We don't publish fixed prices because every garden is different. Your written quote will state what's included — and what isn't, such as planning fees, furniture or work to the main house.
The main cost factors
Size and layout
The footprint and internal height have the biggest effect. A second room or partition adds materials and labour.
Glazing
Large sliding or bi-fold doors and extra windows cost more than standard doors, but change how the room feels.
Cladding and roof
Timber, composite and other cladding finishes vary in price and maintenance; roof style affects height limits too.
Foundations and ground
Sloping gardens, soft ground or tree roots can mean more preparation before the build starts.
Services
Power, lighting, data and heating are common. Water and drainage for a toilet or shower add more.
Access
If materials have to be carried through the house or a long path, installation takes longer.
Approvals
If planning permission or building regulations approval is needed, fees and design work are extra.
Checklist for your quote
- Size and footprint of the room
- Glazing type and amount
- Cladding and roof finish
- Foundations, ground conditions and garden slope
- Electrics, data and heating
- Plumbing and drainage (if adding a toilet or shower)
- Site access for materials
- Planning or building regulations requirements
See our prices page, the planning guide, or find your town.