Planning, process & cost
How a garden room is built, from base to finish
The parts you can't see afterwards are the parts that decide if it's usable in January.
The difference between a garden room you use all year and a shed with plasterboard is almost entirely in the build-up: the base, the insulation, the way moisture is managed in the wall, and how services arrive. Any of these done poorly produce the same symptoms — cold in winter, condensation on the inside of the glazing, and a room that quietly turns into storage.
The base
Concrete slab, ground screws or a bearer-and-pad system all work; what matters is that it is level, adequately supported for the ground conditions, and keeps the timber structure clear of the ground with airflow beneath.
Frame and insulation
A timber frame with insulation between and, ideally, a continuous layer to reduce cold bridging through the studs. Floor and roof need insulating as seriously as the walls — heat loss through an uninsulated roof deck is what makes a garden room expensive to warm.
Managing moisture
A garden room used as an office generates moisture from people and heating. The wall build-up needs to control where that moisture goes — a vapour control layer on the warm side and a breather membrane and ventilated cavity on the outside. Getting this wrong causes interstitial condensation you cannot see until damage appears.
Services and glazing
Power needs a correctly specified and installed supply from the house. Glazing position affects both light and heat — large south-facing glazing without shading overheats in summer as reliably as it is pleasant in spring.
Planning and Building Regulations
Many garden rooms fall under permitted development, subject to size, height, position relative to boundaries and how the building is used. Sleeping accommodation and certain sizes change the position. Always confirm the current rules for your property and use before building — the local planning authority is the source of truth.
Questions we're asked about this
Thinking about a garden room?
Tell us the intended use, the space available and the ground conditions and we'll advise on the build-up before anything is ordered.
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