How to build your own log cabin garden office

Save ££££ by building your own garden office. If you’re looking to create some extra space at home then a log cabin in your back garden could be the answer. In this post I’m going to show you how to build your own and save thousands off the price of a professionally installed garden office. This step by step guide will show you all the different elements required to accomplish this job in the simplest and cheapest way possible. Forget the £15k+ price tag of a garden building supplier and build your own for as little as £5000.

Your own garden office can be as big or small as you like it. You just need to use your imagination a little bit and work within the confinements of you property. For this build I’d like to show you how a log cabin kit can provide the main structural element of your build, making it faster and cheaper than trying to build from scratch. My building has been purchased from Garden Buildings Direct based in the UK. It’s provided me with a fantastic looking structure that can easily be modified to suit my needs as a garden office.

My modifications include electricity, decking area, insulation, internal finishing and a custom paint job. These buildings can also be extended with your own materials or by purchasing one of their lean-to add-ons. You can select different roofing via their website, or again, add your own. At some point down the line I’d like to add some thin slate tiles to the roof to really make this building pop. But for now I’m on a bit of a budget.

Planning

You should understand the buildings restrictions from your local authority before you do anything. Read these carefully to ensure your building doesn’t breach planning restrictions or it could get taken down. The first port of call for this would be the online planning portal. If you are still unsure after checking this then it’s worth contacting your local authority to double check any details.

Now you know your restrictions it’s time to get in the garden with a tape measure and start measuring up. Where is you building going to go? Think about things like:

Where the sun sets and rises,
Are there any over head or underground electrical wiring to avoid?
Are there any water drainage points, pipe works or gas pipe works to avoid?
How level is the ground?

Select your design

With a suitable location found it’s time to select your perfect design. I decided to go with the BillyOh Kent Garden Office as it looked great and was available in the size I wanted. (4m x 3m) I liked this log cabin design as it provided a flexible space that could be easily divided into two sections.

There are many other designs available in the log cabin kit section from BillyOh. You just need to find which one your prefer and use a little imagination with regards to the colour and surrounding area. And remember, these buildings are all fully customisable, both through the website and by your own constructive creativity. Add sections, join two buildings together, cut through walls, add your own style roofing. The possibilities are endless with these building kits.

Building a log cabin base

One thing you don’t get when buying a log cabin kit is a base. So you’ll need to make your own. You have three options here, each with their pros and cons.

A solid concrete base. This will provide the strongest and longest lasting base for your office. It is however expensive and more challenging to build. Look on Youtube for some great guides.
A patio style base. Similar to the concrete base in terms of strength and durability but you will require this to be build on a level surface. If your planning on building your log cabin on a sloped area of your garden then this might not be the best idea. Unless you have access to some heavy excavation machinery.
A wood frame base. This can be the easiest and most cost effective method. It also allows you to build in sloped areas of the garden if you wish. It won’t last as long as a solid base but if you install it correctly and treat it regularly it will last 20+ years.

I’m going to show you how I built my wooden frame base for this log cabin garden office. I chose this base as I’m working to a budget, have a slight slope in my garden and I’m working alone.

How to build a wooden frame base for your log cabin

Make sure the base is bigger than the overall size of your log cabin. I decided to have a small decking area at the front of mine and stuck with standard size construction timber to make things easier. My base measured 4.8m x 3.6m. Joists were spaced about 500mm apart. I used support posts in each corner, 2 at the front and 2 at the back. Additional support posts were used in the middle and breeze blocks help add support in other areas to save money. Here is a quick run down on how to build the base. A materials list can be found further down.

Step 1. Lay the outer edge pieces to find the corners

How to build log cabin wooden frame base step 1 — As you can see I have left the old shed base in place and worked around it.
Some ground works have been completed to level out the ground.

Once finished with the base I’ll need some grass that grows fast to repair the muddy ground. Fast growing grass seed should only take a few weeks to grow back and will get these patches back to normal in no time.

Step 2. Dig holes for the support posts

Digging holes for support posts log cabin — Dig a 60cm deep hole for each corner post. 40cm wide.
Place about 10cm worth of 20mm gravel in the bottom. This provides support, strength and drainage.

Step 3. Fit the support posts

Support post on wood frame for log cabin — Treat the wood with creosote before going any further.
Place the wooden post into the hole. (No need to cut it just yet)

Wooden support post log cabin cement — Pour 1/3 water into the hole.
Add a bag of Postcrete to the water and stir with a stick.
Quickly level out the post with a spirit level. The mix should set within 10 minutes.
Fix the joists and cut the top off the post with a hand saw.

Step 4. Fix the joists to the the support posts

Log cabin wooden frame support post and joists — Use 80mm screws to fix the joists to the wooden posts.

3 screws per fixing point log cabin wooden frame — Add 3 or 4 screws per fixing point. Drill 4mm pilot holes to prevent splitting wood.

Step 5. Fit the rest of the joists and add additional support

Wooden frame base for log cabin fit joists — Using 100mm screws, fix the joist in equal intervals. Roughly 500mm apart.
There are 7 internal joists and one either end. 9 in total.
Add breeze blocks for support. (or dig additional holes for posts.)

Step 6. Add joist bridges and weed protection

Complete wooden frame base for log cabin — With all the joist in place, add a few joist bridges to add strength. (2 more 3.6m)
Finally cover the frame with weed protection barrier. This can be fixed in place with a staple gun.

You should now have a strong wooden frame base on which to build the log cabin. The bearers for the log cabin will run lengthways across the wooden frame.

Materials required for this log cabin wooden frame base

Here’s a list of all the materials I’ve used on this wooden frame base.

Material and retailer link	Quantity	Cost each	Total cost
C24 Sawn Treated Timber 47mm x 150mm x 4.8m	2	£33	£66
C16 Sawn Treated Timber 47mm x 150mm x 3.6m	9 + 2 (11)	£19.80	£218
Treated Incised UC4 Fence Post Green 100mm x 100mm	3	£24	£72
Bullet Gold Wood Screw 5.0 x 100mm Box of 200	1	£30	£30
Blue Circle Ready to Use Postcrete 20kg	4	£6.64	£26.56
Gravel and Shingle Trade Pack 20mm	4	£3.47	£13.88
4Trade Creocote Dark Brown 4L	1	£15.60	£15.60
Weed Control Landscaping Fabric 1m x 20m	1	£24.60	£24.60

The total cost for this log cabin wooden frame base was £466.64

Now it’s time to start work on the log cabin.

How to build a log cabin, a step by step guide

Following the instructions carefully and referring to the technical documentation is the key to success with this BillyOh log cabin kit. Take your time and check measurements carefully.

Here is an example of the log cabin instructions provided with a BillyOh kit: BillyOh Kent log cabin assembly instructions

Step 1. Organise the wood pieces into equal size lengths

BillyOh wood lengths log cabin — Organise all the pieces of wood into equal lengths. This will help speed up the build process.
Also organise the fixings.
You can now quickly access what you need, when you need it.

Step 2. Lay the bearers and first wall pieces

Log cabin bearers and lower wall — Lay the bearers roughly in position.
Lay the first wall sections and square off the corners. (Use large set square)
Measure the width of the doorway using the dimensions from the technical drawings.
Screw these sections to the bearers.
Screw the bearers to the wooden frame to hold everything in place.

TOP TIP – Double check your measurements at this stage. Once you go past this point it’s very difficult to go back without taking everything down! Measure the door width and the length of the internal wall in 3 places.

Step 3. Build up the walls until the bottom of the window

log cabin walls lower section — Add pieces to the walls one by one.
There should be 6 pieces at the front window.
5.5 pieces at the side window.

Step 4. Lay the floor boards

Log cabin flooring — I’ve added a layer of insulation underneath the floorboards.
The boards are nailed into place starting from the narrower end.

log cabin floorboards cutting — Mark and cut out this section using a jigsaw.
The final piece will also need to be cut length ways to fit.

Step 5. Continue adding wall pieces and add window frames

log cabin window frame — Build up walls to 4 pieces above the bottom of the window.
Tap the window frames into place with a rubber mallet.
If it is tight, place a piece of wood on top of the frame and hit with a rubber mallet.
Do not hit the internal section of the frame. It could break.

Step 6. Continue building up the walls

Log cabin walls complete — Build the walls to the top. You will require a ladder for this part.

Step 7. Add the purlins

Add purlins to log cabin walls — Add the purlins to the walls and screw then into place.
Make sure they overhang equal lengths are either end.

Step 8. Fit the roof boards

log cabin roof insulation — I’ve added a layer of insulation.
Screw the roof boards into place.
I found it easier to do this on top of the roof once a few boards where in place.

Step 9. Windows and doors

Log cabin windows and doors — I purchased the double glazing option for my log cabin.
These are easily fitted using the supplied fixings.
Take your time and measure carefully.

fitting door furniture — Fit the door furniture to finish

The great thing about these buildings is that you can upgrade anything, including the windows and doors. The standard double glazing windows that come with the set are pretty basic so you can easily order some upgraded frames to make the building really stand out. Some timber sash windows would really make a big difference to the overall look, feel and improved thermal insulation properties for this building.

Step 10. Fit the internal sealing strips

log cabin internal sealing strips — Fit the internal sealing strips with screws.

Step 11. Protecting the exterior

Paint log cabin — I’ve painted my log cabin this Midnight Blue colour.
You can pick whatever exterior wood paint you wish.
Ensure this is done as soon as possible.

Paint the log cabin — Paint the whole outside with as many layers as possible.

Step 12. Add the roofing felt

log cabin roofing — Start on the lower edges of the roof and roll out the felt.
Tack this into place. Continue on the apex section until the roof is covered.

Step 13. Decking area

log cabin decking area — Cut the decking boards to length and fit to the joists of the wooden frame. 32mm boards should slide nicely under the wall sections.

log cabin finishing touches — Add decking boards to the front section.
Stain the boards using a decking stain or paint.
Add the facia boards to the roof.

Find this Kent Log Cabin Garden Office here

The Interior of the log cabin

This part of the project is currently in progress with an expectation to finish in the summer of 2022. The electrics have been run and fed up through the floor and basic lighting has been added to the interior for now.

Here is a list of jobs to complete this project and turn this into a beautiful, cosy work space.

Insulate the walls
Fit plasterboard to the walls
Fit power outlet points
Lay laminate flooring
Add furniture

Stay tuned for updates on this project. We’re looking forward to finishing this and making the most of our new office space away from the busy home environment.