An outdoor sauna with glass on two sides, a teak deck underneath and a plan for the monsoon

What outdoors asks of a cabin in the tropics

1. Water from above and from the side. A flat roof with a proper fall and a drip edge, a sealed junction with the glass frames, and a deck that drains away from the cabin walls instead of toward them.
2. Termites and rot from below. The cabin stands on a ventilated, raised base of steel, concrete or treated timber clear of the ground, with stone or stainless feet where it meets soil.
3. Sun on glass. Two walls of glass in the afternoon sun need double glazing with a solar-control coating, or a roof overhang that shades them. See glass saunas in the tropics.
4. Lightning and surges. An outdoor cabin has a cable run and a metal frame, so the circuit gets its own breaker, an RCD and surge protection, with the earthing done to the electrician's drawing.

The deck is half the build

A cabin set on bare lawn looks like a storage shed and behaves like one. On a landscaped teak deck with planting, a few lit steps and a clear route to the pool or the house, it becomes part of the garden. We draw the deck, the steps, the landscape lights and the cable route at once. A deck extra covers the boards and frame; the paving, planting and any retaining wall belong to your landscape contractor.

Seats, power and baht

Heaters from about 8 kW are normally wired three-phase, which many gardens reach only through a new cable from the house or a new supply request to the utility. Ask early; it is the item most likely to set the schedule. Sauna power in Thailand lists the questions.

Deck dimensions that work

Around a cabin the deck wants a clear apron of about 1.2 m at the door and steps wide enough for two people with towels. A 4-seat cabin of 2.0 x 1.7 m inside therefore sits on a deck of roughly 3.6 x 3.2 m, with a 6-seat cabin on about 4.0 x 3.6 m. Add the walkway to the pool, the plant niche and the cable route to the plan before the deck is priced; that is where decks grow.

Siting: sun, neighbours, and where the cold pool goes

• Glass faces the view, solid wall faces the neighbour. Two glass walls at a corner give the view; the blind side takes a teak slat screen for privacy.
• Pool within ten steps. The cold plunge pool or tub belongs near the door, shaded by the cabin's own roof edge or a pergola; see cold plunge pools.
• Cable and water routes marked first. A 20 m trench to a distribution board costs more than the cabin's extras.

Permission: questions for the local office

Whether a small free-standing cabin counts as a building needing a permit depends on its size, height, distance from the boundary and the local authority; we do not guess. Ask your municipality, tambon administrative office or, in Bangkok, the district office. The Phuket note lists what to take with you.