Concrete
Volume + bag count for slabs, footings, posts
m
Reading 3 m
m
Reading 3 m
mm
Reading 100 mm
Sets the right reinforcement, DPM, and sub-base for the job.
Use ready-mix for jobs over ~1m³ — cheaper & faster than bags.
%
Reading 10 %
Compacted Type 1 spreads load and stops settlement.
Results
Volume needed
0.99m³
Bags needed
80bag
Sub-base
1.03m³
Area9 m²
Net concrete volume0.9 m³
With waste0.99 m³ (+10%)
Sub-base (100mm)1.03 m³
Imperial35 ft³
Suggested Materials
25kg general purpose concrete bag
Covers 0.99 m³ inc. 10% waste
80 bag
MOT Type 1 sub-base (bulk bag ~0.6m³)
100mm compacted · 1.03 m³ loose (inc. 15% compaction)
2 bag
25kg Sharp sand bag (blinding)
15mm blinding layer over Type 1
11 bag
DPM 1200-gauge (damp-proof membrane)
Inc. 150mm lap & turn-up at edges
11 m²
A142 mesh sheet (4.8m × 2.4m)
Lap 1 full square (~150mm). A142 = 6mm bar on 200mm grid.
1 sheet
Mesh chair / spacer (50mm)
Keeps mesh in middle 1/3 of slab
18 pc
100×25mm treated softwood (formwork)
Plus 50×50mm pegs every 600mm
14 m
Estimates use standard UK trade rules of thumb. Always check the bag/spec on the day.