Concrete for Shed Footings (4 Pad Footings)
Many sheds don't require full slabs, instead using pad footings at corner positions to support bearers. This approach uses less concrete, simplifies construction, and suits sheds where a full floor isn't needed. Here's how to calculate concrete for standard four-pad shed footings.
Standard Pad Footing Dimensions
For typical garden sheds, 400x400mm pad footings at 300mm depth provide adequate support. This size handles loads from small to medium sheds effectively. Larger sheds or those storing heavy equipment may require bigger footings, as specified by the shed manufacturer or an engineer.
Concrete Volume for Four Footings
Each 400x400x300mm footing requires 0.048 cubic metres of concrete. Four footings total 0.192 cubic metres, or approximately 0.21m³ with wastage. This equates to 23 bags of premix concrete, a manageable quantity for DIY installation.
Excavation and Preparation
Dig square holes slightly larger than footing dimensions to allow formwork installation. Remove loose material from hole bottoms and compact the base. Place 50mm of compacted gravel in each hole for drainage before pouring concrete.
Stirrup Bracket Installation
Most bearer arrangements use galvanised stirrup brackets set into the wet concrete. Position brackets accurately to match bearer spacing and ensure they're level with each other across all four footings. Use string lines stretched between corner positions to verify alignment.
Level Consistency
All four footings must finish at the same level for bearers to sit correctly. Use a dumpy level, laser level, or water level to establish consistent heights. Natural ground slopes require adjusted excavation depths to achieve level footing tops.
Council and Compliance
Sheds over certain sizes require council approval, including footing specifications. Check local requirements before proceeding. Even exempt-development sheds may need to comply with particular standards for wind rating and footing design.
Need Different Specifications?
Use our footing calculator to enter your exact dimensions. You can also explore our slab calculator if you're considering a full slab instead of footings.