How Much Does a Garden Room Cost?

2026 Garden Room Price Guide by Size

The table below gives realistic price ranges for well-built, fully insulated garden rooms with electrics, foundations, and installation included. Prices reflect high-quality construction in Surrey and the South East.

These prices assume a quality build with concrete pile foundations, EPDM rubber roof, double-glazed UPVC or aluminium doors and windows, insulated walls, recessed electrics, and a plastered interior. If a company quotes substantially less, check what’s been left out.

Why Do Garden Room Costs Vary So Much?

The headline price of a garden room rarely tells the full story. Two rooms that look almost identical from the outside can differ enormously in quality and long-term durability depending on the materials used beneath the surface — the floor frame, insulation, roof membrane, and electrical spec. Here are the key reasons prices differ between companies.

Why Are Garden Rooms Expensive?

It’s worth putting the cost in perspective. For Surrey homeowners who love their current home and community but need more space, the traditional solution — moving to a larger house — easily costs over £60,000 once you factor in stamp duty, legal fees, and moving costs, before you even account for the higher purchase price. A garden room at £30,000–£37,000 delivers that extra space without the upheaval, and adds value to your existing home.

For those with a tighter budget of around £10,000, log cabins and summerhouses are an option. These are less well insulated and won’t last as long, but depending on your intended use they may be the right choice.

The 10 Key Factors That Affect the Cost of a Garden Room

1. Foundations

The foundation type has a significant impact on both price and suitability for your garden. Here’s how the main options compare:

My Retreat standard: Concrete pile foundations are included as standard in all our builds. They’re fast to install, eco-friendly, and suitable for the vast majority of Surrey gardens.

2. Electrical Connection

Always check whether the electrical connection to your home is included. Some companies provide a set length of cable; others leave you to arrange it separately. You’ll need a qualified electrician to connect your garden room to your consumer unit with a 32-amp connection. If your consumer unit doesn’t have capacity, allow around £600 for a new one. My Retreat includes 20 linear metres of electrical connection and a signed certificate as standard.

3. Internal Wall Finish

Melamine lining (PVC cladding) is quick and cost-effective but has a clinical feel. A plastered and painted finish looks like an extension of your home but costs more and takes longer due to drying times. Check whether the base coat of paint is included — new plaster is highly absorbent and can be tricky to paint over without the right primer.

4. Roof Type

My Retreat standard: EPDM rubber roof included as standard on all builds.

5. Electrics

There are two approaches: recessed electrics (wiring hidden behind plasterboard, matching standard household installation) and surface-mounted electrics (cheaper, with visible trunking channels on the walls). Recessed electrics cost more but give a far cleaner, more finished look. Standard packages typically include sockets, switches, spotlights, and an electric heater — with upgrades available for chrome or black finishes.

6. Flooring

Most companies include flooring — but check what grade. Commercial-grade laminate with a 15-year guarantee performs significantly better than entry-level alternatives. My Retreat uses Howdens commercial laminate as standard, available in a range of colours.

7. Insulation

Insulation type affects both thermal performance and cost. Here’s how the main options compare:

My Retreat standard: 50mm EPS foam insulation in floors, walls, and ceiling. Lightweight, moisture-resistant, and cost-effective. PIR is available as an upgrade in our bespoke range.

8. Wall & Floor Frame Construction

Wall frames are typically timber across the industry. My Retreat constructs wall cassettes in our UK production facility for quality control — this also means rooms can be carried through a house where there’s no side access.

9. Cladding

Cladding is one of the most visible — and most discussed — choices. Here’s an honest summary of the main options:

10. Optional Extras

Upgrades that can add cost but significantly improve the finished result:

• Roof overhang / canopy — adds shelter and kerb appeal; can be fitted on one, two, or three sides
• Wall extension — closes off the ends of a roof overhang for privacy or a distinctive design
• Composite or Millboard decking — higher upfront cost than timber but virtually maintenance-free
• Bifold or aluminium doors — aluminium is required for bifolding doors; UPVC bifolding doors in timber frames require constant adjustment
• Internal partition walls — divide the space into separate zones
• Hidden door — a storage room door clad to match the exterior for a seamless finish
• CAT6 internet connection — hardwired from your router for full broadband speed in the garden room; ideal for home offices and gyms
• Sedum / green roof — a living roof that looks spectacular and provides additional insulation

What Does a My Retreat Garden Room Include as Standard?

We believe in complete transparency, which is why our prices are displayed clearly on the website and the online design tool updates costs in real time as you add or change features. Every My Retreat garden room includes:

Is a Garden Room Cheaper Than an Extension?

Almost always, yes. A garden room avoids major structural work, party wall agreements, brickwork, and the disruption of living in a building site. For most Surrey homeowners, a garden room delivers more usable additional space for less money — and is typically completed in days rather than months. If you’re weighing up the options, our guide on whether it’s cheaper to build or buy a garden room goes into more detail.

Do Garden Rooms Add Value to Your House?

A well-built, fully insulated garden room that works year-round as a home office, gym, or studio is a genuine selling point in Surrey’s property market. Buyers increasingly seek flexible space, and a high-quality garden room is a meaningful differentiator — particularly at the price points common in the South East.

Frequently Asked Questions