Site preparation
Weed membrane, edging, and gravel loss
Measure after edging plans are clear and allow for losses around borders and irregular shapes.
Plan edging, membrane, and gravel losses before measuring the finished area for a gravel project.
Edging changes the finished area
The calculator should use the area that will actually be covered with gravel. If edging, sleepers, kerbs, planters, drains, or stepping stones reduce the finished surface, measure after those decisions are made. That avoids ordering for an area that will not receive gravel.
- Exclude fixed features that will not be covered.
- Measure inside the edging line rather than the rough excavation line.
- Split complex areas into sections and add the results.
Membrane is not a substitute for depth
A membrane may help separate the gravel from soil, but it does not remove the need for a consistent gravel layer. Shallow gravel can still look patchy, expose fabric, or move away from edges. Use the calculator result as a quantity estimate, then check the product and site conditions.
- Choose a depth that hides the base consistently.
- Add an allowance for cuts, corners, and small spills.
- Keep spare material for topping up after the gravel settles.
Preparation checks
| Check | Why it affects quantity | Action |
|---|---|---|
| Edging line | Defines the finished area | Measure inside the edge. |
| Membrane visibility | Can show through shallow gravel | Test a realistic depth. |
| Uneven ground | Creates low spots | Use average depth or add allowance. |
This is an estimate. Site conditions, compaction, and aggregate type can change the final quantity.