How to build a wooden shed base

How to build a wooden shed base

A wooden shed base is cheap, easy to install and provides a perfectly adequate foundation for smaller sheds. From designing your base and ordering your wood through to practical construction tips, this step-by-step guide contains everything you need to get started.

Browse our full range of wooden sheds for the perfect sized storage solution for your garden.

Is a wooden base suitable for your shed?

Constructing a wooden shed base on grass
A wooden shed base should be straightforward to construct

A wooden base is sufficient for most smaller sheds. It’s basically a simple wooden frame, strengthened with cross beams, 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. Work out how much timber you will need
  2. Choose the right location for your shed
  3. Lay out all the components
  4. Assemble the frame
  5. Fix the frame into the ground
  6. Assemble your shed on your new base 

You will need:

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

Step 1: How much timber do I need?

Man laying down timber on grass
Make sure you have all the components to hand before starting

You can either order pressure-treated, or 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 inch timber should be sufficient – but check with your shed supplier.

A kit 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 brackets and screws.

For 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.

Step 2: Choose the right location

Waltons 8x6 Shed on paving slab base
Give yourself plenty of space around your shed for regular maintenance
Image: Waltons 8 x 6 Value Overlap Single Door Apex Wooden Shed

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 or paint the wood?) and availability of services such as wi-fi or power.

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

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.

Step 3: Lay out all the components

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.

Step 4: Assemble the frame

Drilling wooden shed base
Always drill pilot holes before screwing the wood together

Once you’ve measured up and drilled 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.

Step 5: Fix the frame into the ground

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.

Step 6: Assemble your shed on your new base

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. Visit the Waltons blog for advice, tips, and all things sheddie.

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