Putting a shed on soil typically requires preparing a stable, level base to ensure the shed's longevity and structural integrity. While various base options exist, a common and durable method involves creating a concrete foundation directly on the prepared soil.
Why a Base is Crucial for Sheds on Soil
Placing a shed directly onto bare soil is highly discouraged. Soil is unstable; it shifts, settles, retains moisture, and can lead to the shed sinking unevenly, racking the frame, and promoting rot in the base and floor. A proper base provides:
- Stability: Prevents the shed from shifting or sinking.
- Level Surface: Ensures the shed is square and structurally sound.
- Drainage: Lifts the shed floor away from ground moisture, preventing rot and dampness.
- Pest Protection: Can help deter rodents and insects from nesting under the shed.
One effective way to create a stable base on soil is by laying a concrete slab, as outlined in the provided reference.
Creating a Concrete Base on Soil
Building a concrete slab is a robust method for installing a shed on soil. It provides a solid, level, and durable foundation. Here are the key steps involved, based on the provided reference:
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Mark Out the Area:
- Using pegs and string, mark out the base area.
- It's important to allow 5 cm extra space around the planned shed dimensions to provide a sufficient working area and ensure the shed fits comfortably on the finished base.
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Prepare the Ground:
- Dig a hole that is 15 cm deep and level across the entire marked area. Remove all topsoil, grass, and large stones.
- Insert a wooden framework around the perimeter of the dug area. This frame will act as formwork to contain the concrete and ensure the slab edges are clean and straight. The top of the framework should be level with the desired final surface height of the concrete slab.
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Add Sub-Base Material:
- Add a 7 cm deep level layer of stone or hardcore (such as crushed concrete or gravel) into the dug-out area, within the wooden framework. This layer provides essential drainage and a solid, compactable base for the concrete. Compact this layer thoroughly using a plate compactor or hand tamp.
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Pour and Finish the Concrete:
- Add the concrete cement mix into the formwork on top of the compacted hardcore layer.
- Spread the concrete evenly and level off the surface using a straight edge (like a timber board) resting on the formwork. Ensure the concrete is flush with the top of the wooden frame.
- Allow the concrete to fully set and cure according to the concrete manufacturer's instructions. This can take several days depending on the mix and weather conditions. Keep it damp during the initial curing period to prevent cracking.
| Step | Depth/Detail | Purpose |
|---|---|---|
| Mark Out Area | 5 cm extra space | Room for error/working area |
| Dig Hole | 15 cm deep, level | Remove soil, create space for base layers |
| Insert Wooden Framework | Perimeter of dug area | Contain concrete, define slab edges |
| Add Stone/Hardcore Layer | 7 cm deep, level | Drainage, stable sub-base |
| Add Concrete Mix | Fill to top of formwork | Create solid, level foundation |
| Allow to Set | Fully set (days) | Achieve full strength and durability |
Once the concrete base has fully cured, you can safely position and assemble your shed on this stable and durable foundation.
