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How to build a wooden shed base

6th February 2017

A wooden shed base is cheap, easy to install, and is a perfectly adequate foundation for smaller sheds.

Take a look at our guide to building a wooden shed base. From designing your base and ordering your wood, through to full instructions for constructing your wooden base, here's everything you need to get started.

For the downloadable .pdf version of this guide, just click the button below:



Is a wooden base suitable for your shed?

A wooden base is sufficient for most smaller sheds. It’s basically a simple wooden frame, strengthened with crossbeams, onto which you build your shed. Check the weight of your shed and its contents. If you intend to install a large garden building - anything larger than 10 x 8 feet - or store a lot of heavy equipment, consider a paving slab or concrete base instead.

At a glance

  1.  Choose the right location for your shed
  2.  Lay out all the components
  3.  Assemble the frame
  4.  Fix the frame into the ground
  5.  Assemble your shed on your new base

You will need

  • Pressure-treated, rot-resistant timbers
  • 4 x galvanised metal ground spikes and L-shaped brackets
  • Screws, drill and bits
  • Tape measure
  • A lump hammer
  • Spirit level
  • A friend - this is a two-person job!

How much timber?

You can either order pressure-treated, rot-resistant timber cut to the lengths you require from your local timber merchant - or save time with a purpose-built kit. For a small shed, 4 x 2 inches should be a sufficient width and depth of timber - but check with your supplier.

If you are using a kit, you will already have everything you need, cut to the correct size. Kits are available in various sizes to match common shed footprints, and come complete with metal ground spikes, support bracket and screws.

For, say, an 8 x 6 foot shed, you will need two 8 foot timbers and four 6 foot timbers. The two longer ones will cap the ends of the four shorter ones, which will be spaced equally at 2 foot intervals as strengthening crossbeams, to form a grid.

Choose the right location for your shed

wooden garden building on wooden shed base
Make sure you’ll be able to get all the way around your building to maintain it.

Give some thought to the optimum spot for your shed. A wooden base may be less permanent than a concrete one, but it would still be a hassle to move it later. Think about natural light, access (can you get all the way around your shed, playhouse or summerhouse to treat the wood or paint it?), and availability of services such as wi-fi or power.

Once you’ve found the ideal location, make sure the ground is level.

You can build the shed base itself elsewhere if needs be. Choose anywhere that’s large and flat enough to build it comfortably, such as an area of lawn. But check you’ll be able to move the completed frame into position later. Remember, your finished frame will be heavy, so don’t give yourself too far to carry it, and get a friend to help.

Lay out all the components

timbers for wooden shed base laid out
A wooden shed base kit laid out on flat ground ready to assemble.

Roughly lay out the timbers and other components ready to build your wooden frame. Arrange the shorter timbers on the ground, narrow side down, evenly spaced along the longer timbers, which should cap either end of the shorter crossbeams to form a grid.

You should also have four metal ground spikes - one for each corner - some metal L-shaped brackets, and screws which may come in varying sizes. Check the instructions that come with your kit to make sure you have everything you need before you start.

Assemble the frame

wooden shed base being assembled with screws
Screw the frame together. Always drill pilot holes to prevent wood from splitting

Once you've measured up and drilled your pilot holes, simply screw the frame together to complete your base. Measure the diagonals, from corner to corner. If everything is correctly aligned, they will both be the same length. If they’re not, secure one corner, then with the lump hammer, gently tap the frame into alignment.

Measure and mark both longer timbers with a pencil where the crossbeams are to be attached to it. Pre-drill two holes at each point you’ve marked. This will help to prevent the wood splitting when you screw the timbers together.

Fix the frame into the ground

fixing a wooden shed base to the ground
Hammer the spikes until flush with the top of the frame.

Make sure the ground is level. Put the base where you want your shed to go (get some help to carry it into position), and fix it to the ground. Take each metal spike and place it flush against the wood inside a corner of the frame. Hammer it into the ground. When the top of the spike is level with the frame, screw it to the wood.

In each corner place an L-shaped plate against the inside of the long capping timber close to the spike you’ve just attached: one side against the wood, the other on the ground. Hammer the plate to flatten it against the ground until the top is flush with the timber. Screw the plate to the frame, and repeat for each corner. These L-plates help to keep your shed level.

Use your spirit level to make sure the frame is level on both axes. If it’s not, hammer the corner spikes further into the ground as required.

Assemble your shed on your new base

garden shed on wooden shed base with floor bearers
Add floor bearers if your shed doesn’t come with them built in.

You now have a strong, secure, level base on which to build your shed. What’s more, your shed will be raised off the ground, which will help to protect it from the elements.

Many sheds come with floor bearers already fixed to the underside. These are smaller timber bearers - usually 3 x 2 inches - that run perpendicular to the timbers of your wooden frame. If yours doesn’t, it’s worth adding some (at intervals of 16 to 24 inches) to allow air to circulate and prevent damp. Just fix them to the base before you start building your shed.

A wooden frame is a quick and easy way to build a shed base - it’s a job you should be able to complete in an afternoon. Once installed, and properly maintained, your shed will give many years of hassle-free use.


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