A garden room gives you a dedicated space for a home office, gym, studio or guest room, without the cost and upheaval of extending the house itself. Because every garden is different, and because the specification can range from a simple insulated box to a fully finished room with heating, plumbing and high-end glazing, costs vary considerably. As FMB-registered builders with over 20 years of experience across Solihull and the West Midlands, this guide sets out what drives the cost of a garden room and what to expect at each stage.
What affects the cost of a garden room?
A number of factors determine what you will pay for a garden room:
- Size — a small garden office will cost considerably less than a larger garden room designed as a gym, studio or guest annexe.
- Foundations — ground conditions affect whether a simple screw-pile or concrete pad foundation is suitable, or whether more substantial groundwork is needed.
- Insulation specification — a garden room intended for year-round use needs a higher level of insulation in the walls, roof and floor than one used only occasionally, which affects both comfort and running costs.
- Glazing — the amount and quality of windows and doors, including bi-fold or sliding doors, has a noticeable effect on cost and on how light the finished room feels.
- Electrics and heating — sockets, lighting, data points and heating all add to the cost, and are worth specifying properly from the outset if you plan to use the room as a proper working or living space.
- Plumbing — a garden room with a kitchenette or shower room costs more than one without, due to the additional drainage and water supply work involved.
- Access and site conditions — a garden that is difficult to access, or a long distance from the house for services, can add to the cost of the groundwork and connections.
Typical garden room cost ranges
Because garden rooms vary so much in size, specification and intended use, we deliberately do not quote a single fixed price per square metre here. A modest, well-insulated garden office with basic electrics sits at the lower end of the cost scale, while a larger garden room designed as a gym or studio, with higher specification glazing, underfloor heating and a premium finish, sits at the higher end. A garden room with a kitchenette or shower room, requiring plumbing and drainage, will cost more again due to the additional services involved. The most accurate way to budget for your project is a free, no-obligation site visit, where we can assess your garden, discuss your intended use, and give you a clear, itemised quote.
Garden room cost compared to a house extension
A garden room is generally a lower-cost option than a comparable-sized house extension, because it is a smaller, standalone structure that does not need to tie into your existing house structure, roofline or services in the same way. If you are deciding between the two, our guide to garden room vs house extension compares cost, planning permission and timescale in detail, to help you work out which suits your situation.
Do you need planning permission for a garden room?
Most garden rooms in Solihull can be built without planning permission, as they fall under permitted development rights for outbuildings, provided they are single storey, sit behind the front of the house, and keep within set height and coverage limits. Garden rooms within 2 metres of a boundary are limited to 2.5 metres in height, rising to 4 metres further from the boundary with a dual-pitched roof. All outbuildings combined also cannot cover more than 50% of your garden. Our full guide to garden room planning permission sets out the rules in detail, including when full planning permission is more likely to be needed, such as in conservation areas or on properties where permitted development rights have been removed.
Do garden rooms need building regulations?
Separately from planning permission, building regulations can still apply depending on size and use. A garden room under 15 square metres with no sleeping accommodation is generally exempt from building regulations. Between 15 and 30 square metres, it can still be exempt provided it has no sleeping accommodation and is either at least 1 metre from a boundary or built from substantially non-combustible materials. Larger garden rooms, or any used for sleeping accommodation, will usually need full building regulations approval, which we manage on your behalf as part of the build.
How long does a garden room take to build?
Garden rooms are generally quicker to build than a house extension, due to their smaller scale and simpler foundations, with work happening away from your existing house rather than tying into it. Exact timescales depend on the size and specification of the room, including how much glazing, electrics and any plumbing is involved, but disruption to your day-to-day home life is typically far lower than with an extension, since the build site is separate from where you live. We agree a realistic programme with you before work starts.
Getting an accurate quote
Because garden room costs vary so much with size and specification, the best way to budget properly is a proper, itemised quote based on your own garden and requirements, rather than a generic price per square metre. Our guide on how to choose a builder in Solihull covers what a good quote should include and the questions worth asking before you commit to any builder.
About HK Builders
HK Builders Ltd is an FMB-registered, fully insured, family-run building company based in Solihull, with over 20 years of experience building garden rooms and extensions across Solihull and the West Midlands, including Dorridge, Knowle, Shirley, Sutton Coldfield, Harborne, Moseley, Coventry and Redditch. As our reviews show, clients value our clear, itemised quotes and the way we manage planning and building regulations on their behalf. Explore our garden rooms page for the full range of what we build, or get in touch for a free, no obligation quote.
Call 07393 194 336Get a free quote
Frequently asked questions
How much does a garden room cost in Solihull?
Is a garden room cheaper than a house extension?
Do I need planning permission for a garden room in Solihull?
What is included in a garden room quote?
Guides worth reading
Guides from the HK Builders blog on garden rooms, costs and planning permission.
