Guide written by:
Jeremy, construction site supervisor, Cardiff
Garden sheds couldn't be easier to set up. Simply assemble and screw down the flooring, cladding and roof, checking everything is straight as you go. Finish by gluing and nailing down the roofing felt. For a more secure foundation, you can install your shed on a concrete base. Read on for our full installation guide!
- Checking your equipment
- Preparing the ground
- Building the frame
- Laying the roof
- Fitting the door
Preparing to install your garden shed
Garden sheds are a great option for storing your garden tools, setting up a little DIY workshop or even just enjoying an extension of your home. Quick and easy to set up, sheds provide a practical and cost-effective alternative to more extensive building work. What's more, there's also less paperwork involved!
Garden sheds are typically sold in kits which come with all the materials and equipment you'll need. The floor joists, wall cladding, purlins and roof cladding are usually supplied cut to size and grooved for easy assembly. This means that only limited carpentry skills are required.
Depending on your structure, you may need to think about laying a concrete base. If this is the case, a certain amount of building knowledge is required in order to create a strong and even foundation with the right dimensions.
When assembling your shed, make sure you read the installation manual carefully. You'll need an drill alongside some nails and a hammer. A tapping block is often provided with the kit to help you fit your parts together. These tools should be used alongside a wooden or rubber mallet. Most importantly, you'll need to know how to follow instructions and be able to use a cement mixer, drill and hammer.
Approx. 4 hours for a 4m² shed
Number of people required
1 or 2 people
1. Checking your equipment
2. Preparing the ground
3. Building the frame
4. Laying the roof
5. Fitting the door(s)
Tools and equipment
As mentioned, you will ideally want to install your shed on a concrete base to protect it from damp and to ensure a level and stable foundation for the structure. To do this, you'll need some basic building tools and equipment:
- a mallet, posts and tapping block (for formwork);
- a cement mixer, shovel and wheelbarrow;
- a straight edge and spirit level;
- trowel and smoother;
- a drill / electric screwdriver with appropriate drill and screw bits;
- hammer and mallet (wood or rubber);
- a carpenters try square;
- wood glue and neoprene glue (for the roofing felt)
Installing a garden shed in five stages
1. Checking your equipment
5 tips for easy installation
- First of all, open the packages in your kit and make sure everything is present and in good condition.Then organise your workspace: arrange your cladding, roof materials (purlins and cladding), floor joists (if your kit includes a wood floor), door(s), window(s) and hardware. Make sure to check the wood as if the kit has been stored awkwardly, some planks may no longer be straight. Your boards may come with wane (where the bark edge gets into the lumber). If this happens, organise your planks so the wane is not on show. If necessary, replace a board or two; this shouldn't set you back much.
- Round up all your fixings and make sure you aren't missing any screws. Manufacturers can underestimate the size of screw: they can either be too short or have a thread that is too fine. Do not hesitate to size up your screws if the thickness of the wood allows.
- Some sheds are somewhat lacking in strength. There's nothing stopping you from adding an extra post to reinforce the corners, a crossbar along a wall or even brackets at the weakest points of the structure.
- Not all garden sheds come with locks. It is strongly recommended to install a lock system as sheds can contain valuable items such as lawnmowers and hedge trimmers.
2. Preparing the ground
Your garden shed must be placed on a flat, stable and solid surface. Ideally, you should install it on a concrete base. If you already have concrete in place, be sure to check that it is level.
Allow an extra 20-30 cm of concrete around the sides of the shed. For example, if your shed measures 3 metres in length, make sure your base is around 3.4-3.6 metres long. Lay your concrete to a thickness of about 15 cm. The use of wire mesh is recommended.
Metal foundations for garden sheds
It is also possible to find metal foundations for garden sheds. These foundations consist of a metal framework that is laid on the ground before the shed is installed over the top.
Please note that metal foundations cannot be used to replace concrete. However, if you do not plan on laying a concrete base, a metal base is better than nothing!
3. Building the frame
Laying the floor
Adding a wooden floor to your garden shed is usually optional.
- This flooring will rest on joists which are installed directly onto the concrete base. Space out your joists according to the manufacturer's recommendations.
- Check the diagonals to make sure the frame is straight.
- You also have to check that the joists are sitting level using your spirit level or chalk line.
- It is essential that your joists are spaced out evenly. Use a template if necessary. If no cross braces have been provided, you can add some at equal intervals between your joists.
Assembling the cladding
Once the floor joists are all in place (if you have opted for flooring), you can start assembling your cladding. Shed cladding usually features a tongue and groove system for easy joining.
To ensure your structure is solid, nail your cladding diagonally or screw the boards to each other. It is recommended to pre-drill your holes using a small wood bit.
Lay the first three courses. At this stage, you should check that the walls are at right angles using a try square and ensure that the structure is level.
Use the tapping block provided to interlock the boards. Continue to assemble the cladding up to a height of about 1.5 metres, then check your structure is level once again.
Use your tapping block to make sure your boards are locked tightly and to avoid marking the wood.
Fitting the window and door frames
The next step involves assembling the frames for the door(s) and window(s).
- Always follow the instructions provided to assemble the frames.
- Check that the frames are solid and aligned correctly.
- They can then be fitted into the empty spaces in the timber structure.
Finishing the cladding
Once the doors and windows are in place, you can finish assembling the cladding. Once this is done, check that the walls are still perfectly perpendicular. Ensure the whole structure is level and that the door and window frames are fixed solidly in the walls.
Fitting the gables
Shed gables often come pre-assembled. They can simply be inserted onto the last board at either end of the shed. It is essential that are fitted correctly onto the structure. If they slot perfectly into place the first time – great! If not, use your tapping block to make sure your cladding is aligned properly. Screw the gables into place once everything is lined up properly.
4. Laying the roof
Installing the purlins
Purlins are horizontal beams designed to support the roof surface. They are inserted into pre-cut slots in the gables. Use a wooden or rubber mallet to make sure they are properly slotted into position. Check that they are level, then nail them down.
Installing the roof cladding
The roof cladding forms the surface of the roof and is usually installed using a tongue and groove system. These boards are nailed directly onto the purlins. A very small gap (about 1 mm) should be left between each board. Check throughout the process that the boards are lined up correctly at the ridge as well as at the eaves.
Fitting the fascia boards
Fascia boards are finishing elements that are installed at the base of the roof cladding. They are nailed down at intervals of 40 cm where the boards end at the eaves. Boards can also be nailed to the gables and these are known as bargeboards.
Laying the roofing felt
If your kit comes with a roll of felt, use one of the fascia boards to help you cut it to the right length. If it comes in pre-cut sections, then you needn't bother!
Start by laying the strips of felt along the bottom of the roof on each side. Slowly work your way up to the ridge. The final strip must cross over the apex to ensure watertightness. Glue the felt onto the roof cladding. To be on the safe side, you should then nail the roofing felt down. The strips should be spaced out at 20-30 cm intervals with nails spaced 10 cm apart.
5. Installing the door(s) and window(s)
Fitting garden shed doors
Doors usually come pre-assembled. All you need to do then is hang them onto the hinges in the frame. You may sometimes have to add handles. This shouldn't prove too difficult as the doors usually come with pre-drilled holes meaning you simply need to screw everything down. You can add a lock afterwards if one is not provided as part of the kit.
Fitting the expansion joint covers
As you've probably noticed, there is usually a slight gap between the tops of the window and door frames and cladding surrounding them. This space acts as an expansion joint. Most kits come with special boards to hide these gaps without actually filling them (allowing the wood to expand without cracking or splitting).
Want more tips for your DIY projects? Follow our editors' advice and check out their other guides:
Garden shed buying guide
Masonry tools buying guide
Hammer buying guide
Cement mixer buying guide
Drill accessories buying guide
Screwdriver bits buying guide
How to maintain your garden shed
Drill bits buying guide
Guide written by:
Jeremy, construction site supervisor, Cardiff, 131 guides
Electrician by trade, I first worked in industrial estates where I installed, wired and fixed a large number of electrical installations. After this, I managed a team of electricians for this type of work. 10 years or so ago, I turned to building and construction. From the modest family home, to gyms and theatres; I have been able to coordinate, audit and organise all sorts of construction sites. for 4 years now, I am restaoring and bulding an extrension to a bungalow in the heart of the welsh countyside. My experience in manual work and my knowledge means I am proud to be of service. Terraces, interior design, roofing, plumbing, electricty, anything goes! We have, my wife, daughter and I, built almost everything we have from scratch! So to answer all of your questions, and to orientate and advise you on coosing your tools? Easy!