Do You Need Building Regulations for a Conservatory?
Updated: 9 hours ago
You do not need building regulations approval for a conservatory in England if it meets all five exemption conditions: it is no more than 30 square metres, built at ground level, separated from the house by external-quality doors, has its own heating with independent controls, and its glazing meets safety standards. Miss any one of those and the conservatory is treated as an extension, and building regulations apply in full.
These rules apply in England; Wales and Scotland have their own building regulations, and the details differ.
What are the building regulations exemption conditions for a conservatory?
To qualify, a conservatory must meet every one of these.
Floor area of no more than 30 square metres, measured internally.
Built at ground level, single storey.
Separated from the house by external-quality walls, doors or windows, so that the thermal envelope of the house is unbroken.
Heating, if any, on its own independent temperature and on/off controls, not simply an extension of the house system.
Glazing that complies with the safety glazing requirements in critical locations (doors, glass beside doors and glass below 800mm from the floor), and any new electrical circuit carried out by a registered electrician or notified. These apply to all building work, exempt or not.
The conservatory must also have a translucent roof and walls that are substantially glazed. A solid-roofed room with brick walls is an extension whatever it is called.
What takes a conservatory out of the exemption?
Opening it up to the house. The moment the doors between house and conservatory are removed, or replaced with an opening, the conservatory becomes part of the heated envelope of the home, and the regulations for extensions apply to its insulation, glazing and structure.
Heating is the second trigger. Running the house radiators into the conservatory on the same thermostat, with no way to turn the conservatory off separately, breaks the exemption even if the doors remain. A solid-fuel stove is treated separately: a log burner in a conservatory must meet Part J whether or not the room itself is exempt.
Size is the third. A conservatory of more than 30 square metres needs approval regardless of the rest. A solid roof is the fourth, because the exemption depends on a translucent roof.
Building open to the house is the usual choice for a kitchen extension; it simply means designing and approving the room as an extension from the start. Our luxury conservatories are specified either way; the decision is made with the drawings, not discovered at the end.
Do you need building regs for a conservatory if planning permission is not needed?
The two are separate: planning is about whether you may build, building regulations about how it is built. Many conservatories that fall within permitted development still need approval because they open to the house. Our guide to whether you need planning permission for a conservatory covers the planning side, and the Planning Portal sets out the current position on each.
What does building control check on a conservatory?
The foundations and base first: depth, bearing and the damp-proof course. Then the structure, including any steel or beam where the house wall has been opened, with structural calculations to support it. Then thermal performance: the insulation in the floor and any solid roof or wall areas, and the glazing's U-values. Safety glazing in doors, side panels and low-level glass. Drainage from the roof and any new foul or surface water connections. Electrics, either certified by a registered electrician or inspected.
How do you get building regulations approval for a conservatory?
Either a building notice, which is quicker and suits straightforward work, or a full plans application, which is checked in advance and suits anything with structural or thermal complexity. As a guide to fees:
Building notice: typically several hundred pounds, depending on the council and the size of the work.
Full plans application: over £1,500 for larger or more complex projects.
Structural calculations: about £300 each, where needed.
On completion the local authority or a registered building control approver (formerly an approved inspector) issues a completion certificate, which is the document your solicitor will ask for when you sell.
Where the conservatory is exempt there is nothing to submit, but keep the drawings and glazing specification as evidence.
Building regulations for a conservatory questions, answered
Do you need building regulations for a conservatory with a solid roof?
Yes. A translucent roof is one of the conditions of the exemption, so a new conservatory with a solid roof is an extension for building regulations. The same applies when you replace the glass or polycarbonate roof of an existing conservatory with a solid or tiled one: it generally needs approval, and building control will check that the frames, base and foundations can carry the extra weight, usually via a ring beam, and that the roof meets insulation standards.
What happens if you build a conservatory without building regulations when they were needed?
The local authority can require the work to be opened up, altered or removed, and the absence of a completion certificate becomes a problem at sale. A regularisation application after the fact is possible but is more expensive than doing it properly.
Is an orangery exempt from building regulations?
Rarely. Its solid roof and usual opening to the house fail the exemption. Our guide to orangery building regulations explains the detail.
Talk to our design team
Building regulations are a standard, not an obstacle, and a conservatory that meets them is a better room for it. If you are planning one that opens to the house, talk to us about your project and we will design the approval in from the start.
