What the base is actually doing
Vehicle loads pass through the surface into the supporting construction and ground. Suitable support, compaction, levels and drainage help the driveway perform as intended. Problems beneath the finish can show up as movement, cracking or changes in level.
What a proper build-up involves
- Excavation to the depth the job needs — which depends on your ground and how the drive is used.
- Removal of soft or unsuitable material rather than digging around it.
- A compacted sub-base, brought up to level in layers to achieve the support required by the specification.
- Edge restraint to hold the build-up and the surface in line.
- The surface build-up itself, specified for the route chosen.
Why the depth isn't the same on every job
A drive that carries a car and a wheelie bin is not built the same as one that carries a delivery van, a caravan or a tractor. Clay and soft ground need more than firm made ground. And if there is an existing base, its depth and condition decide how much of it can be used. We set this out after measuring and inspecting, not before.
Signs that need investigation
- Localised sinking, usually where vehicles repeatedly stop or turn.
- Ruts following the line of the wheels.
- Standing water that wasn't there before.
- Cracks that keep returning in the same place after repair.
- Blocks or kerbs settling and going out of line.
What to ask for in writing before you commit
- The excavation depth you are paying for.
- The sub-base type and compacted depth.
- How edges are restrained.
- What happens if softer ground is found once excavation opens up, and how that would be priced.