Ex-display and second-hand granny annexes: what to check before you buy
An ex-display or second-hand annexe can cost much less than a new one and be ready sooner. Only some annexes are made to be moved, though, and the saving narrows once transport, craning, groundworks and approval for your own garden are added. This page explains what to look for, what it really costs, and where to find one.
Illustrated from a scale model by The Garden Room & Annexe Guide.
In short
- What is out there: ex-display show units sold off by the companies that built them, and pre-owned annexes resold, often through the original company.
- What can be moved: annexes built as twin-unit mobile homes under the Caravan Act are designed to be moved. An annexe built on site with full planning permission is a permanent building and cannot be.
- Check the standard: an annexe someone will live in should be built to BS3632, the residential mobile home standard. Some show units are built to a holiday-home standard instead.
- Still to pay: transport and craning, foundations, groundworks and connections, and approval for your own garden. The building does not bring planning approval with it.
What “ex-display” and “second-hand” mean
Two past examples from the Guide show what each looks like in practice. Neither building is for sale now; they are here as guidance on what to expect.
Ex-display annexes are show units: buildings made for a show, an exhibition or a company’s own show site, then sold off. They are new or nearly new, and the discount reflects that they were built for display rather than to order. Heritage Living Group offered their show unit from the Great Yorkshire Show this way: a 7m × 3.6m SIP-built shell, with the cladding, roof and glazing complete and the interior left unfinished for the buyer to lay out, at £15,000 plus VAT. The buyer arranged transport from the factory and a crane at the other end.
Second-hand annexes have been lived in or used, and are resold when the owner no longer needs them. A few companies resell their own buildings and reinstall them. Booths Garden Studios have a used buildings page on their website where pre-owned studios and annexes are listed when they come back to them. One of their 2025 listings, a 20ft × 8ft annexe, was £35,000 fully installed, against £51,983 new.
Ex-display and second-hand annexes for sale
There are no ex-display or second-hand annexes to show at the moment. When an annexe company tells the Guide about a show unit or a pre-owned annexe for sale, it is listed here.
Selling one? Annexe companies with ex-display stock, and owners selling an annexe privately, can email the Guide. For a private sale, the Guide passes on interested buyers’ details and leaves the rest to the seller, with no commission.
Which annexes can be moved
Only an annexe designed to be moved can be resold to someone else’s garden.
That means one built as a twin-unit caravan under the Caravan Act: no more than two sections, assembled on site, and capable of being moved by road. Those that sit on ground screws can be lifted off them. A Room in the Garden have craned one of their own annexes to a new position, three years after building it, by preparing a new foundation and fitting steelwork around the structure for the crane straps.
An annexe built on site with full planning permission and Building Regulations is a permanent building, usually on a concrete or piled foundation. It is sold with the house, not on its own.
What to check before you buy
A second-hand annexe needs the same questions as a new one, and a few more.
- The standard it was built to. For someone to live in it, an annexe should be built to BS3632, the residential mobile home standard, or to Building Regulations. Some show units are built to BS EN 1647, the European standard for holiday homes, which is meant for seasonal use rather than year-round living. Ask for the certificate.
- Its age and condition. Look at the roof, the seals around doors and windows, and any signs of damp, and ask how and where it has been stored.
- What is included. Is there a kitchen and bathroom, or is it a shell? Does the price include transport, craning and installation?
- Size and access. Will it fit the garden, and can it get there? A two-section annexe arrives as two large pieces, usually on a lorry and then by crane, so the route from the road matters as much as the space.
- The foundation. It needs a base prepared before it arrives, usually ground screws or a slab.
- Connections. Water, drainage, power and data still have to be run from the house.
- Approval for your site. The building does not bring permission with it. On the Caravan Act route you will still need a Lawful Development Certificate for your garden, and the annexe must be used in connection with your house.
- Warranty. Ask whether any warranty transfers to you, and who will stand behind the building after installation.
What it really costs
The headline price is only part of the cost.
- Transport and craning
- These depend on the distance and the access.
- Foundations, groundworks and connections
- Typically £15,000–£20,000 for a new annexe, and broadly similar for a second-hand one.
- Approval
- The Lawful Development Certificate or planning application for your site.
- Finishing
- If it is sold as a shell, such as the Heritage show unit with its unfinished interior.
A second-hand annexe that the original company resells and reinstalls removes most of the uncertainty, because one firm is responsible for the move. Buying privately and arranging the move yourself can cost less, but the risks of transport, reinstallation and connections become yours.
Where to find them
Ex-display and second-hand annexes come up irregularly, so it pays to ask.
- Ask annexe specialists directly
- Companies with show sites replace their display buildings from time to time and sell the old ones. Booths Garden Studios list used buildings on their website when they have them.
- Visit show sites
- Walking round a finished annexe is the best way to judge the size and finish, and it is where ex-display units are most often offered. Annexe show sites lists the companies with an annexe on display.
- On the Guide
- Annexes for sale are listed in the box above when companies or owners tell the Guide about them.
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Frequently asked questions
- Can you buy an ex-display granny annexe?
- Yes. Annexe companies sometimes sell show units from exhibitions or their own show sites, usually at a discount. Check what standard the building was made to, what is included in the price, and whether transport, craning and installation are extra.
- Can a granny annexe be moved?
- An annexe built as a twin-unit mobile home under the Caravan Act is designed to be moved in no more than two sections, and can be lifted by crane onto a new foundation. An annexe built on site with full planning permission is a permanent building and cannot be moved.
- Do I need planning permission for a second-hand annexe?
- Yes. Approval belongs to the site, not the building. For a Caravan Act annexe you will need a Lawful Development Certificate for your own garden, and the annexe must be used in connection with your house. A building that does not meet the twin-unit definition needs full planning permission.
- Are second-hand granny annexes cheaper?
- Usually, but not by as much as the headline price suggests. Transport, craning, foundations, groundworks and connections still apply, and groundworks and connections alone typically cost £15,000–£20,000. A resale handled by the original company is the most straightforward.
- What standard should a granny annexe be built to?
- For someone to live in it year-round, BS3632, the residential mobile home standard, or Building Regulations for a permanent building. Some show units and holiday lodges are built to BS EN 1647, which is meant for seasonal use.
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Last updated October 2026 · Part of our garden annexe guide.
