Guides · 2026-10-26
Best Shed Base Options & Cost Calculator (Plastic Grid vs Concrete vs Timber)
Compare plastic grid, timber bearer, paving-slab and concrete shed bases for UK sheds and log cabins, with 2026 cost ranges for 6x4, 8x6, 10x8 and 12x10 footprints.
A cheap shed on a bad base is a rotten floor in three winters. The base has to be level, larger than the floor by a few centimetres, and able to keep the joists off wet soil. These four methods cover almost every UK shed, summerhouse, greenhouse and cabin.
The four bases
- Interlocking plastic grid plus geotextile membrane and pea gravel (ProBase, EcoGrid and similar). About £18–£28/m². A competent DIYer can lay a small one in a couple of hours. It is permeable and rot-proof, and it suits sheds and light summerhouses up to about 28mm logs. It is not the base for a 44mm cabin or a garage.
- Pressure-treated timber bearer frame on adjustable risers or ground spikes. About £15–£25/m². Useful on ground that is slightly out of level, and it keeps the floor joists in the air. The bearers themselves must be the treated timber, not the shed floor pretending to be a base.
- Paving slabs on sharp sand over a MOT Type 1 sub-base. About £30–£45/m². The classic solid footing for 8x6 and 10x8 sheds and for greenhouses. The slabs must not rock. A greenhouse that twists will crack glass.
- Poured concrete pad: 100mm of concrete over 100mm of compacted MOT Type 1, with a damp-proof membrane. About £65–£110/m². This is the base for heavy 44mm-and-up log cabins, insulated garden offices and wooden garages. It is overkill for a 6x4 overlap shed.
Cost by footprint
Areas used here are the same floor areas as the rest of the site: 6x4 = 2.23m², 8x6 = 4.46m², 10x8 = 7.43m². A 12x10 is 11.15m² (12 × 10 × 0.092903). Add a little extra gravel and membrane beyond the floor, and treat the top of each range as the realistic delivered DIY cost rather than the bag price alone.
| Footprint | Area | Plastic grid | Timber bearers | Paving slabs | Concrete pad |
|---|---|---|---|---|---|
| 6x4 | 2.23m² | £40–£65 | £35–£55 | £70–£100 | £145–£245 |
| 8x6 | 4.46m² | £80–£125 | £70–£110 | £135–£200 | £290–£490 |
| 10x8 | 7.43m² | £135–£210 | £110–£185 | £225–£335 | £485–£820 |
| 12x10 | 11.15m² | £200–£310 | £170–£280 | £335–£500 | £725–£1,230 |
How to choose
Match the base to the wall, not to the discount. A plastic grid under a 19mm or 28mm cabin, or under any ordinary shed, is a sound DIY job if the ground is dug level and the membrane stops the gravel disappearing into the soil. A 44mm office, a twin-skin room or a wooden garage should be on concrete or an engineered equivalent the manufacturer will warrant. Greenhouses want a square, untwisting base — slabs or the maker's own steel base — because glass does not forgive a diagonal.
Calculator
| Method | Rate | This footprint |
|---|---|---|
| Plastic grid | £18–£28/m² | £80–£125 |
| Timber bearers | £15–£25/m² | £67–£112 |
| Paving slabs | £30–£45/m² | £134–£201 |
| Concrete pad | £65–£110/m² | £290–£491 |
Questions buyers ask
- Can I put a 44mm log cabin on a plastic grid base?
- No. Plastic grid bases at £18–£28/m² are for sheds and light summerhouses up to about 28mm. A 44mm cabin, insulated office or wooden garage wants a concrete pad at roughly £65–£110/m².
- How much does an 8x6 shed base cost?
- About £80–£125 for a plastic grid, £70–£110 for treated bearers, £135–£200 for paving slabs on Type 1, and £290–£490 for a 100mm concrete pad. The 8x6 floor is 4.46m².
- Does the shed price on Shed Deal Hub include a base?
- Only when the retailer includes it in that product. Most timber sheds are sold without a base. Greenhouse bases and plastic grid kits are listed separately under shed supplies.
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