How to build a concrete base for a new shed
2,676 views Jul 30, 2018
There are many articles showing how to build your own garden shed but why bother when there are so many good ready-made options available. However whatever type of shed you choose, it’s going to need a good base – preferably concrete – and that’s not difficult, even with the most basic of DIY skills.

Once you have planned where your shed will go you need to make sure you have all the right tools and products to complete the job such as:

Pegs and string

Building sand

Standard cement

Timber for base formwork

Tape measure


Sweeping brush

1. Prepare the base

When you do this allow enough distance from hedges or fences for easy access to all sides. Use the pegs and string to mark out a base 2” (5 cm) larger than the area of the building on each side. Make sure the area is square by using a level diagonally across the area

2. Pay attention to the hardcore

Ensure that you have at least 3” (7.5 cm) of compacted hardcore underneath a 3″ concrete layer. The base can be level with the ground or raised above it. If you want it to be level, dig to a depth of 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. Make sure it’s level

Measure, cut and fit 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. Spread the hardcore and cover with a good level of sand. Ensure it is well compacted and flattened using a compacting tool or roller.

4: Next 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. Be careful not to add too much water as this may make the cement too runny.

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.

In extreme weather conditions – both hot and cold – ensure that you base is covered to allow it to cure slowly, minimising the risk if shrinking or cracking – and there you have it – the perfect base for your new shed.

You could of course then decide to build your own shed but as we discussed earlier – why would you want to when there are so many brilliant alternatives that have been prefabricated offsite and ready to be place on your new base.

Talk.Build never makes recommendations but as a starting point you might want to visit:  Sheds