Loose Block Paving? We'll Re-Sand, Re-Level and Stop the Rocking in Knowle

Block paving earns its keep by being repairable: unlike a cracked concrete slab, individual blocks can be lifted, re-levelled and relaid. But loose blocks are also the system asking for attention, and ignoring them is how a small patch of wobble becomes a driveway-wide problem. This page explains why blocks loosen, how we diagnose the cause, and what a proper repair involves.

Why block paving comes loose

Most loose blocks trace back to one of four causes. Lost jointing sand is the most common — the kiln-dried sand brushed between the blocks is what locks them together and spreads wheel loads; wind, rain, jet washing and ants carry it away, and once it is gone the blocks start to move. Poor or failed edge restraints are the next: block paving is a flexible surface, and without a solid edge course held by concrete haunching or a firm kerb, the blocks at the boundary creep outwards and the loosening works inwards from there. Bedding problems — sand laid too thin, too thick or over an uncompacted base — show up as areas that sink and rock under wheel paths. And water is the multiplier: it washes bedding sand out through any gap and softens the ground below, so a poorly drained drive loses blocks far faster than a well-drained one.

How we diagnose it

We walk the drive and map where blocks rock, sink or have spread, then look for the cause of each pattern. Widespread fine movement usually means jointing sand loss; a loose band along the boundary points at edge restraints; dips in the wheel paths or around parked cars suggest bedding or subbase issues; and areas that worsen after heavy rain tell us water is washing through. We lift a block or two in the worst area — that is the beauty of the system — to see the condition of the bedding sand and base directly, and we check the falls to see where water goes.

The repair

The right repair depends on the diagnosis, and here is what each looks like. Re-sanding is quick: clean the joints and brush in fresh kiln-dried sand to lock the surface back together, ideally re-doing it after a season as it settles. Where edge restraints have failed, we rebuild them — a solid edge course set in concrete or a proper kerb — because re-laying blocks against a rotten edge simply restarts the creep. Where blocks have sunk or rocked badly, we lift them, remove the disturbed bedding, re-level and compact the base, lay fresh bedding sand and relay the blocks, then re-sand the joints. Where our probing shows the subbase itself has failed, we will say so: those sections need the base rebuilt, not just the blocks rearranged. And where the drive lacks fall and feeds water into the joints, we will discuss correcting the drainage, because no amount of re-sanding survives a drive that sheds water into its own bedding.

Honest limits

Block paving repairs last well when the cause is fixed, but we do not guarantee that sand will not need topping up again — it is a consumable, particularly on exposed drives and after jet washing — nor that an ageing drive with poor original compaction will stay perfectly level. What we do is fix the structural causes, relay properly, and tell you how to maintain the surface so the repair earns its keep. New paving and larger relays are quoted projects: the visit assessment tells us the scope, and the price follows a survey rather than a guess.

Between visits

Keep the joints topped up with kiln-dried sand — a brush-in every year or two is cheap insurance. If you jet wash the drive, re-sand immediately afterwards, because jetting strips the joints clean. Pull weeds when they are small; roots widen joints and hold water. And get rocking blocks looked at promptly — the movement spreads block by block and each year of traffic makes the underlying bedding worse.

Booking

You pay a booking fee when you book, and labour is charged hourly at a rate that depends on how soon you need the visit. The full cost of the repair is quoted and approved before we start, with materials such as sand, blocks and concrete for haunching quoted separately. When you book, tell us the approximate area affected, whether blocks rock only underfoot or under cars too, and whether it worsens after rain — that helps us bring the right materials.