How to Build a Garden Workshop (DIY Workshop Build Guide UK)

Building a DIY garden workshop is one of the most rewarding projects you can take on, but I will be honest, my first attempt was not perfect. After building both a flat pack workshop and later constructing a workshop completely from scratch, I learned exactly what works, what does not, and where money is often wasted.

If you are looking for something smaller or simpler to start with, you can follow my guide on how to build a prefabricated wooden shed step by step, which is a much quicker project.

Whether you want space for woodworking, mechanics, crafts, or storage, this step-by-step guide shows exactly how to build a garden workshop from scratch in the UK using basic tools and affordable materials. I will show you how to build your own workshop, what it really costs, and which approach gives the best long-term results.

Garden Workshop Build Overview

This project shows how to build a DIY garden workshop from scratch using basic tools and commonly available materials in the UK.

Time Required: 3 to 5 days
Skill Level: Basic to intermediate DIY
Typical Cost: £500 to £5,000
Example Workshop Size: 22ft x 10ft

Main Stages of Building a Garden Workshop

1. Build the workshop base
2. Build the workshop walls
3. Build the workshop roof
4. Fit exterior cladding
5. Insulate and wire the workshop interior

Garden Workshop Plans (Dimensions and Layout)

Before building your garden workshop, decide on the size and basic layout. This will save time, reduce waste, and help control costs.

Common garden workshop sizes:

• 8ft x 10ft
• 10ft x 12ft
• 12ft x 16ft
• 22ft x 10ft

Typical DIY workshop layout:

• Wall stud spacing: 600mm centres
• Corner posts: 90mm x 90mm timber
• Floor joists: 400mm to 600mm centres
• Low pitch roof to stay within height limits
• Door opening: 900mm to 1400mm wide

Designing your base around standard OSB sheet sizes (2440mm x 1220mm) helps minimise cutting and waste.

If you prefer to follow ready-made garden workshop plans, I also offer downloadable plans covering multiple sizes and layouts.

Tools Required to Build a DIY Garden Workshop

You do not need specialist equipment to build a garden workshop, but having the right basic tools will make the job much easier and faster.

Essential Tools

• Combi drill
• Impact driver
• Circular saw
• Hand saw
• Spirit level (long and short)
• Tape measure & pencil
• Hammer
• Claw bar or pry bar
• Square
• Utility knife

Helpful Optional Tools

• Workbench or saw horses
• Mitre saw
• Jigsaw
• Cordless nail gun
• Staple gun (for membranes)

Materials

I’ve completed a list of materials at the end of each section so that you can see exactly what I have used throughout the build. I’ve also included a complete materials list at the end of this article.

Step 1 – Build a Strong Base for Your Garden Workshop

To get started, you will need to establish a base. I’ve gone for a raised wooden frame supported on patio slabs. The timber used is quite thin at only 70mm, which helped keep costs down. This is probably the most cost-effective way. Other options might include a paving stone patio base, a gravel base to allow for drainage, a stone wall with cement foundations or a cement pillar-style base.

I first cleared the area and levelled it off as much as possible using a spade and shovel. I then placed the four corner slabs and used the timber and a large spirit level to ensure everything was flat. I’ve used some excess sharp sand from another build to help do this.

If you are working with an uneven surface like a slope, then you will need to dig in one side and raise the other side. You can also use a deck block in each corner and each joining section for the perfect raised platform.

Extra slabs were added to ensure a nice, secure frame. Digging and adding compacted soil and aggregate to ensure all the slabs are even is very important. This can be quite a lengthy process, but it is very important.

The image below demonstrates the basic wooden frame that I have used in my workshop. This wooden frame is topped with 18mm OSB board and will be covered with a moisture barrier membrane.

The size of the base is up to you but bear in mind that the OSB boards come in at 2440x1220mm size. Working with multiples of these can make life easier.

I cut the OSB board using a circular saw.

Once the base has been constructed, then I’d recommend covering it with a weatherproof sheet.

Materials required for building the raised wooden base

• Round edge Whitewood spruce C16 Stick timber (L)3.6m (W)70mm (T)45mm – Quantity 2
• Round edge Whitewood spruce C16 Stick timber (L)3m (W)70mm (T)45mm – Quantity 5
• Round edge Whitewood spruce C16 Stick timber (L)2.4m (W)70mm (T)45mm – Quantity 4
• OSB 3 Board (L)2.44m (W)1.22m (T)18mm – Quantity 4
• Diall Yellow-passivated Carbon steel Screw (Dia)5mm (L)70mm, Pack of 100
• Diall 0.15mm Foam Laminate & solid wood flooring Vapour barrier membrane, 20m² – Quantity 2

You could increase the size of the timber used for the base to provide extra strength and additional space for insulation. Consider a 95mm wide board or even 145mm.

95mm

• Round edge Whitewood spruce C16 Stick timber (L)3.6m (W)95mm (T)45mm
• Round edge Whitewood spruce C16 Stick timber (L)3m (W)95mm (T)45mm

Or 145mm

• Round edge Whitewood spruce C16 Stick timber (L)3.6m (W)145mm (T)45mm
• Round edge Whitewood spruce C16 Stick timber (L)3m (W)145mm (T)45mm

Step 2 – Build the Garden Workshop Walls

Each wall section was constructed using 2×4” timber. These were pieced together, leaving roughly a 600mm gap between each other. This would allow enough space for the insulation.

Each corner post was 90x90mm and provided the support for each wall to be attached to. I put up the 3 walls and left the front wall for a custom size in which the door could be installed.

I screwed 9mm OSB boards to the outer walls and covered these with a breathable membrane.

Normally, you would then put some strips vertically down the outer walls to mount the cladding on, but I didn’t do this to save money. However, I would recommend doing so to allow for air circulation.

Measure the door and build a timber frame to support this. Centre this on the front of the building and complete the rest of the surrounding walls. This can also be finished as per the other walls.

Door and window frames should be built with double thickness timber. Simply join two pieces together to ensure a good strong frame.

I purchased my doors from Wickes: UPVC French doors

You can also find similar windows if you wish to add some.

Cladding is the final step and can be fitted from the roof to the floor. The type of cladding you use is up to you. Log lap cladding or ship lap cladding are both great options. These were simply screwed in using thin 4mm x 30mm screws. Some may wish to nail their cladding on.

Materials for the walls and exterior cladding

• Green Square Fence post (H)2.4m (W)100mm, Pack of 4
• Round edge Whitewood spruce C16 Stick timber (L)3.6m (W)70mm (T)45mm – Quantity 4
• Round edge Whitewood spruce C16 Stick timber (L)3m (W)70mm (T)45mm – Quantity 3
• Round edge Whitewood spruce C16 Stick timber (L)2.4m (W)70mm (T)45mm – Quantity 28
• Planed Spruce Shiplap Cladding (L)3m (W)119mm (T)14.5mm – Quantity 65
• OSB 3 Board (L)2.4m (W)1.22m (T)9mm – Quantity 12
• Diall 0.15mm Foam Laminate & solid wood flooring Vapour barrier membrane, 20m² – Quantity 2
• Breathable Membrane 112gSM 50 X 1m – Quantity 1
• Carbon steel Screw (Dia)5mm (L)70mm, Pack of 100

If you prefer the look of loglap cladding then take a look at these:

• Loglap cladding 121mm x 3.6m

or

• Treated 38×125 loglap

Step 3 – Build the Workshop Roof

Building trusses can be a little tricky and quite time consuming. Ensure the pitch of the roof isn’t higher than 2.4m to stay within building permission regulations. Start off by making one and then replicate that.

My walls were all 2m tall, so the pitch of the roof was only allowed to be 40cm. Notches are cut into each rafter to allow a secure fit to the wall. These pieces were all secured with screws.

Screws (70mm) were inserted down into the top of the rafter and secured to the wall frame.

The top of the corner posts can be cut off when you have the roof rafters in place. Simply use a hand saw and cut at the same angle as the roof pitch.

OSB boards (18mm) were then secured to the rafters. The roof overhangs the walls by about 30cm all the way around. Another waterproof membrane was added to the roof before the felt.

The felt can be rolled out onto the roof and tacked in using clout nails. Make sure you start at the lower edges and overlap each roll by at least 3cm.

Materials for the roof

You can choose which size OSB board you want for the roof. The thicker the better in terms of sound and thermal insulation.

• OSB 3 Board (L)2.44m (W)1.22m (T)18mm – Quantity 6
• Round edge Whitewood C16 CLS timber (L)2.4m (W)63mm (T)38mm – Quantity 22
• Roof pro Green Shed felt, (L)10m (W)1m – Quantity 2
• Breathable Membrane 112gSM 50 X 1m – Quantity 1
• Carbon steel Screw (Dia)5mm (L)70mm, Pack of 100
• Carbon steel Decking screw (Dia)4mm (L)40mm, Pack of 500
• Diall Clout nail (L)12mm (Dia)3mm – Quantity 3

The cladding

Finishing off the walls with suitable cladding is all that’s required to protect you from the elements. There is a great selection available from most local timber merchants. Red cedar is considered the best type of material for this application but it can be quite expensive. You can try a Douglas Fir instead as a cheaper alternative. Take a look at this Timber Merchant for some cut-to-size timber as it has many options available for exterior use. Wood Shop Direct will deliver nationwide but if you are local in Cornwall they are worth a visit for some top-notch advice.

Step 4 – Insulating & Finishing the Workshop Interior

Now it’s time to work on the interior. Running electrical wiring is the first stage. If you’re not familiar or comfortable with this, then hire a professional.

I drilled 8mm holes through the support timbers and fed the electrical wires around the room to the locations I wanted electrical sockets.

I then placed all the insulation into the wall cavities, making sure the electrical cable poked through. I used 50mm Rockwool RWA45 insulation for this job. It’s a great sound and thermal insulator. These insulation sheets should fit nicely into the 600mm wide gaps between the timber frame. To complement this, installing insulated doors helps to maintain consistent temperature control and further prevent heat loss through door openings, which is important for a comfortable and energy-efficient workshop.

I used 2.5mm 3-core for the sockets and 1.5mm 3-core for the lighting. A small 2-way consumer unit was added along with several 13A sockets, lighting switches and pendant fixtures.

Always have your electrical work signed off by a qualified electrician.

The consumer unit must be metal in a workshop.

With electrical wiring run now it’s time to add the insulation.

Now a layer of plasterboard can be fixed to the walls and ceiling. I used 9.5mm plasterboard and 40mm plasterboard screws to fix these to the timber frame.

All the electrical fittings were secured to the walls and tested by a qualified electrician.

Once you have fitted all the plasterboard, you should fill the gaps. You don’t have to skim the whole wall with plaster unless it’s looking very bad. I simply used some ready-mixed plaster, joining tape and a 4-inch knife to join the boards and fill the gaps.

Electrical materials list

Here is a complete list of electrical materials I have used on this project.

• 3 core 2.5mm² Twin & earth cable, 10m
• 3 core 1.5mm² Twin & earth cable, 10m
• 2 way consumer unit (metal)
• 13A 2 gang Switched Metal-clad socket X 3
• 10A 2 way Single Metal-clad switch
• Pendant light fitting or LED White Batten strip light IP20 5600lm (L)1.5m

Running power to your workshop

If you don’t already have power running down to your workshop area, then you will need some armoured cable; the size and load will need to be determined by an electrician. A trench will normally have to be dug to install the cable, and this will be wired into your consumer unit. The armoured cable is also covered in conduit to further protect it.

Interior materials

Finishing and insulating the walls.

• 9.5mm plasterboard square edge 2.4m x 1.2m
• 40mm plasterboard screws
• Ready mix plaster
• Joining tape

You can also add a layer of OSB 3 board for added insulation on the inside.

• OSB 3 Board (L)2.4m (W)1.22m (T)9mm

Finishing off the Workshop

The final job is to paint the interior walls, fit some laminate flooring and finish off the exterior painting. I found a larger paint brush and a roller set, which made things much quicker here.

Here is the paint we used on the exterior: Cuprinol 5 year ducksback Black Matt Fence & shed Treatment 9L

We used a white silk paint on the interior: Dulux Pure brilliant white Silk Emulsion paint, 10L

Interior Furniture and Fixings

I decided to make a couple of simple workbenches and move my table saw workbench into this space. The construction is very straightforward if you want to make these yourself. Alternatively, you may wish to buy something and some racks for storage purposes.

Or build your own. This workbench is setup for mitre saw cutting.

Conclusion

It’s been a great experience building my own workshop. Challenging at times but mostly enjoyable, especially when the weather was nice. I’ve taken a look at some other builds on the internet for inspiration.

Do I Need Planning Permission for a Garden Workshop?

If you stick within the guidelines of the planning permission then you won’t need to apply for any. Here is a simple guide as to what you can and cannot build in your garden.

Check the Planning Portal, or contact your local planning authority before you do anything. The following is an extract from the UK planning portal:

Outbuildings are considered to be permitted development, not needing planning permission, subject to the following limits and conditions:

• No outbuilding on land forward of a wall forming the principal elevation.
• Outbuildings and garages to be single storey with maximum eaves height of 2.5 metres and maximum overall height of four metres with a dual pitched roof or three metres for any other roof.
• Maximum height of 2.5 metres in the case of a building, enclosure or container within two metres of a boundary of the curtilage of the dwellinghouse.
• No verandas, balconies or raised platforms (a platform must not exceed 0.3 metres in height)
• No more than half the area of land around the “original house”* would be covered by additions or other buildings.
• In National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the maximum area to be covered by buildings, enclosures, containers and pools more than 20 metres from the house to be limited to 10 square metres.
• On designated land* buildings, enclosures, containers and pools at the side of properties will require planning permission.
• Within the curtilage of listed buildings any outbuilding will require planning permission.

*The term “original house” means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.

*Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

How Much Does It Cost to Build Your Own Workshop?

The cost of building a DIY garden workshop varies depending on size, insulation level, and whether you include electrics. However, most self-build workshops will fall within an certain price range.

As a general guide:

• Small basic workshop (around 10ft x 8ft): from £500
• Medium workshop with some insulation: £1,500 to £3,000
• Large fully insulated workshop with electrics: £3,000 to £6,000

My own workshop cost approximately £5,000. It measures 22ft x 10ft, is fully insulated, and includes double glazed French doors.

Typical Garden Workshop Cost Breakdown

Item	Typical Cost Range
Base and foundations	£100 to £400
Timber frame	£200 to £800
Cladding	£300 to £1,500
Roof structure and felt	£150 to £500
Insulation	£100 to £400
Plasterboard and interior finish	£100 to £300
Doors and windows	£150 to £800
Electrical materials	£150 to £600

What Affects the Total Cost?

The first step is deciding how you plan to use your workshop. This influences size, layout, and specification.

For example, I built my workshop to support furniture making, so I needed enough space for woodworking machines, workbenches, and material storage. I chose a 22ft x 10ft footprint, a pitched roof, double-opening front doors, and no windows.

By comparison, a pre-made workshop I previously purchased measured 12ft x 10ft and included two sets of double doors and two perspex windows.

Setting your intended use, preferred size, and budget early will make it much easier to design your workshop and control costs.

Is It Cheaper to Build Your Own Workshop or Buy a Manufactured One?

In most cases, it is cheaper to build your own workshop than to buy a manufactured or flat pack workshop of similar size and quality.

From my own experience, I was able to build a large, fully insulated garden workshop for less than the cost of buying a comparable pre made building.

The final price depends on factors such as size, materials, windows and doors, insulation, roofing, and electrics. You could spend as little as £500 on a basic DIY workshop or more than £10,000 on a high specification build.

If you want a cheap workshop, you will need to accept some compromises, such as simpler finishes and reduced insulation. Setting your budget and workshop size before starting will help keep costs under control.

DIY Garden Workshop Materials List (Full Build Summary)

This is a summary of all the main materials used across the entire build.

Base and Floor

• C16 structural timber 70mm x 45mm (various lengths)
• Optional larger timber: 95mm x 45mm or 145mm x 45mm
• 18mm OSB 3 boards (2440mm x 1220mm)
• Vapour barrier membrane
• Paving slabs or concrete pads
• 5mm x 70mm wood screws

Wall Framing

• C16 CLS timber 70mm x 45mm
• 90mm x 90mm fence posts for corner posts
• 9mm OSB 3 boards
• Breathable membrane
• 5mm x 70mm wood screws

Roof Structure

• C16 CLS timber 63mm x 38mm (rafters)
• 18mm OSB 3 boards
• Breathable membrane
• Shed felt
• 4mm x 40mm decking screws
• 5mm x 70mm wood screws
• Clout nails

Exterior Cladding

• Shiplap or loglap timber cladding boards
• 4mm x 30mm exterior screws

Doors and Windows

• UPVC French doors or double timber doors
• Optional windows

Insulation

• 50mm mineral wool insulation (Rockwool RWA45 or similar)
• Optional internal OSB boards (9mm)

Interior Wall Finish

• 9.5mm plasterboard
• 40mm plasterboard screws
• Jointing tape
• Ready mixed plaster

Electrical Materials

• 2.5mm² twin and earth cable
• 1.5mm² twin and earth cable
• 2 way metal consumer unit
• 13A double sockets
• Light switch
• Pendant light or LED batten light

Flooring and Decoration

• Laminate flooring
• Exterior wood treatment or shed paint
• Interior emulsion paint

Optional Extras

• Armoured cable for power supply
• Conduit
• Workbench materials
• Shelving or racking

Pro Tip

Buying timber in bulk and designing around standard sheet sizes can significantly reduce overall material cost and waste.

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Save money on your build

Save money on your build. I’ve been using TopCashback for all my online purchases, which has enabled me to accumulate over £1000 in the last 3 years on all my spending. I simply check TopCashback before making a purchase and use their link to generate money.

Here’s a look at my earnings to date.

To make the most of TopCashback I installed the Google chrome extension browser which notifies me when I am on a site eligible for cashback.

Another great way to save money is to buy in bulk and ensure you get free delivery.

Thanks for reading