How Much Does a Garden Room Cost in 2026?

If you’re considering a garden room in Rainford or St Helens, whether it’s a home office, gym or extra living space, cost is the first thing most people want to know. Here’s what garden rooms typically cost in 2026, what affects the price, and a real example from a job we’ve completed locally.
UK Average Cost of a Garden Room
The average cost of a garden room in the UK is around £20,000 to £38,000 for a room of 12 to 15 square metres, depending on size, specification and whether you need plumbing for a bathroom or kitchenette.
For a straightforward, well-insulated garden room without plumbing, you’re typically looking at £1,700 to £2,000 per square metre. Add a shower room or kitchen area and costs rise to around £2,200 per square metre or more, because of the extra plumbing, drainage and waterproofing involved.
What Affects the Price
- Overall size of the room and its footprint
- Whether you need an en-suite or kitchenette, which means plumbing and drainage
- Glazing, such as bifold or French doors and window layout
- Insulation and cladding specification
- Electrics, lighting and heating, including how many sockets and light points you need
A Real Garden Room Cost from Rainford Buildings
We recently completed a 3.4m x 6m garden room in Rainford, built as a split teen room with a full en-suite (toilet, sink and shower). The total cost, including VAT, was £34,440. This was a high end spec with UPVC cladding so low to no maintenance and dug out and buried services back to the main house.
That works out at roughly £1,680 per square metre including VAT, which is competitive for a room of this specification once you factor in the en-suite. A comparable room without plumbing would cost noticeably less.
What’s Typically Included
- Timber-framed construction with a fully insulated floor on a damp-proof membrane
- Structural cladding, finished to your chosen style
- Fully adhered rubber roofing membrane
- UPVC French doors and windows
- Full electrics, including sockets, switches, LED ceiling lights and external lighting
- Laminate flooring throughout
- A wall-mounted electric panel heater
- En-suite facilities with a macerator pump for waste, where included
Getting an Accurate Quote
Every garden room is different, and the figures above are a guide rather than a fixed price. The best way to get an accurate cost is a site visit, where we can look at the space, talk through what you want the room to do, and give you a firm quote. Get in touch with Rainford Buildings to arrange yours.


