Concrete Bases

A Step-By-Step Guide:
Concrete Base Method
Consider the best location for the your garden shed/garage in terms of:

  • General access (for delivery of garden building, access to all sides for maintenance and applying wood treatments etc.)
  • Surrounding area conditions (Foliage, young trees that may grow in the future etc.)
  • Natural light (a light area is best if the building is to be used as a workshop for example)
  • The view of your garden from the planned area (for summerhouses etc.)
  • Consider whether you intend to run an electrical supply to the building.

Just before you start…..
It’s crucial to provide a level and dry foundation for your shed. It is not practical to assemble a shed on an unsound base, otherwise you are running the risk that screw holes connecting the wall panels will not line up. For larger buildings, especially where the shed will be used as a workshop, a full concrete base is your best option.

Site Visit ………..
You are making an investment into your garden shed/garage and we are happy to call and see your proposed location and advise you on what will give you the best return. After years of supply and fit, we are only too pleased to lend a hand.
We can supply the base if you require and if not, please feel free to use our step by step guide in creating the correct foundation for your garden shed/garage.

A Step-By-Step Guide: Concrete Base Method

concrete3Tools Required:

  • Pegs and string
  • Building sand
  • Standard cement (All-in Ballast, cement & water)
  • Timber for base formwork
  • Tape measure
  • Spade
  • Sweeping brush

Step 1

Decide where to position your shed in an optimal space, allow enough distance from hedges or fences for easy access to all sides. Using pegs and string mark out the base 2 inch (5 cm) larger than the area of the building on each side. Finally, measure diagonally across both sides to ensure the area is square.

Step 2

A concrete base requires 3 inch (7.5 cm) of compacted hardcore (all-in ballast or other crushed rubble/gravel) underneath the 3 inch (7.5 cm) concrete layer. The base can be level with the ground or raised above it. If you want it to be level, excavate the top earth to 6 inch (15 cm), to allow for the hardcore layer and 3 inches (7.5 cm) of concrete. Level the area with a rake and spade and remove the pegs.

Step 3

concrete2.gifSet up levelled formwork. This involves measuring, cutting and fitting timber, to the shape of the base in order to contain the concrete (as shown in the diagram).
Check diagonal measurements to ensure the formwork is square and level, as this will determine whether your shed base is 100% sturdy.

concreteNext, spread a layer of well compacted hardcore (all-in ballast or crushed gravel) and cover with a liberal amount of sand. This needs be well compacted and flattened down, preferably with a compacting tool or roller.

Step 4

Now, mix concrete using one part cement to five parts all-in one ballast, or use bags of dry-mixed concrete and just add water. Remember small amounts of water should be added at a time and mixed into the concrete. Be careful as excessive amounts may make the cement too sloppy and it needs to stay reasonably dry. Spread the concrete evenly and slightly above the formwork. This can be then levelled off with a long straight edge of timber resting on the formwork using a sawing motion slowly (as shown below) over the entire surface of the freshly laid concrete.