How to Build a Shed Base: A Guide

A shed base is, obviously, an essential component of any shed. Knowing how to build a shed a base isn’t something that anyone is blessed with automatically. In fact, most of us are going to need some guidance on how to build a shed base as it is perhaps the most important step in ensuring the structure and steadfastness of your shed. It needs to be properly made in order to give your shed a solid foundation.

In this guide we cover the installation of three different types of shed base. Whichever’s best for you, make sure it’s perfect with Garden Buildings Direct and your shed will last a long, long time.

Step 1: Plan Where Your Shed Will Go

build-a-shed-base-1-plan-where-your-shed-will-go (1)
BillyOh Expert Tongue and Groove Apex Workshop with Dual Entrance
  • Make sure there’s access for delivery and access to all sides for maintenance and applying wood treatments etc.
  • Consider surrounding area conditions, such as foliage and young trees that may grow in the future.
  • A well-lit area is best if the building is to be used as a workshop.
  • The view of your garden from the planned area for summerhouses.
  • Consider whether you intend to run an electrical supply to the building.

Choose the Type of Base

It is crucial to provide a level and dry foundation for garden sheds. Never assemble a shed on an unsound base, otherwise you’ll run the risk that the screw holes connecting the wall panels won’t line up. For larger buildings, especially if you’re going to use the shed as a workshop, a full concrete base is your best option. But if you don’t want to fork out for concrete, you have two other options:

  • Eze Base
  • Paving Slab Base

Note: Whichever method you choose, we recommend that you have a 2” (5 cm) lip around the base of your shed. To calculate the size of base required for the particular building you wish to build, add 4” to the overall base dimensions, to ensure an adequate base size for your shed.

How to Build an Eze Shed Base

Most of our garden sheds come with the option to purchase an Eze base. This is our recommended base for most sheds, due to it’s ease of installation.

The Eze Base is made up of a wooden floor surround, supported by wooden bearers which span the depth of the shed. It can be fixed into soil or soft ground via sharp-ended wooden plinths, which are supplied with the base. Make sure that wherever you are planning to install it, the ground is level.

Watch the video below to see exactly how to install an Eze base.

How to Build a Concrete Shed Base

You will need:

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

1. Mark Out Your Base

Decide first where you will be placing your garden shed. Make sure to plan for a 2m gap between the shed and any boundaries. Using pegs and string, mark out the base 2 inches (5 cm) larger than the area of the building on each side.

Finally, test the size by measuring the two diagonals to ensure the area is square.

2. Level off the Area

Concrete requires 3” (7.5 cm) of compacted hardcore (all-in ballast or other crushed rubble/gravel) underneath the 3″ 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” (15 cm), to allow for the hardcore layer and 3” (7.5 cm) of concrete. Level the area with a rake and spade and remove the pegs.

3. Create a Levelled Hardcore

Set up a levelled formwork. This involves measuring, cutting and fitting timber to the shape of the base in order to contain the concrete.

Check diagonal measurements to ensure the formwork is square and level as this will determine whether your shed base is 100% sturdy. Next, 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.

4. Add the Concrete

Mix concrete using one part cement to five parts all-in-one ballast, or use bags of dry-mixed concrete and just add water.

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. Use a sawing motion slowly over the entire surface of the freshly laid concrete.

If wet weather is forecast, cover the concrete with polythene for 24-hours. In warm weather, cover the base with damp sacks and sprinkle them with water over the 24-hour period, this will ensure the drying concrete will not shrink and crack.

The result will be a smooth, solid and level base – the perfect foundation for the construction of a garden shed.

How to Build a Slab Shed Base

You will need:

  • Pegs and string
  • Flat Face Paving Slabs
  • Building sand
  • Standard cement (all in Ballast, cement & water)
  • Rake
  • Tape measure
  • Spade
  • Rubber mallet
  • Sweeping brush

1. Mark Out Your Base

Decide first where you will be placing your garden shed. Make sure to plan for a 2m gap between the shed and any boundaries. Using pegs and string, mark out the base 2 inches (5 cm) larger than the area of the building on each side.

Finally, test the size by measuring the two diagonals to ensure the area is square.

2. Dig, Level off and Rake the Area

Strip the topsoil and dig out to a depth of approx. 2.5” (7 cm) to accommodate the base. Level the area with a rake and remove the pegs and string.

3. Mix the Cement

Mix together one part cement to eight parts building sand for a dry sand and cement mix. Spread this evenly, ensuring that the mix sits approx. 4 cm in depth. Be sure it is level.

4. Lay the Paving Slabs

Starting from one corner and working outward, lay the slabs by tapping down on the centre of each slab with a rubber mallet. Using a spirit level, ensure all the slabs are square, level and firmly butted together for a solid base.

5. Double-Check the Base Is Level and Flat

The completed base should now be level and square. Conduct a final check with a long, straight-edged piece of timber to check if the base is level from each corner.

Also, measure the diagonals to finally check that the base is square. Brush off any excess dry sand/cement mix which could hinder the levelling of the shed. The result is a smooth, solid and level base.

Will I Need Help to Build My Base?

Constructing the foundation for your garden shed is a fairly hassle-free task for a single person to complete. When it comes to actually assemble the shed, we do recommend an extra person is on hand for lifting and placing roof and wall panels in place.

Disclaimer: Please note that this guide is intended to present general information regarding the subject. All information indicated are representative and not exhaustive, which means that the results may vary depending on your item, its size, complexity and other circumstances. This is only advice and we do not accept responsibility for any problems you may have whilst following this guide, it is only a representation and not a definitive guide. When in doubt, please ask your manufacturer before proceeding.

Like this post - why not share it?
Share on Facebook
Pin on Pinterest
Tweet about this on Twitter
Share on LinkedIn

What do you think ?

Also on Garden Buildings Direct