How to build a garden shed

When you build your own garden shed you can make it to perfectly suit your needs and preferences. We take you through the project step-by-step.

A man standing beside a finished diy garden shed with trees behind it

Do I need a garden shed?

If you have any outdoor space at all, a garden shed is an invaluable addition that will help keep things in order. It will quickly serve as a place for leftover potting soil, empty plant pots and other utensils. It also offers a safe and dry storage place for garden power tools such as lawn mowers, clearing saws and hedge trimmers, keeping them protected against cold, moisture and dirt so that they continue to function correctly, as well as manual tools such as spades and rakes.

It may seem like a daunting challenge, but building your own DIY garden shed just needs a little skill and knowledge and offers the huge advantage that you can adapt it to suit your needs. You’ll need to take some time to prepare, but don’t worry: our detailed instructions take you right from planning your garden shed to completing the build. Our version also has a green roof, so it's much more appealing to look at than a typical shed as well. 

Do you need planning permission to build a garden shed?

My property, my rules? Not exactly. Construction on private property is subject to regulations, and there may be some instances when building a wooden shed requires planning permission. Most typical garden sheds fall under permitted development rules in the UK, meaning planning permission is not needed – but you should make sure your plans meet the criteria. Height restrictions vary slightly depending on where the shed is located, but a maximum height of 2.5 metres will not generally be a problem.

There are a few intricacies to planning laws dependent on your exact situation, so you should look over the current building regulations before you start.

Be a good neighbour

To avoid conflict with your next-door neighbours, you should discuss your plans with them in advance. This gives you the chance to make sure that your garden shed will not cause issues with other property boundaries and will not block anyone’s view.

How to build a garden shed: preparation

Once you’ve established the rules, you can start preparing to build your garden shed. This is a substantial project that will take about 4 to 5 days to complete.

Choosing the right location

Choose a location that is easily accessible for wheelbarrows and large pieces of equipment. Choose a spot where the soil is not too wet or muddy. We also recommend you build on flat ground: although it is also possible to build a shed on a slight slope, levelling the floor requires additional effort.

A person taking a plank of wood from a pile of materials under a tree

Selecting your wood

Softwoods such as Douglas fir, spruce and larch are excellent choices for a garden shed. To keep your shed resilient and protected from the elements, use pre-treated wood and maintain it regularly with a paint-on preservative.

Be sure your construction timber is completely dry before you start using it to build your DIY garden shed – otherwise, the material could warp or even break after it dries.

Tools and Materials you’ll need to build a garden shed

Larch/Douglas fir timber
28 m of 50 x 150 mm
Tongue-and-grooved wooden planks
30 m of 140 x 20 mm; approx. 140 m of 96 x 2.5 mm
Construction timber (spruce/larch/Douglas fir)
at least 59 m of 76 x 50 mm; approx. 8 m of 170 x 22 mm; approx. 7.5 m of 50 x 22 mm; approx. 7.5 m of 78 x 22 mm
OSB (oriented strand board) for sides
approx. total area of 20 square metres of 15 x 1220 x 2440 mm panels
OSB (oriented strand board) panels for roof
2 tongue and grooved panels of 18 x 1220 x 2440 mm
Green roof retention strip
length of 2544 mm
Grit or gravel
Metal roof edge trim
10 m
 2544 mm
with brackets
Pond liner or roofing felt
6 m2
Studded drainage membrane and 2x pieces of root barrier sheet (or all-in-one green roof drainage matting)
6 m2  
Growing medium substrate for green roof and sedum for planting (for green roof shed option only)
(for green roof shed option only)
Countersunk chipboard screw
4.5 x 50 mm, 3.5 x 40 mm, 6 x 100 mm and 6 x 150 mm
9 x concrete-in anchors
with brackets suitable for 50 mm beam plus wood screws to attach them
Screeding concrete
740 mm wide

STIHL tip: Get your OSB panels cut to the size you need at the DIY store.

Materials and tools laid out neatly on a green lawn ready to build a garden shed

Tools and accessories required

Boots, protective gloves and cut protection trousers laid out on grass

How to build a garden shed: step-by-step instructions

A man staking out a shed footprint on grass

Step 1: prepare the area

Use stakes to mark the outline of your shed on the ground. Remove any stones and weeds from inside the area and use a spirit level to check if the ground is even or needs to be levelled off.

Step 2: build pile foundations

When exposed to frost, rain or heavy loads, soil can shift – and this type of movement could warp your DIY shed over time. A solid foundation helps prevent this and will mean your garden shed remains sturdy for years to come. It also means you can create space between the wood and the soil, to allow any water to run off and protect the shed from frost. There are various approaches to making a foundation for a garden shed, including building a full concrete base and using blocks. This method uses concrete piles set into the ground.

A man using a spade to dig 9 holes for pile foundations for a diy garden shed

For a 2 x 2 m garden shed, you should measure and mark the positions for 9 foundation piles, each measuring around 40 x 40 cm. For adequate structural support, the holes should all be 1 m apart. In sandy soils, you will need to use wooden formwork to create square holes. Use a spade to dig each hole to a depth of 70 cm.

A floor joist is positioned in place over the pile holes and rests on blocks, as someone checks it using a spirit level

Use your chainsaw (for example, an MSA 140 battery chainsaw) to saw 3 floor joists to a length of 1.9 metres, using the 50 x 150 mm timber beams.

Mount 3 ground anchors to each joist so that each anchor post will be centred in the middle of a hole. It is important to slightly recess the timber at the point you attach the bracket, otherwise, the mount will not sit correctly, and the full weight of the shed will be distributed across the screws alone. Using wooden blocks to rest the floor joists on, position the joists so that the anchor posts hang centrally in the holes. Use a spirit level to make sure the floor beams are flat and also level with each other.

A man building the timber base frame of a diy garden shed

Pour concrete into the holes to 1 cm below the joists and leave to harden. The wooden blocks will hold the joists in position during this time. As soon as the concrete has dried, you can install the crossbeams. Start by sawing the two outer pieces of timber to 2 m; for the centre support, you will need two pieces measuring 92.5 cm in length.

Evenly fill the squares with grit.

Step 3: install floor

You can now lay a floor over the foundation of your garden shed. You can use a garden pruner, like the GTA 26 to cut the floorboards to length, securing them to a workbench for cutting.

A tongue-and-groove floorboard being screwed to a timber garden shed base

Lay the first board so it rests across three perpendicular joists, and the tongue faces into the shed. Screw it securely to the joists. Then push the groove of the second board onto the tongue of the first – if you can’t easily get a good fit, knock it into place with a piece of scrap wood, taking care not to damage the tongue. Screw the board in place and continue laying the whole floor in the same way. Cut away the overhang from the tongue of the final board.

Step 4: assemble the walls

It is easier to pre-assemble each wall before installing them onto the garden shed base. We recommend you do this on an even, level surface – the base you have just built will work well. Alternatively, you could place several trestle tables together to work on.

These measurements are to create a shed with a single pitch roof, so the front and back wall are the same size (though one has the door in it), and one side wall is taller than the other. Use the 76 x 50 mm timber to build the frames; the lengths you need are given below.

Right shed wall 2000 x 1800 mm frame:

  • 2x 2000 mm
  • 4x 1700 mm
  • 6x 600 mm (crossbeams)
  • OSB-panels

Left shed wall (tall wall) 2000 x 2065 mm frame:

  • 2x 2000 mm
  • 4x 1965 mm
  • 6x 600 mm (crossbeams)
  • OSB-panels

Rear shed wall (slanted top):

  • 6x 550 mm (crossbeams)
  • 1x 1848 mm, (for the base)
  • 1x 1950 mm, cut to an 8° angle at the top
  • 1x 1855 mm, cut to an 8° angle at the top
  • 1x 1775 mm, cut to an 8° angle at the top
  • 1x 1710 mm, cut to an 8° angle at the top
  • 1x 1870 mm for the top bar of the frame, cut to 8° at one end and 82° at the other (the ends should be parallel).

Front shed wall (slanted) with door:

  • 2x 554 mm (for the base)
  • 5x 454 mm (crossbeam)
  • 1x 740 mm (lintel)
  • 1x 1950 mm, cut to an 8° angle at the top
  • 1x 1830 mm, cut to an 8° angle at the top
  • 1x 1775 mm, cut to an 8° angle at the top
  • 1x 1710 mm, cut to an 8° angle at the top
  • 1x 1870 mm for the top bar of the frame, cut to 8° at one end and 82° at the other (the ends should be parallel).

Note: You do not need to angle the horizontal top bars of the two side walls because the roof joists of the garden shed will be notched at these points.

A man screws together a frame-and-panel wall for a garden shed

Saw the 76 x 50 mm beams to the lengths specified above and connect them together as indicated, using 6 x 100 mm screws. The spaces between the vertical wall battens should all measure 600 mm. The spaces between horizontals should measure 600 mm at the bottom and in the middle, and 400 mm at the top – except for the tall left wall, in which the spaces between all horizontal battens should be 600 mm.

Cut the OSB panels to size and screw them to the shed wall frames from the inside using the 3.5 x 40 mm screws.

STIHL tip: Now prepare the door elements in the front wall: screw the laths to the square timber and drill the necessary holes.

A man mounts a pre-assembled wall onto a wooden DIY shed base using temporary supports

Step 5: install the walls

You can now install the pre-assembled walls on the base and screw them together.

First, you need to secure the tall left wall in position with two temporary battens, as shown. Use a spirit level to check that the shed wall is straight before you fix the supports in place.

A man screwing together the assembled walls of a garden shed

You can now put in place and screw together all the walls in turn, using 6 x 100 mm screws. When this is done, the attached walls will effectively form thicker supporting posts at each corner of your garden shed. Only remove the temporary supporting battens when the walls are solidly upright and have been screwed into place. Then, hang the door on the front wall of the garden shed.

Note: For those parts of the frame where it is not possible to drive a screw in straight to connect components, you can simply screw at an angle.

Step 6: prepare roof beams

Now it’s time to make the roof. You will need to make five rafters from the 150 x 50 mm timber. Saw the beams to a length of 2430 mm and cut the ends at angles of 30° and 60° respectively (the ends should be parallel).

A roof beam being notched with a hammer and chisel

To be able to securely connect the roof beams and wall joists, you need to make notches or grooves in the wood. These need to be made at every position that the roof beams meet the vertical posts of the wall frames, at a distance of 20.4 cm to 28 cm from the end of each beam and they should be 76 mm long and 1.5 cm deep. Saw the gaps first and then chisel them out further. Finally, connect the rafters to the support posts using the 6 x 150 mm screws.

STIHL tip: When attaching the roof beams to the sides, use a Forstner drill bit to countersink the screw holes to about 2 cm. This will help prevent the long screws from buckling to the sides under the weight.

A man on a ladder screwing the OSB roof panel of a shed into place

Step 7: mount the roof battens and panel

Screw 8 battens from the same timber, each cut to a length of 438 mm, in place between the rafters and perpendicular to them. Make sure that the top face of the battens are flush with the top of the rafters. Then fix the OSB roof panel in place.

A man fixing a piece of timber cladding vertically in place on the outside of the garden shed frame

Step 8: clad exterior

The next step is to cover the rough structure you have built with a beautiful cladding made from tongue-and-groove panelling. This means that as well as being an attractive garden feature, your shed will also be windproof and weather-resistant.

You can use screws or nails to secure the panelling to the framework. Attaching the panelling so that the joins are vertical means that water can run off easily and will not get trapped between the boards.

Step 9: create roof edges

If you have chosen to give your garden shed an attractive green roof, you now need to make the necessary edging for the roof. This step uses various sizes of timber, as set out below.

For the front and back edges:

  • 2 pieces of 170 x 22 mm construction timber cut to 2500 mm
  • 2 pieces of 50 x 22 mm construction timber cut to 2450 mm
  • 2 pieces of 78 x 22 mm construction timber cut to 2450 mm

For the tallest, left wall edge:

  • 170 x 22 mm construction timber cut to 2544 mm
  • 50 x 22 mm construction timber cut to 2500 mm
  • 78 x 22 mm construction timber cut to 2500 mm
A man mounting a pre-assembled roof edge to a shed roof

Once cut to length, use 4.5 x 50 mm screws to screw the pieces together to form long J-shaped pieces, as shown in the picture. Mount these upside down to the roof, securing them from underneath to form the edges. Leave the right side open for now; this is where you will mount the green roof retention strip.

A man on a ladder screwing a green roof retention strip in place on the roof a garden shed

Step 10: assemble green roof

Secure pond liner to the roof along all 4 sides. Put down a layer of root barrier sheet, then the studded drainage membrane, then another layer of root barrier. Alternatively, you can use a single layer of all-in-one green roof drainage matting. Finally, attach the green roof retention strip to the right edge.

If you are not going to have a green roof on your garden shed, you can simply nail roofing felt to the frame instead.

A man pours growing medium from a bag onto a garden shed roof

Step 11: planting the roof

Distribute approx. 20 cm of gravel along the retention strip and the other edges of the roof, then add a suitable growing medium to cover the rest of the roof. Now you can add the plants.

Robust and appealing sedums (small, fleshy-leaved succulents that spread like a mat) such as the redmoss stonecrop, caucasian stonecrop, goldmoss stonecrop, Angelina stonecrop and the gold fat hen stonecrop are particularly good for roof greening. Heath pearlwort and antennaria will also thrive on your garden shed.

You could simply buy plants from your local garden centre or DIY store for planting on the roof of your garden shed, or, for a ready-made option, you can buy a sedum blanket that is rolled out like turf.

The last step is to fit the guttering, including a drainpipe. If you put a water butt under the pipe, you can easily collect rainwater to water your garden with.

Finished! Your DIY garden shed is now ready for you to fill up with tools and then admire your handiwork! 

A finished DIY timber-clad garden shed with a green roof

Summary: how to build a garden shed

  • With a little skill and knowledge, you can build a sturdy garden shed in 4 to 5 days.

  • Most sheds don’t need planning permission, but there are restrictions on height and area, so be sure to check your specific situation.

  • The best site for your garden shed is a spot where the ground is even, and the soil is not too wet or muddy. The structure should be easy to access with a wheelbarrow or heavy garden tools.

  • Softwoods such as pine, spruce or larch are an excellent choice for building a garden shed. Floor joists made from plywood are also a good option. You should only use pre-treated wood, and be sure to maintain it regularly with the right preservative.

  • Start by building a foundation using concrete, wooden beams and gravel. Then lay floorboards on top and screw them into place.

  • Use a garden pruner to cut the floorboards to length. A powerful chainsaw is better for heftier beams.

  • Always wear personal protective equipment while working with a chainsaw, as directed in your operating instructions.

  • Build the walls individually using a timber frame construction and OSB panels. Then assemble the entire structure, screwing everything together, and install the door.

  • Saw and chisel angled notches into the roof beams, then screw them to the side supports. Add battens and then an OSB panel to the roof
    Clad the outer walls with vertically mounted tongue-and-groove panelling.

  • Build and install shed roof edges and green roof layers. Plant suitable plants, such as the red moss stonecrop or the caucasian stonecrop.

  • Attach guttering and a downpipe.