worth discussing whether the paving is stable enough for it before going ahead.
Why do joints empty in the first place?
Knowing why the sand left helps decide which fix you need. Pressure washing at close range is the most common avoidable reason. Water running across the paving in a stream, for example from a downpipe or a higher garden, scours joints along its path. Sweeping with a hard brush along rather than across the joints can also pull sand out.
Those causes leave the base intact, so re-sanding and changing the habit or the water route is enough. But sand can also vanish downwards, into a bedding layer or sub-base that is itself moving or washing out. In that case the joints empty from below, the surface starts to dip, and the right fix is a relay.
What does each option mean for disruption?
Re-sanding causes very little disruption. The surface stays in place, the area can normally be walked on again once the sand has been brushed in and the surplus swept away, and the work needs no excavation or waste removal. It is the kind of job that can be fitted around a let or a busy household.
Relaying is more involved: the area is fenced off, blocks are stacked nearby, material is brought in and waste taken away. For owners abroad, we schedule it for a time the property is empty where possible and send photos so the work can be followed remotely. Choosing the right option keeps disruption in proportion to the problem.
Is a combination of both ever the right plan?
Very often. A typical driveway may have one area that has sunk near the garage and a wider area where the joints have simply emptied. Relaying the sunken part on a corrected base and re-sanding the rest gives a consistent finish without lifting paving that does not need it.
This is the approach we usually suggest when the evidence supports it. Photos of the whole surface, with a straight edge in the worst areas, let us propose a plan zone by zone. Send us a photo and the approximate m² – free, no-obligation quote. Our article on what can go wrong when relaying pavers explains how to judge the relay part of the work.
Frequently asked questions
Will refilling the joints fix sunken pavers?
No. Joint sand locks blocks together but cannot raise them. If the surface has dropped, the support under the blocks has failed and the area must be lifted, the base corrected and the blocks relaid. Re-sanding is the last step of that repair, not a substitute.
How do I check whether my paving has sunk or just has empty joints?
Lay a straight edge or long spirit level across the area in several directions. A visible gap underneath means the surface has dropped. If it sits flat and the blocks only move or rattle, empty joints are the more likely issue.
Why do my blocks click when I walk on them?
Clicking usually means the joints have lost sand and the blocks touch each other loosely, or the bedding under one block is uneven. Re-sanding and compacting often solves it. If one block keeps clicking afterwards, its bed needs correcting.
How often does block paving need re-sanding?
There is no fixed interval. It depends on cleaning methods, water flow and use. Check the joints from time to time and top up when they look low. Pressure washing almost always means re-sanding afterwards.
Can I re-sand the paving myself?
Yes, on stable, level paving. Clean out the joints, let the surface dry fully, brush in dry jointing sand, and top up again after a few uses or rain. If the surface has dipped, re-sanding alone will not help and the area should be assessed.
Do hardening joint products stop sinking?
No. They may resist weeds and washout on stable paving, but they do not correct a weak base. If the base moves later, hardened joints can crack and make the blocks harder to lift. Fix any sinking first.
Does a relay always include new joint sand?
Yes. After the blocks are relaid on corrected bedding, joints are filled with dry sand before and after compaction. A relay therefore includes re-sanding of the repaired area as standard.
Can you relay one part and only re-sand the rest?
Yes, and it is often the most sensible plan. Sunken areas are relaid on a corrected base, while sound areas with empty joints are cleaned and re-sanded. The quote describes each zone so you can see what is done where.
Why does my joint sand keep disappearing?
Common reasons are water running across the surface in a stream, close-range pressure washing, or a base that is still moving. If sand vanishes repeatedly from the same area, check for a dip or a water source and send photos.
Is re-sanding worth doing before a sale?
If the paving is level, re-sanding and weeding make it look cared for and lock loose blocks. If there are dips, buyers will still notice them, and a proper repair of those areas is a better investment.