Slabs for a 7 × 5 ft shed base, by slab size
A 7 × 5 ft shed is a store with room for a potting bench or the garden furniture over winter. The base here is 2.1 × 1.5 m, converted at 0.3 m per foot, which leaves it marginally smaller than the shed floor as most shed makers ask (check your shed's instructions). The layout column shows where whole slabs fit with tight joints; the last column is the paving calculator's count with 10 mm joints and 10% for cuts and breakage.
| Slab size | Layout | Slabs by area | Slabs to buy |
|---|---|---|---|
| 600 × 600 mm | Needs cuts | 9 | 10 |
| 450 × 450 mm | Needs cuts | 16 | 17 |
| 400 × 400 mm | Needs cuts | 20 | 21 |
| 300 × 300 mm | 7 × 5, no cuts | 35 | 37 |
| 600 × 300 mm | Needs cuts | 18 | 19 |
| 900 × 600 mm | Needs cuts | 6 | 7 |
A size that 600 mm slabs do not divide into
A 2.1 × 1.5 m base is three and a half slabs by two and a half, so one row each way has to be cut. Counted by area it is 9 slabs if every offcut is used, and the calculator's 10 with 10 mm joints and 10% extra gives you a slab in hand for a cut that goes wrong.
If you would rather not cut, 300 × 300 mm slabs fit this base exactly: 7 by 5, which is 35 slabs. Small slabs have more joints to keep level, so take extra care screeding the bed flat.
Sub-base and bed for 2.1 × 1.5 m
| Layer | Quantity |
|---|---|
| MOT Type 1 sub-base, 100 mm | 0.73 tonnes |
| MOT Type 1 sub-base, 150 mm (soft ground) | 1.09 tonnes |
| Sharp sand for a 30 mm sand bed | 0.16 tonnes |
| Or a 40 mm mortar bed at 6:1 | 0.24 tonnes of sharp sand and 2 bags of 25 kg cement |
Quantities include 5% extra. Check for buried services before you dig, using the free LSBUD service. Shed base options compared weighs slabs against concrete, a plastic grid and a timber frame, and the concrete version of this base is on how much concrete for a 7 × 5 ft shed base.
Want to change anything else? The calculator above is the full Paving Slab Calculator (UK): edit any number and the results update instantly.
Tools & materials for this project
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Frequently asked questions
How many slabs do I need for a 7x5 shed base?
10 slabs of 600 × 600 mm, with some cut. The 2.1 × 1.5 m base is 3.15 m², which is 9 slabs by area, and the extra covers 10 mm joints and 10% for cuts and breakage.
What goes under the slabs for a 7x5 shed base?
About 100 mm of compacted MOT Type 1 (0.73 tonnes for this base) and a 30 mm bed of sharp sand (0.16 tonnes). On soft ground use 150 mm of sub-base, which is 1.09 tonnes.
Do I have to cut slabs for a 7x5 shed base?
With 600 × 600 mm slabs, yes: the 2.1 × 1.5 m base is 3.5 by 2.5 slabs, so allow 10. With 300 × 300 mm slabs it is exactly 7 by 5 (35 slabs) with tight joints and no cuts.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check the Building Regulations and your supplier's guidance before ordering.