How to Build a Log Cabin: Our Real Build, Step by Step
Building your own garden log cabin is one of the most rewarding DIY projects – and with good planning it is well within reach. In this guide I show you, step by step, how we built our own log cabin: from the strip foundation and the interlocking log walls to the pent roof, windows, doors and an insulated floor. Every photo is from our real build, no stock or AI images.
Quick answer: A log cabin is built in four stages:
1. Base: level the site with batter boards, cast concrete strip foundations and fit treated timber bearers on a damp-proof layer.
2. Walls: cut the logs to length, notch the corners and stack them course by course.
3. Roof: fit the rafters, lay tongue-and-groove roof boards and cover them with two layers of bitumen felt.
4. Fit-out: windows and doors with a settlement gap, then an insulated floor and ceiling.
Most detailed step guides linked below are currently available in German only. English versions of the key steps are being added.
Planning permission and location
Before you buy timber, check the rules. Whether a garden building needs permission depends on where you live and on its size, height and position on the plot. In England, many garden buildings fall under permitted development, but there are limits – for example on height near the boundary. In the US, local building codes and zoning rules apply. We built our cabin in Germany, where the regional building regulations decide. Whatever your country: ask your local authority first, and plan the distance to the boundary before you set out the foundations.
Our experience after 20 years
Our log cabin is now more than 20 years old. It has survived severe storms and every kind of weather, and to this day shows no damage from damp. This guide gives you the full overview of how to build a log cabin from solid interlocking logs yourself.
The base
1. Batter boards and water level
Whether you build a log cabin from scratch or assemble a kit, the base must be level and square. To set out the foundations and transfer heights we used batter boards with string lines and a simple water level (a clear hose filled with water) – accurate to about a millimetre over long distances. How to set up batter boards »
2. Concrete strip foundations
The most common log cabin bases are a concrete slab, concrete pads and strip foundations. We chose strip foundations: the timber does not sit on the ground or in the wet, and air can circulate underneath. That is the best structural protection against rot and the main reason our cabin is still sound after 20 years. A base of paving slabs with a damp-proof layer also works, but usually does not last as long. How we poured the strip foundations »
3. Timber base frame
A strip of bitumen felt goes on top of the foundations as a damp-proof course. The treated timber bearers for the floor sit on top of it. Notch the bearers where they cross and treat every cut end. Position the frame so that rainwater cannot run in between the timber and the felt. Building the timber base frame »
The log walls
4. Preparing the logs
With a log cabin kit, the logs come pre-cut and you only need to sort them according to the plan. Our tongue-and-groove logs were all 5 m (16 ft 5 in) long, so we first cut them to length and then cut the notches for the corner joints. Detailed guide (German)
5. Raising the walls
We prepared the logs in batches, so that any mistake would show up early, and raised the walls log by log. Take care not to damage the tongue and groove – a damaged joint lets in wind and water. Detailed guide (German)
The pent roof
6. Seats for the rafters
Before the roof goes on, the rafters need a solid connection to the walls. We notched the top log at every rafter position. The rafters cannot slide, they bear on their full width, and the rafter spacing of 60 cm (about 24 in) sets itself almost automatically. Notching the top log »
7. Notching the rafters
Most garden cabins have a pitched (apex) roof. We chose a pent roof instead: it looks almost like a flat roof, but slopes to one side with an overhang, so rainwater runs off to the eaves. The rafters need a notch – a birdsmouth – where they sit on the walls, cut at exactly the roof angle. A sliding bevel is the best tool to transfer that angle. How to cut a birdsmouth »
8. Fitting the rafters
We planed and sanded the rafters, cut them to length and cut the rafter ends at a slight angle. That cut runs across the grain at an angle – you need a good saw for it; a jigsaw will not cut it straight. Then the rafters were set on the walls and fixed. Detailed guide (German)
9. Wall-to-roof junction
With the rafters in place, the top course of logs on the side walls had to follow the roof slope so that the walls close flush with the roof. We transferred the angle with the sliding bevel to the table saw and ripped the logs lengthways at that angle. Detailed guide (German)
10. Canopy: supporting long rafters
Our rafters project more than 2 m (6 ft 6 in) beyond the walls to cover the later deck. To stop them sagging under snow, we added posts and a supporting beam afterwards. Better: plan this support from the start, and have even a simple roof structure checked by a structural engineer. Detailed guide (German)
11. Roof boards
A green roof would have looked nicer, but its weight would have been too much for our cabin. We sheathed the roof with tongue-and-groove boards, rough-sawn and planed on one side. Lay them so that the tongue and groove still engage after the timber has fully dried and shrunk. How to lay T&G roof boards tight »
12. Roofing felt
Once the roof edges were finished, we applied two layers of bitumen felt: first a sanded underlay felt fixed with felt nails, then a torch-on cap sheet. Torch-on felt needs a gas burner and a bit of practice – if you are not confident, use a cold-applied system or bitumen shingles instead. Detailed guide (German)
Windows, doors and interior
13. Fitting the windows
Windows are the trickiest part of a self-built log cabin. If the logs are not completely dry, every log loses height as it dries – the whole wall settles. Our 220 cm (7 ft 3 in) high walls dropped by about 5 cm (2 in). Kit cabins usually use drier timber and move less, but they move too. A window fixed rigidly to the logs will jam or crack, so it needs a frame that lets the logs slide and a settlement gap above it. Detailed guide (German)
14. Fitting the doors
To get a wide opening without an expensive custom door, we fitted two standard timber back doors side by side. Make the opening generous: our logs later shrank so much that we had to trim about 2 cm (3/4 in) off the top of the opening. Detailed guide (German)
15. Fitting the door lock
Last come the lock cylinder and the handles. When buying a euro cylinder, the door thickness and the distance from the lock to the outside and inside faces decide the size, so that it neither sticks out nor sits too deep. Detailed guide (German)
16. Floor sub-frame
Because our cabin stands on strip foundations, air flows freely underneath. To stop that air from chilling the floor too much, we fitted an additional sub-frame of battens underneath the floor. How we built the floor sub-frame »
17. Insulated floor
Between the floor joists we fitted wood-fibre insulation boards and ran the electric cables in the void. The floor itself is sanded OSB board, screwed to the joists and sealed with a one-component clear varnish – hard-wearing and cheap. Insulated log cabin floor, step by step »
18. Insulated ceiling
We wedged 4 cm (1 1/2 in) polystyrene boards between the rafters and held them in place with battens from below. The battens also carry the tongue-and-groove cladding boards of the ceiling. If you plan to heat your cabin, think about condensation and vapour control before you close the ceiling. Detailed guide (German)
19. Deck in front of the cabin
If you want a deck in front of your cabin, plan it together with the base: in our case the base frame also carries the larch decking. We chose European larch instead of tropical hardwood. Detailed guide (German)
Our log cabin: workshop and hobby room
Our cabin has stood for many years now and we are very happy with how it has held up. With an old wood-burning stove inside, we can use it almost all year round – as a workshop, and as the perfect place for an evening of cards.
Frequently asked questions
Do I need planning permission for a garden log cabin?
It depends on where you live and on the size, height and position of the cabin. In England, many garden buildings fall under permitted development, but there are limits on height, size and distance to the boundary. In the US, local building codes and zoning rules decide whether you need a permit. Always check with your local authority before you start.
What is the best foundation for a log cabin?
We chose concrete strip foundations. They keep the timber off the ground, allow air to circulate under the floor and stop the wood from standing in the wet – the best protection against rot. After more than 20 years our cabin shows no damp damage at all.
How much do log cabin walls shrink?
Quite a lot if the logs are not fully dry. Our 220 cm (7 ft 3 in) high walls settled by about 5 cm (2 in). Windows and doors therefore need a settlement gap above them and must not be fixed rigidly to the logs.
Which roof is easiest for a self-built log cabin?
A pent roof (mono-pitch roof) is the simplest: the rafters run in one direction, there is no ridge, and rainwater drains to one side. We covered it with tongue-and-groove roof boards and two layers of bitumen felt.
This guide is the English version of our German article Gartenhaus selber bauen.