What Is Included in a Garden Room Price?

The most misleading thing about a garden room quote is that the headline number tells you almost nothing until you know what it includes. Two companies can advertise the same size for wildly different figures, and the gap is often not margin or quality but scope: one price is for a finished, certified room you can move into, the other is for a weatherproof shell with everything else waiting as an extra. Understanding the difference is the key to comparing quotes and to budgeting honestly, because a number that looks like a bargain can become the more expensive option once the missing lines are added back in.

Shell only versus turnkey

Most quotes sit somewhere on a spectrum between two extremes. A shell-only price covers the structure: foundations in some cases, the frame, cladding, roof, doors and windows, and a weathertight envelope. Everything inside, from insulation upgrades to electrics, flooring, plastering and decoration, is then priced separately or left to you. A turnkey price, at the other end, covers the whole thing: you are handed the key to a finished, wired, decorated room ready to use. The difference between the two for the same footprint commonly runs from around five to fifteen thousand pounds, which is why a shell price and a turnkey price for the same building can look like quotes from different planets.

Neither approach is wrong. A confident DIYer who plans to fit out the interior themselves may genuinely want a shell. The danger is comparing a shell quote from one company against a turnkey quote from another and concluding the shell company is cheaper, when in reality you are pricing two different products. Even the tier-by-tier figures in a London price guide with per-square-metre rates only mean something once you have pinned down which package each quote actually represents.

The lines most often left out

When a headline price looks unusually low, the savings are almost always in the same handful of places. These are the items to check for explicitly on any quote, because their absence is what turns a tempting figure into an incomplete one.

• Foundations: on London clay this is a real engineering cost, not a token line, and it is frequently excluded from shell prices.
• Electrics: running a certified circuit from the house, with sockets, lighting and a Part P certificate, is a standard cost that budget quotes sometimes omit.
• Insulation upgrade: the difference between a summer cabin and a year-round room is thicker insulation and better airtightness, which a base price may not include.
• Internal finish: plastering, flooring, joinery and decoration turn a lined box into a usable room.
• Delivery and access: craning materials over a house or carrying them through it can be a meaningful line in the capital.
• VAT: at twenty per cent, whether it is included or added changes the picture significantly.

Where VAT hides

VAT deserves its own mention because it is the single largest add-on and the easiest to overlook. A standard domestic garden room attracts VAT at twenty per cent, and a quote that shows the figure before tax will land a fifth higher than it first appears. Always confirm whether a price is inclusive or exclusive before you compare it against another, because a VAT-exclusive quote set beside a VAT-inclusive one is not a fair comparison. Independent cost guides such as MyJobQuote's breakdown of garden room costs show how much the tax and the excluded groundwork can move a final total.

What building regulations add

Above a certain size or where the room will be slept in, building regulations approval is triggered, and that brings inspection and certification costs a smaller room avoids. Even where formal approval is not required, the electrical work is notifiable under Part P, and the government's own guidance on when you do and do not need building regulations approval is a useful check on whether a quote should include a compliance layer at all. A quote for a large or habitable room that shows no sign of building control involvement is either optimistic or incomplete.

The parts of the price you cannot see

Some of what you are paying for never appears as a physical component but matters just as much. A proper quote includes the warranty and aftercare arrangement, which is worth reading in detail rather than taking on trust. There is a real difference between a manufacturer's paper guarantee, which is only as good as the company still trading, and an insurance-backed guarantee that pays out for defects even if the original installer has closed down. The certification package is part of the price too: the electrical certificate, and where the room is large enough or habitable, the building regulations sign-off. Those documents cost the installer time and money to produce, and a quote that omits them is cheaper precisely because it is leaving you to deal with their absence later.

Design and project management are the other invisible lines. A turnkey price usually folds in the drawings, the scheduling of trades in the right order, and a single point of contact who owns the timeline. Buy a shell and coordinate the fit-out yourself and that management becomes your job, which is a hidden cost in time and stress even where it is not a cost in pounds.

How to make quotes comparable

The way to cut through all of this is to force every company to price the identical brief: the same size, the same foundation type, the same insulation standard, the same glazing, the same level of internal finish, and a clear statement of whether the figure includes VAT. Ask each for a fully itemised quote rather than a single number, so you can see the individual lines and spot where one has quietly dropped the electrics or the plastering. When the quotes are itemised to the same brief, the real differences in price and value become obvious.

It is also worth deciding how you will fund the total before you commit, because the answer can change which package makes sense. If the turnkey figure is more than you want to pay in one go, there are several ways to spread the cost of a garden room that make a fully finished build affordable without dropping down to a shell you then have to complete yourself. And if year-round comfort is the goal, paying for the insulation and U-values that make a room usable in winter is rarely the place to economise, since it is the difference between a room you use every day and one that sits empty from November. Our London cost guide sets out the wider picture behind these figures.

The bottom line

A garden room price is a description of a package, not just a number, and the only way to read one properly is to know exactly what it covers. Establish where a quote sits between shell and turnkey, confirm whether VAT is in or out, and check for the handful of lines that budget figures tend to drop. If you would like quotes that are itemised to the same brief so you can compare them line by line, share your plot size and intended use on the form on this page and we will match you with vetted London specialists who quote to a clear, comparable standard.