Thinking about a garden sauna? Here's what to plan first

A garden sauna used to be something you saw on Scandinavian holiday programmes. Now they are turning up at the bottom of British gardens, next to the shed and the vegetable beds. If you are thinking about one, the sauna is the easy part. The work is in choosing where it goes and getting the ground and the power ready for it.
Here is what to think about before you buy.

Choose the spot first

Start with the walk from the back door. You will use the sauna most in autumn and winter, often in the dark, so a short, lit, level path matters more than a long view. Thirty steps across a wet lawn in a towel gets old quickly.

Then think about the space around it. Leave at least a metre of clear ground on every side. You need that room to build the sauna, and later to treat the timber and get round the back. Keep it away from overhanging trees too. Leaves and sap on the roof are a chore, and a falling branch is worse.

Privacy is the last part. Most people want to sit outside between rounds and cool down, so a spot screened by a hedge or fence makes the sauna far more pleasant to use.

Get the base right

A sauna is heavy and has to sit level, or the doors and benches will never line up. The usual options are:

• a concrete pad, which is the most solid choice and suits larger cabins

• paving slabs laid on a compacted sub-base, which is fine for most models if the slabs are level and well bedded

• a timber deck with proper footings, if it is built to take the weight

Whatever you choose, make it a little larger than the sauna's footprint and give it a slight fall so rainwater runs away from the timber. Grass or loose gravel on its own is not enough.

Power, or fire

Most garden saunas run on an electric heater. A typical one is between 6 and 9 kW, which needs its own circuit from your consumer unit, run by a qualified electrician. Budget for the cable run from the house, and plan the route before the base goes down so the armoured cable can go in at the same time.

The other route is a wood-burning stove. It needs no electrics at all, which helps if the sauna is a long way from the house. It takes longer to heat and you have to feed it, but plenty of owners say that is the point. Check the stove is approved for the sauna you are buying, and keep a sensible distance from fences and neighbours' windows for the flue.

Do you need planning permission?

In England most garden saunas count as outbuildings under permitted development, so they do not need planning permission if they stay within the limits. The main ones are:

• no taller than 2.5 metres if it sits within 2 metres of a boundary

• not in front of the house

• buildings, sheds and extensions together cover no more than half the garden

Different rules apply in conservation areas, to listed buildings, and in Scotland, Wales and Northern Ireland. If in doubt, ask your council before you order. A short email now is cheaper than moving a sauna later.

Picking a shape

Outdoor saunas come in three broad styles, and the right one depends on your garden as much as your taste.

Barrel saunas. These are the classic curved shape. The round profile sheds rain well and heats evenly, and it suits informal or cottage gardens.

Cube saunas. These have flat sides and a modern, boxy profile, often with a large glass front. They sit well next to contemporary houses and garden rooms.

Cabin saunas. These look more like a small garden building, with a pitched or flat roof and sometimes a covered porch. They are a good choice if you want the sauna to blend in with a shed or summerhouse.

Size matters more than people expect. A two person sauna heats faster and costs less to run. A larger cabin is worth it only if you will regularly fill it. If you want to compare shapes and sizes side by side, the range of outdoor saunas from Hekla covers barrel, cube and cabin designs, with electric and wood-fired options.

Building it

Most garden saunas arrive as a kit of pre-cut timber panels. A confident DIYer with a helper can usually build one over a weekend once the base is ready. If you would rather not, many retailers will send a team to build it for you, so ask when you buy.

Looking after it

Timber outdoors needs a little care. Treat the outside with a breathable exterior wood finish every year or two, brush leaves off the roof, and check the roof covering after winter storms. Inside, leave the wood untreated, wipe the benches after use, and leave the door open for a while afterwards so the cabin dries out.

The short version

Pick a spot that is close, private and clear of trees. Put the sauna on a level, solid base. Sort the power or the flue early, and check the planning rules before you order. Get those right and the sauna itself is the straightforward bit.