How to Compare Garden Room Quotes

Two quotes for the same size room can be £10,000 apart and still not be comparable. Here is how to tell what you are actually being offered.

By Kieron Summerhayes, My Retreat Garden Rooms · Updated October 2026

Most people get three or four quotes for a garden room, then struggle to compare garden room quotes that are laid out in completely different ways. One includes foundations, another adds them later. One plasters the walls, another lines them with boards. The headline price tells you very little until you know what sits behind it.

Why Garden Room Quotes Are So Hard to Compare

There is no standard specification for a garden room. Some companies quote a shell and price everything else as extras. Others quote a finished room you can move into. A low quote is often low because something is missing, not because it is better value. The questions below are the ones that most often explain the gap.

The 10 Questions to Ask

1. What foundation is included?

Foundations can add £500 to £5,000 or more depending on the type and the ground. Ask which foundation is in the price, how deep it goes, and whether it changes after a site visit. Be wary of plastic grids or paving slabs for a fully insulated room. They suit sheds, not permanent buildings.

At My Retreat: concrete piles are included as standard in every price. After the site visit we may recommend ground screws, or a concrete pad for heavier uses such as gyms, depending on your ground and how you will use the room. Compare garden room bases.

2. What is the floor frame made of?

The floor frame sits closest to ground moisture, so it is where cheaper rooms fail first. Ask whether it is timber or steel, and if timber, how it is treated and kept off the ground.

At My Retreat: a structural steel floor frame as standard. It will not rot, warp or move. A weed membrane goes down first, and the frame sits with a small air gap above the ground so air can flow underneath.

3. How much insulation, and where?

Ask for the insulation type and thickness in the floor, walls and ceiling separately. A room insulated in the walls but not the floor will be cold underfoot all winter.

At My Retreat: 50mm rigid EPS insulation in the floor, walls and ceiling as standard, and 75mm on bespoke builds over 30m².

4. What are the walls made of, and how are they finished inside?

Ask what sits between the cladding and the inside wall, not just how it looks. Plastered walls, plasterboard with taped joints, and timber or MDF lining all look and feel very different. Ask exactly what you will see on handover day, whether it is painted, and whether you can fix a TV or shelves straight to the wall.

At My Retreat: every wall includes a sheet of OSB on the inside face. It keeps the sections square in transit, and adds strength and warmth, so you can fix TV brackets straight to the wall. That is covered with plasterboard and skimmed, ready for decorating. A mist coat can be added if you want it.

5. What does the electrical allowance cover?

Ask whether the connection to your house is included, or whether you are expected to have power at the room already. Then ask how many sockets and lights are included, whether there is a separate consumer unit, how far the cable run from the house is allowed for, and whether you receive an electrical certificate at the end.

At My Retreat: the connection to your house is included, with a cable run of up to 20 metres, plus a dedicated consumer unit, lighting circuit and recessed spotlights. You can pick an electrical package in the configurator to see the overall cost, then at the survey we go through every option so you choose exactly the electrics you want. The work is carried out by qualified electricians and you receive an electrical certificate on completion.

6. Are heating and flooring included?

These are the two items most often left out of a headline price. A room with no heater or bare boards is not ready to use.

At My Retreat: a 2kW smart Wi-Fi panel heater and Howdens Professional V Groove laminate flooring, fitted with white MDF skirting, are both included.

7. What happens if the ground or access is difficult?

Slopes, tree roots, poor soil and tight side access can all add cost. Ask when you will find out, and whether the price can change after you have signed.

At My Retreat: we check ground conditions, access and power at the free site visit and confirm anything outside the standard allowance before you commit.

8. Who manages the build?

Ask who your point of contact is from design to handover, and who coordinates the different trades. A room built by several trades with nobody in charge is where delays and snagging come from.

At My Retreat: Kieron manages every project personally from design to handover, coordinating a small team of trusted specialist trades.

9. How is it made, and how long will it take on site?

Ask whether the room is built from scratch in your garden or made in sections off site. Ask how long the build takes once work starts, not just the lead time to the start date, and when the room will be watertight.

At My Retreat: we make the bespoke sections in the factory under controlled conditions, which gives a better product. It also makes the install quicker and cleaner, with less waste and without lots of deliveries and raw materials arriving at your house. The room is usually up and watertight by the end of the first week, and the full build takes around 2 weeks on site on average: from 6 working days for a small room up to 15 working days for a large one.

10. What does the guarantee actually cover?

A “10-year guarantee” can mean very different things. Ask which parts are covered, for how long, and whether doors, windows, roof and electrics are covered separately.

At My Retreat: a 10-year structural guarantee on the steel floor frame, structural framework and roof structure, with the full terms on our terms and conditions page.

Questions That Are Not About Price

A few checks protect you whichever company you choose:

• Reviews: read recent reviews on more than one platform, and look for reviews that name the person you will be dealing with.
• Finished rooms: ask to see photos of recent builds, or whether you can visit a finished room.
• Payment terms: ask how payments are staged and what you pay before work starts.
• Planning and building regulations: a good builder will tell you what needs checking for your property, such as height near boundaries, rooms over 30m², or conservation areas. Confirming the position for your own property is the homeowner’s responsibility, so check with your local planning authority or an architect before going ahead.