Resin isn't the problem — what it sits on is
A resin bound layer is thin. It is designed to be a finish, not a structure. It can only stay flat and crack-free if the layer beneath it doesn't move. Lay it on a base that flexes, settles or was never built for the job, and the resin shows every movement as a crack.
The most common causes of cracking
- Resin laid over old tarmac or concrete that was already cracked — the old cracks reflect straight through.
- A sub-base that was too thin or poorly compacted, so it settles under the weight of cars.
- Weak or missing edge restraint, so the edges break away.
- Mixing or laying in the wrong weather, or the wrong layer thickness for the aggregate.
- Soft ground left in place instead of dug out and replaced.
Why weeds appear
A properly built resin bound surface leaves no joints for weeds to root in. Weeds usually mean seeds have blown into a surface that has started to break up, the layer is too thin or porous at the edges, or the edges haven't been sealed against soil and lawn. Moss can also form where water can't drain away through the base.
Why 'laid over your existing drive in a day' can go wrong
Laying over an existing surface can be the right route — but only when that surface has been checked and is genuinely sound, level and draining. When it is chosen because it is quicker and cheaper, the old surface's faults become the new surface's faults.
How we build to prevent it — Structure First. Surface Second.
- We assess the existing surface, base, levels and drainage on site before recommending a route.
- We only recommend an overlay where the existing base is confirmed suitable; otherwise we rebuild.
- Excavation and compacted sub-base built to suit your ground and how the drive is used.
- Firm edge restraint around the whole surface.
- A written proposal naming the construction route, what's included and what's priced separately — so if anything is ever questioned, the specification is on record.
Questions to ask any installer
- Will you excavate, or lay over what's there? Why?
- What sub-base, and how deep once compacted?
- How will the edges be restrained?
- Where will the water go?
- Who is responsible if it cracks — and is that in writing?