Cement Footings for Sheds

There is no hard-and-fast answer, but a good rule of thumb (if using concrete foundation piers) is one shed footing every 8-10 feet. That means an 8×10 shed should have 4 shed footings (if footings are required) while a 16×40 shed should have about 15 shed footings.

Cement footings are an essential component when it comes to building a sturdy and durable shed. They provide a solid and stable foundation, preventing the shed from sinking, shifting, or being affected by moisture. In this article, we will delve into the details of cement footings for sheds, covering the entire process from planning to execution.

Planning the Footings:

Before you begin the construction of cement footings for your shed, it's crucial to plan the project carefully. Consider the following factors:

1. Shed Design and Size: Determine the dimensions and weight of your shed to calculate the required footing size and depth.
2. Local Building Codes: Research the building codes and regulations in your area regarding shed construction, including footing requirements.
3. Soil Assessment: Evaluate the soil conditions to ensure proper load-bearing capacity and drainage. Consult a soil engineer if necessary.

Footing Design:

Based on the shed's size and weight, design the footings to provide adequate support. Consider the following aspects:

a. Footing Type:

Typically, there are two common types of footings: continuous footings and individual concrete piers. Continuous footings are suitable for smaller sheds, while larger sheds may require individual concrete piers.

b. Footing Dimensions:

Calculate the footing dimensions based on the load-bearing requirements and soil conditions. This includes determining the width, length, and depth of the footings.

Gathering Materials and Tools:

To construct the cement footings, you will need the following materials and tools:

a. Materials:

• Cement
  
• Aggregates (sand, gravel, or crushed stone)
  
• Reinforcement bars (if required)
  
• Water
  

b. Tools:

• Shovel
  
• Wheelbarrow
  
• Concrete mixer (if needed)
  
• Measuring tools
  
• Level
  
• Reinforcement cutter (if required)
  
• Trowel
  
• Protective gear (gloves, safety goggles, etc.)
  

Excavation and Formwork:

Once you have gathered the necessary materials and tools, it's time to prepare the site for excavation and formwork:

• Mark the Shed Layout: Use stakes and strings to mark the shed's perimeter and outline where the footings will be placed.
• Excavation: Dig the footings according to the dimensions and depth requirements specified in your design. Remove any rocks, debris, or organic materials from the area.
• Formwork: Build the formwork using wooden boards or metal stakes and plywood. Ensure that the formwork is level and properly aligned with the shed layout.

Mixing and Pouring the Concrete:

With the site prepared, you can now mix and pour the concrete for the footings:

• Mixing: Follow the manufacturer's instructions to mix the cement, aggregates, and water in the correct ratios. Consistency should be thick but workable.
• Pouring: Fill the formwork with the concrete mixture, ensuring that it reaches the desired depth. Use a trowel to level the surface and remove any air pockets.
• Reinforcement (if required): If your design calls for reinforcement bars, place them in the concrete while pouring, ensuring they are appropriately spaced and positioned.

Curing and Finishing:

After pouring the concrete, it's important to allow it to cure properly for maximum strength and durability:

• a. Curing: Protect the newly poured footings from excessive moisture loss by covering them with plastic sheeting or applying a curing compound. Keep the concrete moist for several days, following the curing time specified by the manufacturer.
• b. Finishing: Once the concrete has cured, remove the formwork carefully. Smooth any rough edges or surfaces using a trowel or appropriate finishing tools.

How Much Will the Concrete Slab for My Shed Cost?

As a rough guide, a 150mm thick slab will cost between $90 – $120m² (in rural areas). Although a 125mm thick slab may be adequate in many situations, we believe it is best to go with a 150mm slab as the extra thickness is not overly expensive.

For example, over 100m² of concrete slab, only another 2.5m³ of concrete is required to increase it from 125mm to 150mm thick – which only equates to about $500 difference! It also pays to keep in mind that thinning the slab out under workbenches and work areas requires more preparation, so it is normally more effort than it is worth.

Repairing concrete slabs is also quite difficult, so ensure you don’t skimp on the thickness, as it could cost you more in the long term in maintenance – particularly in high-traffic machinery workshop sheds.

What Do You Put Between Concrete and Shed?

Once you've poured your concrete slab and your garden shed is up, use a silicone sealant like Brick & Concrete Silicone or any other silicone sealant that you prefer, to seal around the inside base of your shed to further improve its water resistance.