Understanding how to prepare for a concrete shed slab is the key to building a strong, level, and durable foundation that will support your shed for decades. Proper preparation not only prevents future cracking or sinking but also ensures your shed remains secure in all weather conditions.
Steps on How to Prepare for a Concrete Shed Slab
1. Measure and Mark Out the Area
Begin by measuring the exact dimensions of your shed base. Use string lines and stakes to mark out the area, checking carefully that it is square and level. A well-marked layout ensures the slab will be the correct size and aligned properly with your shed.
2. Excavate and Compact the Ground
Excavate the marked area to the required depth, removing all soft soil, grass, or debris. Once cleared, compact the ground thoroughly to create a stable foundation. This step prevents future subsidence that could cause your shed slab to shift or crack.
3. Install Base Layer and Reinforcement
Spread a 100–150mm thick layer of crushed rock or road base and compact it firmly. This provides drainage and stability beneath the concrete. Next, lay reinforcement mesh or steel bars to increase slab strength and minimise the risk of cracking under load.
4. Plan for Anchors and Services
If your shed requires hold-down anchors or has utility connections (such as power or water), position these before pouring concrete. Planning ahead prevents costly modifications later and ensures the shed is securely fastened to the slab.
Pro Tip: Always raise your concrete shed slab slightly above ground level. This prevents water pooling around the edges during heavy rain and helps extend the life of both your slab and shed.