Our DIY Garden Room Build

We had been thinking about doing some sort of DIY cabin or garden room build in the area behind our garage for a while, so when we spotted a garden room that was exactly what we were looking for in the Dunster House sale, we decided to go for it! We’ve built a conservatory and a few sheds in our time, so we were happy to tackle it ourselves. While it’s not completely finished yet, here is our experience of the build process and our thoughts so far.

Why A Garden Room?

The area behind our garage had always been a bit of dead space in our garden. When we first moved into the house a few years ago, the area housed a trampoline and an old children’s playhouse that the previous house owners had left behind. Once they were removed we were left with a good sized area of relatively flat garden, that we didn’t really know what to do with.

The space before we started

Building a garden room appealed for lots of reasons – we could use it as a home-office, maybe as a garden bar, and just generally be ‘out’ when we were ‘in’.

Which Garden Room?

We were looking for a DIY garden room to build for quite a while. We looked at various options from lots of different manufacturers, and even considered building our own bespoke version. However we kept coming back to Dunster House as they have a large range of garden rooms and cabins, and they come with a variety of options, depending on how you want to use them. We went for a 4m by 3m ‘Terminator’ cabin. This log cabin is perfect for the space we had available. It also came with proper double-glazed windows and doors. We also opted to have the insulated roof and floor as upgrades, as well as 45mm thick log walls. Hopefully these extras will make the garden room useable all year round.

We also purchased the Rapid Grid Foundation system from Dunster House as this seemed like the simplest way of providing a stable base for the cabin.

The Build – Foundations

In preparation for the garden room’s arrival, we needed to prepare the ground. As per the Rapid Grid instructions, we needed to make sure that the ground was level and stable. This meant digging down as our ground was a little high behind the garage and moving a lot of soil. This was probably the hardest part of the whole build!

Once the ground was level, we were able to lay the weed membrane and the Rapid Grid foundation system down. This was super-simple as it all just clipped together. We ordered a large bag of pea-shingle from a local builder’s merchants and filled up the grids with it. We kept checking as we went that the whole thing was still level.

Laying Down The Cabin Bearers

Our garden cabin delivery

Once the garden room had been delivered (the delivery was helpfully arranged so that all the pieces were roughly in the right order for us – a big bonus!) We set to work on our build. The first pieces to be laid down were the bearers. These are the pieces of wood that the whole thing sits on – so they are pressure treated as they are in direct contact with the ground (albeit sitting on the rapid grid foundation in our case).

Once these were in position and we were happy these were level, we secured the bottom layer of cabin logs to them. We kept measuring the diagonals when setting this first layer of cabin logs in place as it was vitally important that the whole thing was square.

Building Up The Garden Room Walls

The next several layers of logs simply slotted together, so we were able to speed through building up the walls really quickly! Once we had reached up to the cabin window height, we added a couple of extra courses of logs on each side, and then simply slid the complete window frame (with the window already fitted into it) into the gap. The door frame had to be assembled but then similarly slid into position. We kept checking that the corners of the cabin were square as we went along. It was helpful to have a rubber mallet on hand to give the corners a knock here and there where we needed to keep them in line. Within a couple of hours, we had completed the log cabin walls and were up to the eaves.

The cabin walls taking shape

Building The Cabin Roof

Once we had reached eaves height on the garden room, it was time to fit the roof rafters. I have to say I wasn’t involved in this part – my husband did this on his own. They slotted into place in much the same way as the side walls. I imagine they must have been quite heavy!

Once the rafters were in place it was on to nailing the roof boards in place. These fitted tongue and groove style. Our garden room build was taking shape!

The cabin with the beginnings of a roof.

The next part was adding the roof insulation. These came in the form of several large panels – which were really heavy to get up on to the roof. Once they were up though, it was just a case of screwing them down. Although heavy, the panels were very easy to cut to fit when needed.

The cabin with a partially completed roof.

Finally it was a case of wrapping the whole thing in a waterproof membrane and then nailing down roof felt on top. We also added soffit boards to give the garden room a much more ‘finished’ look.

The Garden Room Floor

We were on to the home stretch! As we had ordered upgraded insulation for the cabin, we needed to fit insulation panels between the bearers before we could lay down the floor boards. This insulation was in the form of foil wrapped foam panels – very light and easy to cut. The panels were cut into strips to fit in-between the bearers and then clipped in place. They then sat level with the bearers – again, very straight forward. There are pressure treated panels that fit on the end of the bearers to close the insulation off from the outside.

insulation slotted between the cabin bearers.
The floor insulation poking out from under the floorboards
The cabin floorboards.
The floorboards were laid on top of the bearers.

Once the insulation was in place, the floor boards could go down. Again, these are tongue and groove style and simply nail to the bearers.

Painting The Cabin

As our garden cabin was supplied un-treated, we have had to paint it ourselves. Whilst this is time consuming (not gonna lie!), it gives us the opportunity to personalise our garden room’s look to how we want it.


Our garden room build is now pretty much complete! We managed the whole thing just my husband and myself, with a little bit of help from our 12 year old son. Overall it was a pretty simple DIY. Just requiring an ability to use a drill and a hammer and a hand saw. The most important parts were taking the time and having the patience at the beginning to make sure that everything was square and level. This meant that all of the log sections were then able to slot together easily. At times we found some of the instructions a little bit confusing – but nothing we couldn’t figure out between us!

We have been really impressed with the quality of the materials supplied by Dunster House. Particularly the fact that given there were a large number of parts required, everything was there. In fact there are spare parts for some things.

Whilst there is obviously still much more to be done to the garden room, now the build is complete – I can’t wait to start fitting out the inside and start using it!