The short answer
To get a meaningful garden room quote, tell builders your intended use, the size you want, your garden’s access and ground conditions, and your glazing and insulation expectations. Always get at least three itemised, supplied-and-fitted quotes from garden room builders and ask each to quote the same specification. See the cost guide to understand what each element should cost.
Getting garden room quotes is easy to do badly — accepting the first price you are given, comparing quotes that cover different specifications, or choosing the cheapest without checking whether it includes the base, insulation, glazing and electrics a proper installation requires. This guide walks through how to prepare a proper quote request, what to expect from a good builder’s response, and how to compare proposals on a like-for-like basis.
Getting quotes at a glance
- Minimum quotes Three (ideally four)
- From Established garden room builders
- Quote format Itemised, in writing
- What to provide Use, size, access, ground, glazing
- Site visit Request one — avoid online-only prices
- Comparison method Same size; same spec; check base & insulation
What information to give builders when requesting quotes
The more information you provide upfront, the more accurate and comparable your quotes will be. At a minimum, tell each builder:
- Intended use: office, gym, studio, hobby room or guest space — this affects insulation, power and whether planning is straightforward.
- Size you want: approximate footprint, or the floor area you are working toward. Bear in mind the permitted development size limits.
- Garden access and ground: how materials will reach the spot, whether the ground is level, and any known issues like a slope, soft ground or tree roots. This drives the base specification.
- Glazing and finish expectations: bi-fold or sliding doors, the amount of glazing, and the exterior cladding you have in mind.
- Services: whether you want electrics only, or also plumbing for a toilet or kitchenette — the latter has planning and Building Regulations implications.
Ideally, invite the builder for a brief site visit rather than quoting from photos. A site visit takes 30–45 minutes and lets the builder assess access, ground conditions and boundary distances, and give you a far more accurate price. Online-only estimates are faster but lead to more surprises once work starts.
What a good quote looks like
A properly itemised quote should set out: the floor area and external dimensions; the base or foundation type; the wall, floor and roof insulation specification; the glazing and door specification; the exterior cladding and roof covering; the internal finish; the electrical fit-out and its connection to your house; and the warranty. If groundworks beyond a standard base are needed, they should be quoted separately with a reason. If insulation values or glazing are vague, ask for them to be stated precisely — these are the items that determine whether the room is usable year-round. Any “provisional sums” for unforeseen groundworks should be flagged, so you understand the conditions that would trigger additional charges.
| Item | Should be in the quote? |
|---|---|
| Floor area and external dimensions | Yes — specified exactly |
| Base / foundation type | Yes |
| Insulation spec (floor, walls, roof) | Yes — values stated |
| Glazing and doors | Yes — type and specification |
| Cladding and roof covering | Yes |
| Electrical fit-out (Part P) | Yes — included, not extra |
| Internal finish | Yes |
| Warranty details | Yes — years and conditions |
How to compare quotes fairly
Once you have three quotes in hand, line them up item by item. A price difference may be entirely explained by what is included: one builder at £18,000 may include a higher insulation specification, bi-fold doors and a 10-year structural warranty; another at £16,500 may use thinner insulation, a single door and a shorter warranty. Adjust the prices to a comparable basis by accounting for the specification differences. Then consider the less-quantifiable factors: references, examples of completed rooms, communication, and whether the builder carried out a site visit. The right choice is rarely the cheapest on paper if that cheapest quote is built to a lower specification. See our guide to mistakes to avoid for the traps to watch. This is general information; actual costs and scope vary with your garden and chosen builder.
When to use a quote comparison service
Quote comparison services can save time by gathering multiple quotes from local garden room builders simultaneously. When using one, ensure the service passes your request to builders who will carry out a proper site visit rather than generating an automated online price. The most useful service connects you to real local builders who assess your garden in person — that is closer to getting three independent quotes than an instant online calculator. Always satisfy yourself independently about each builder’s track record and contract terms, regardless of what the platform says about vetting. This page is general information; quotes are estimates and the actual cost depends on your specific garden, ground conditions and chosen builder.
Compare garden room quotes now
Use our service to compare itemised, supplied-and-fitted quotes from garden room builders in your area. Free to use, no obligation.
Frequently asked questions
How many garden room quotes should I get?
At least three. This gives you a realistic price range, helps you spot outliers in either direction, and is the most reliable way to confirm you are paying a fair market rate for a properly specified room.
What should I tell builders when requesting a garden room quote?
Give your intended use, the approximate size, your garden’s access and ground conditions, your glazing and insulation expectations, and whether you want any plumbing. A site visit is far more accurate than an online estimate.
Is the cheapest garden room quote always the worst?
Not always, but the cheapest quote is often cheapest because it is built to a lower specification — thinner insulation, a lighter base, or a shorter warranty. Itemise and compare the specification before deciding, rather than choosing on headline price alone.
How long does it take to get a garden room quote?
An online request typically generates responses within 24–48 hours. A site visit can usually be arranged within a week, and most builders aim to quote within a few days of visiting. Allow a couple of weeks for the comparison process if you are not in a hurry — rushing produces worse outcomes.
Sources & further reading
- GOV.UK Planning Portal — outbuildings, permitted development and when planning permission is needed
- GOV.UK / Building Regulations Approved Documents (Part L, Part P) — energy efficiency and electrical safety
- Trade and industry guidance — what a complete supplied-and-fitted garden room quote should include
- Your Local Planning Authority — local rules, conservation areas and confirmation for your property
This is general information, not advice for your specific property or project. Costs, timescales and outcomes vary with your garden, ground conditions and chosen builder. Planning rules vary locally and permitted development can be removed by an Article 4 direction — always confirm with your Local Planning Authority.