How to Measure Your Garden for a Log Cabin

You need a tape measure, some pegs and string, a spirit level and about an hour. Measure the usable space (not just the whole plot), check the ground is level, then add a gap around the cabin for walking, maintenance and delivery. If the numbers don’t match a standard size, that’s fine. We can adjust a cabin to fit your space, so you never have to squeeze a garden around a cabin.

TL;DR

• Measure the usable space, not the whole garden. Fences, trees, paths and drains all take room.
• Mark the cabin out on the ground with pegs and string, then check both diagonals match so the corners are square.
• Check for slopes at every corner. A line level and two stakes will do it.
• Add a clear gap around the cabin and check the route in for delivery, such as gates, side passages and steps.
• Check the height and boundary limits before you order. In England, a cabin within 2 metres of a boundary is limited to 2.5 metres overall.

Table of Contents

• What you’ll need
• Step 1: Sketch your garden first
• Step 2: Measure the usable space
• Step 3: Mark the cabin out on the ground
• Step 4: Check the ground level
• Step 5: Leave room around the cabin
• Step 6: Check the way in
• Step 7: Check the rules before you order
• A worked example
• What to do if no standard size fits
• Our view: measure twice, then choose the cabin
• Ready to turn your measurements into a cabin?
• FAQ
• Sources

What you’ll need

Nothing fancy. Most of this is already in your shed-free garage or kitchen drawer:

• A long tape measure. A 30-metre one is handy for a whole garden, as Gardening Guides suggests. A 5-metre one is fine for a small plot.
• Wooden pegs or garden canes, and a ball of string.
• A spirit level (a phone spirit-level app works too).
• Graph paper and a pencil.
• A friend to hold the other end of the tape. It makes everything quicker and more accurate.
• Your phone, to take photos of the spot from a few angles.

Step 1: Sketch your garden first

Before you measure anything, draw a rough sketch. Don’t worry about neatness. The RHS suggests starting with the house, the boundaries and any fixed objects such as manhole covers, trees, sheds you’re keeping, patios and outside taps.

On your sketch, mark:

• The back wall of the house and any doors or windows facing the garden.
• Fences, walls and hedges.
• Trees, with a note of how wide their branches spread.
• Drain covers, pipes you can see and outside power or water.
• Where the sun is in the morning and afternoon.

Then, as you measure, write the numbers on the sketch. You’ll be glad you did when you’re looking at cabin sizes later.

Step 2: Measure the usable space

The size of your garden isn’t the size of your cabin space. What counts is the open area you can really build on.

For a normal rectangular garden, measure the width and the length with the tape. Do it twice, at different places. Gardens are rarely perfectly straight, and a fence might lean in a little at one end.

Then check the corners. For a plot that should be rectangular, measure both diagonals from corner to corner. Gardening Guides explains that if the two diagonals are equal, the plot is a true rectangle. If they differ, it’s out of square by that difference.

If your garden is out of square, write down the narrowest width you find. That’s the number that decides what fits.

Gardens with curves and odd angles

Most gardens aren’t neat boxes. Adam Frost, speaking for the RHS, says most boundaries have kinks and obstacles, but two simple methods can map any shape: triangulation and offsets. Here’s how they work in plain words.

Offsets. Pick a straight line as your baseline, such as the back of the house or a straight fence. Then, as Jo Hobbs Garden Design explains, measure out from the baseline at right angles to each point on the curve. Take a few readings along any wide feature, say every metre or so. Join the dots on paper and you have the shape.

Triangulation. Choose two fixed points, such as the two back corners of the house. Measure from each one to the spot you want to record, such as the corner of a flower bed. On your plan, draw an arc from each corner using those two lengths. Where the arcs cross is your spot.

The RHS also says that the further you get from the house, the less critical the accuracy is. Near the house, be careful. At the far end of the garden, a few centimetres either way rarely matter for a cabin.

Don’t count space you can’t use

If there’s a pond, a big tree or a raised bed in the way, the land behind it isn’t free space just because it’s inside your fence. Draw a line round everything that stays, and measure only the clear area left over.

Step 3: Mark the cabin out on the ground

Paper plans are good. Seeing the real footprint on your lawn is better.

1. Choose a cabin size you’re thinking about. For example, 4m by 3m.
2. Put a peg in each corner of that footprint.
3. Run string between the pegs.
4. Measure both diagonals. When they match, the corners are square. If they don’t, nudge one peg until they do.
5. Stand inside the marked area. Sit down if you can. Look back at the house.

Gardening Guides suggests using sand, canes, rope or even cardboard boxes, and living with the layout for a fortnight before you commit. You don’t have to wait that long, but a weekend helps. Check how it looks from the kitchen window, where the sun lands, and how much of the lawn is left.

Try two or three sizes. It’s much easier to change string than timber.

Step 4: Check the ground level

A cabin needs a flat, firm base. A garden that looks flat often isn’t, so check each corner.

Here’s a simple way to measure a slope, using the method from No More Digging:

1. Mark the footprint with canes and string.
2. Find the highest corner and call it A.
3. Tie a string at ground level to a cane at A and pull it level to each other corner, checking with a spirit level.
4. At each corner, measure the gap between the level string and the ground. That’s the drop.
5. Write down the drops next to your length and width.

If the drops are small, say a few centimetres, a levelled base usually deals with it. If they’re big, you’ll need to think about digging out the high side or building up the low side. Gardens with bigger falls can need more groundwork, so it’s worth getting the numbers right now.

To describe how steep a slope is, Garden Ninja divides the drop by the length. A 30cm drop over 3 metres is a 1:10 slope. A 60cm drop over 2 metres is 1:3, which is steep enough to need retaining walls.

While you’re there, look for:

• Soft or boggy patches.
• Spots where water sits after rain.
• Water running off roofs or paving towards the site.
• Roots from nearby trees.

Note them on your sketch. A good base is dry, firm and drains away from the cabin.

Step 5: Leave room around the cabin

A cabin that fits to the centimetre on paper is hard to live with. Leave space for:

• Maintenance. You’ll want to reach all four walls to treat the timber. Around 60cm to 1m all round is a comfortable gap.
• Overhanging roofs. Measure the cabin’s roof overhang, not just the walls. It can add a good chunk to the footprint.
• Doors and windows. Check there’s room for the door to open, and for a decking area or a few steps if you want them.
• Trees. Leave space from branches that will drop leaves, sap and the odd twig on the roof.
• Services. If you want power, plan a route for the cable from the house.

If the house has a damp proof course (a line of thicker mortar a few brick courses up), Gardening Guides says any new paving must finish at least 150mm below it. Keep that in mind if your cabin will sit close to the house.

Step 6: Check the way in

This is the step people forget. The cabin has to get from the road to your chosen spot.

Measure:

• The narrowest point of your side gate or passage. Include door handles, meters and bins.
• Any steps, tight turns or low branches on the way.
• The slope of the route, if the garden is on a hill.
• The distance from where the delivery will stop to the building spot.

A kit comes as packs of timber that people carry in by hand, so you don’t need space for a big load. Still, it’s useful to know where the packs can be stored while you build, and whether it’s an easy carry. If access is tight, tell us when you order and we’ll help you plan.

Step 7: Check the rules before you order

Most garden cabins in England don’t need planning permission, but only if they stay within certain limits. These are the main ones. They are for England, and Scotland, Wales and Northern Ireland have their own rules, so check with your local council if you live there.

Which? sets out the main points for garden rooms:

• The cabin must be behind the front of the house (the principal elevation).
• It must be single storey, with eaves no higher than 2.5 metres.
• Overall height must be under 3 metres, or 4 metres with a dual-pitched roof.
• Within 2 metres of a boundary, the whole building is limited to 2.5 metres.
• No balcony, veranda or raised platform.
• It can’t be used as self-contained living accommodation.

The Planning Portal adds that outbuildings together can’t cover more than 50% of the land around the house (excluding the house itself). It also says the rules are stricter in National Parks, Areas of Outstanding Natural Beauty, the Broads and World Heritage Sites, and that a building in the grounds of a listed building isn’t covered.

So as you measure, write down the distance from your marked footprint to each boundary. If it’s under 2 metres, you’ll want a cabin 2.5 metres high or lower. We’ve written more about this in our guides on permitted development rights for garden buildings and planning permission for small log cabins. If your site is in a protected area or you’re unsure, ask your local planning authority before you buy.

A worked example

Let’s say your garden is 12 metres long and your back fence is slightly crooked.

1. You measure the width at three places: 6.2m near the house, 5.9m in the middle and 5.6m at the far end. The narrowest is 5.6m.
2. You want the cabin at the bottom of the garden, so you plan for a 4m by 3m cabin, with 4m running along the back fence.
3. You leave 1m behind for treating the timber and about 1m each side, which uses 6m of width. That’s too wide for the 5.6m at the far end.
4. You move the footprint 3 metres up the garden, where the width is 5.9m, or you drop the gaps to 70cm each side.
5. The fence is within 2 metres, so you choose a cabin no higher than 2.5 metres overall.
6. Your side passage is 85cm at its narrowest, which is fine for carrying packs in by hand.

One evening, one sketch, and you know what fits.

What to do if no standard size fits

This happens a lot. The garden is 5.6m wide at the narrow end, and the cabin you like is 5.8m. Or you want a particular shape to wrap round a tree.

That’s where a bespoke cabin helps. Our bespoke log cabin service lets you tailor a cabin to your measurements, with options such as size, wall thickness, door and window positions, insulation and double glazing. Or you might simply change one of our standard designs.

Some ideas:

• Narrow plot. Choose a shallower depth and a longer front, or look at our apex roof cabins for a neat shape with good headroom.
• Big garden, big plans. Try our multi-room log cabins if you’d like a cabin with separate spaces, such as an office and a lounge.
• Open, airy feel. Our garden pavilions are fully enclosed and give a lot of light.
• Relaxing corner. A garden summer house works well for a smaller, quieter spot.
• Browse everything. Our garden log cabins range is a good place to start.

Our view: measure twice, then choose the cabin

Most people start by falling in love with a cabin, and then try to find a garden for it. We’d flip that around. Measure first, and you’ll choose with confidence.

The three numbers we’d always want to know are the narrowest usable width, the height you can build to near the boundary, and the narrowest point on the way in. With those, a cabin is easy to pick, or to adjust.

That’s what our bespoke option is for. If your garden is an awkward shape, you don’t have to settle. Send us your sketch and measurements and we’ll talk through what could work, from wall thickness to where the doors and windows sit. It’s your garden and your choice, and we’re happy to help you get it right.

Martin

Ready to turn your measurements into a cabin?

Once you have your sketch, you’re most of the way there. Take the narrowest width, the height limit and the access measurement, and look through our garden log cabins. If nothing is quite right, our bespoke log cabin service lets you change the size and layout to suit your plot. We deliver across the UK mainland, and our site also offers professional installation if you’d rather not build it yourself.

Send us your measurements and tell us what you’re hoping for. We’ll help you work out the right fit.

FAQ

How much space do I need around a log cabin?

Aim for around 60cm to 1m on every side you want to reach, so you can treat the timber and clear leaves. Add the roof overhang to your cabin size when you plan. If it’s close to a boundary, remember the 2.5-metre height limit within 2 metres.

Do I need planning permission for a garden cabin?

In England, often not, if it stays behind the front of the house, is single storey and keeps within the height limits that Which? sets out. Protected areas and listed properties have stricter rules. Check with your local council if in doubt, especially in Scotland, Wales or Northern Ireland.

How do I measure a sloping garden for a cabin?

Mark the footprint with canes, tie a level string from the highest corner to each of the others, and measure the gap from string to ground at each one. Those drops tell you how much levelling the base needs. Small drops are usually easy to deal with.

What if my garden isn’t a neat rectangle?

Use a straight baseline, such as the house wall, and measure out at right angles to the edge at regular points. Join them up on paper. Then find the narrowest usable width, because that’s the number that decides the cabin size. A bespoke cabin can be made to fit the shape.

Can I get a cabin made to my exact measurements?

Yes. Our bespoke service covers size, wall thickness, layout, doors, windows, insulation and double glazing. Send your sketch and we’ll talk through the options.

Sources

• Creating your garden plan, RHS
• Measuring and Drawing a Garden Plan, Gardening Guides
• How to measure your garden, Jo Hobbs Garden Design
• How to measure a project over areas of sloping ground, No More Digging
• Sloped garden design, Garden Ninja
• Do you need planning permission for a garden room?, Which?
• Class E, buildings etc, Planning Portal

Recommended

• How To Make The Most Of Your Garden Log Cabin
• Log Cabin Selection Wizard | Find the Right Garden Building
• Find Garden Log Cabins | Browse by Dimensions & Floor Area
• How To Build Log Cabin For Bespoke Garden Spaces

Note: This content was created using AI writing assistance and reviewed by our editorial team. Readers are encouraged to verify critical facts, professional advice, or time-sensitive information independently.