Slabs for a 6 × 4 ft shed base, by slab size
A 6 × 4 ft shed is the small garden store for tools, a mower and a couple of bikes. The base here is 1.8 × 1.2 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 | 3 × 2, no cuts | 6 | 7 |
| 450 × 450 mm | Needs cuts | 11 | 12 |
| 400 × 400 mm | Needs cuts | 14 | 15 |
| 300 × 300 mm | 6 × 4, no cuts | 24 | 25 |
| 600 × 300 mm | 3 × 4, no cuts | 12 | 13 |
| 900 × 600 mm | 2 × 2, no cuts | 4 | 5 |
Six slabs: the smallest slab base
Three slabs along and two across is the whole base, so there is nothing to cut and very little to carry: 6 slabs, with 1 more if you buy the calculator's 7 to have a spare. The sub-base is 0.50 tonnes of MOT Type 1, which is 1 bulk bag of 0.8 tonnes, and the bed is 0.11 tonnes of sharp sand.
The same base in concrete is 0.24 m³, mixed from 4 bags of cement. At this size the slabs are usually the quicker job, because nothing has to be shuttered or left to harden.
Sub-base and bed for 1.8 × 1.2 m
| Layer | Quantity |
|---|---|
| MOT Type 1 sub-base, 100 mm | 0.50 tonnes |
| MOT Type 1 sub-base, 150 mm (soft ground) | 0.75 tonnes |
| Sharp sand for a 30 mm sand bed | 0.11 tonnes |
| Or a 40 mm mortar bed at 6:1 | 0.16 tonnes of sharp sand and 1 bag 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 6 × 4 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 6x4 shed base?
6 slabs of 600 × 600 mm, laid 3 by 2, cover the 1.8 × 1.2 m base with tight joints and no cuts. Buy 7 to have 1 spare; that is the paving calculator's count with 10 mm joints and 10% extra.
What goes under the slabs for a 6x4 shed base?
About 100 mm of compacted MOT Type 1 (0.50 tonnes for this base) and a 30 mm bed of sharp sand (0.11 tonnes). On soft ground use 150 mm of sub-base, which is 0.75 tonnes.
Is a 6x4 shed base better in slabs or concrete?
Either works. Slabs need 6 of 600 × 600 mm on 0.50 tonnes of MOT Type 1; concrete needs 0.24 m³ (4 bags of cement if you mix it). Slabs can be laid and used the same day.
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.