In short: resin bound itself rarely cracks on a stable base. Straight cracks usually follow joints or cracks in old concrete or tarmac beneath; irregular cracking with sinking usually means the sub-base has failed. Prevent cracks by treating base defects before overlaying, or by building a properly compacted new base.
Reading a crack
| What you see | Most likely cause |
|---|---|
| Straight line, regular spacing | Expansion or construction joints in concrete beneath |
| Follows an old patch or edge | Crack or joint in the old tarmac or concrete |
| Spider-web cracking with dips | Sub-base failure or soft ground |
| Crumbling at the edges | Missing or weak edge restraint |
| Fine crazing over the whole surface | Thin resin layer or poor mix |
Prevention
- Treat or break out cracks and joints before overlaying concrete.
- Never overlay block paving, which moves at every joint.
- On rebuilds, use an adequate, well-compacted sub-base and a geotextile.
- Fit firm edge restraint all round.
- Lay to the system's specified depth.
Repair
Isolated cracks can often be cut out and relaid, ideally after the cause below is fixed. See repairs.
Frequently asked questions
Is a hairline crack a sign of failure?
Not necessarily. A fine crack over an old base joint may be cosmetic. Watch whether it widens, spreads or the surface either side moves, and report it to the installer if the drive is under guarantee.
Does clay soil cause cracking?
Clay shrinks and swells with moisture, which can move a shallow or poorly built base. Parts of north Guildford and the area towards Woking include London Clay, so base depth and compaction matter. The installer should assess ground conditions on site.
Related guides
Repairs and restoration
Loose stones, cracking, fading and ponding: what causes each and how they are put right.
Resin over concrete
When an existing concrete drive is a good base, and the cracks, joints and drainage issues to check.
How long resin driveways last
Typical lifespan, the four things that shorten it, and how to protect yours.