Shed Bases
Poured to last.
C28/35 ready-mix delivered to your garden. From 0.5m³ upwards. With our volumetric mixers, pay only for what's poured. Instant price in 60 seconds.
The Mix You Need
C28/35 High-Strength Mix
- Mix grade
- C28/35
- Slump
- 75mm (workable)
- Aggregate
- 20mm
- Recommended depth
- 100mm
- Sub-base
- 100mm Type 1 MOT
- Typical volume
- 0.5-2.0 m³
Volume Guide
How much for your shed?
Based on a 100mm slab. Most shed manufacturers specify a base 100mm wider than the building on each side.
6×4 ft shed
1.8m × 1.2m
6×8 ft shed
1.8m × 2.4m
8×6 ft shed
2.4m × 1.8m
8×10 ft shed
2.4m × 3.0m
10×12 ft shed
3.0m × 3.6m
Why It Matters
Get this right and you won't redo it for 30 years
- A shed lasts as long as the base it sits on. C28/35 at 100mm outlives anything you put on top of it.
- Compacted Type 1 underneath stops the slab from rocking and the shed door from dropping out of square after the first wet winter.
- A 1200-gauge DPM under the slab keeps timber bearers and stored items dry, no rotted floors, no rusted tools.
- Volumetric mix means you only pay for what's poured. No surplus to skip, no shortfall halfway through the pour.
Step by Step
How to prepare & pour
Mark the footprint + 100mm
Take the shed footprint from the supplier instructions and add 100mm margin on every side. Mark with pegs and string lines.
Excavate 200mm
Dig down 200mm (100mm sub-base + 100mm slab). Remove topsoil and any soft spots, you want firm undisturbed ground beneath.
Compact Type 1 sub-base
Whacker-plate 100mm of Type 1 MOT in 50mm lifts. The top should be level and ring solid under the plate.
DPM & formwork
Lay 1200-gauge DPM over the sub-base with 150mm overlap at any joints. Set timber shuttering to finished slab level, checked with a spirit level.
Order & pour
Use our calculator for exact m³, we include 10% wastage. Pour direct from the chute, tamp with a straight-edge, float smooth.
Cure for 7 days
Walk-on hard after 24 hours but wait 7 days before you put the shed up. Full cure 28 days, by then it's bombproof.
FAQ
Common questions
Do I need reinforcement in a shed base?
For most domestic sheds under 10m², C28/35 at 100mm without mesh is fine on a well-compacted Type 1 sub-base. Above 10m² or on clay soil, drop A142 mesh in on 50mm spacers.
Can I put a shed on paving slabs instead?
You can, but slabs move and channel loads unevenly. A poured concrete base is 3× the lifespan and ends up cheaper than replacing a rotted shed floor.
How long before I can put the shed up?
7 days. Walk-on in 24 hours, full cure 28 days. Erecting a shed loads the slab lightly, so a week is plenty.
How much concrete do I need?
Multiply length × width × 0.1 for a 100mm slab. An 8×6 ft base (2.4 × 1.8m) = 0.43m³. Order 0.5m³ to allow for wastage. Use our calculator for exact volume.
Is a shed base different from a summerhouse base?
Same spec, C28/35 at 100mm. Summerhouses tend to carry more load (insulation, glazing, furniture), so for anything heavier than a tool shed we keep 100mm minimum and consider mesh.
Can you pump into a rear garden?
Yes. If we can't chute direct, we arrange a pump as part of the booking. Reaches up to 30m+ over obstacles. Call 024 7636 1448 for a pumped quote.
Ready to order?
Instant price in 60 seconds. Next-day delivery subject to availability. With volumetric, pay only for what's poured.