A guide to the two exemptions a conservatory can use, the conditions that keep them in place, what changes when the roof is replaced with a solid one, and how to confirm the route with your council.
A conservatory is one of the few additions that Building Regulations treat more lightly than the rest. A kitchen extension needs approval from the first brick. A conservatory built to the right conditions does not. That exemption is real, and it is also easy to lose, which is why it is worth checking before a conservatory roof is replaced.
The exemption has two parts. One sits in the Building Regulations 2010 themselves, in Schedule 2. The other sits in Approved Document L, which deals with fuel and power, in paragraph 0.14. Each has its own list of conditions, and the conditions are about the whole conservatory and not just the roof. Change the building around the roof and the exemption may go with it.
This guide takes the conditions one at a time, then looks at what happens when a polycarbonate or glass roof is swapped for a solid one, and which council to call in East Kent. It applies to conservatories attached to houses in Margate, Ramsgate, Canterbury, Dover and nearby villages, and it sits within our conservatory roofs work.
Why a conservatory roof meets the Regulations at all
Building Regulations apply to building work: new buildings, extensions, and certain alterations to existing ones. A conservatory attached to a house is an extension, so in principle it is caught like any other. Schedule 2 of the Building Regulations 2010 lists classes of work that are exempt, and a conservatory can fall into one of them.
That is the first thing to understand: exempt does not mean ignored. It means the work does not need a building control application. The conservatory still has to be safe and sound, and anything that sits outside the exemption still needs the right approval.
The roof is where this matters most, because a conservatory roof does three jobs. It keeps the weather out, it carries its own weight along with wind and snow, and it governs how warm the room feels. Once the roof is replaced, the question becomes whether the new roof still sits inside the exemption or turns the room into a different kind of space.
The Planning Portal's guidance on roof changes starts from what homeowners actually do: swap a traditional polycarbonate roof for a solid tiled one, hoping to keep more heat in. Its answer is that the new roof has to meet the Regulations on structure, energy performance and ventilation. The sections below show how the exemptions and that answer fit together, and where the line falls for a roof you are planning.
Schedule 2, Class 7: ground level, not over 30m2
Class 7 of Schedule 2 covers adding a conservatory or porch to an existing building. Its conditions, in plain words:
- the addition stands at ground level
- the floor area stays within 30m2
- the glazing meets the requirements of Part K of the Regulations
The floor area is the conservatory's own, and the 30m2 limit is a hard line: a conservatory of 31m2 falls outside the class. If you are unsure of the figure, measure the internal floor from wall face to wall face and write it down, because every later question starts with that number.
The Part K condition is about glazing safety. Glass in a conservatory is often low and close to doors, where someone can fall against it, so Part K asks for safe glazing in the places where that matters.
Class 7 is an exemption from the need for approval, and it holds only while each of its conditions is met. Whether an extension counts as a conservatory in law, or as a glazed room with a solid roof, depends on how it is built, so a drawing and a survey come before any assumption.
The detailed wording sits in Schedule 2 of the Building Regulations 2010 on legislation.gov.uk, and your council's building control team will confirm how it reads for your site. Ask before the order for the new roof is placed, since the answer can change the specification.
Approved Document L, paragraph 0.14: the energy exemption
A separate set of conditions covers the energy rules. Approved Document L, paragraph 0.14, lets a conservatory or porch stand outside the energy efficiency requirements if it meets its conditions. They describe how the conservatory relates to the house.
| Condition | What it asks |
|---|---|
| Level | The extension is at ground level. |
| Size | Floor area not over 30m2. |
| Separation | Wall, door or window between house and conservatory retained or replaced. |
| Heating | The house heating is not extended into it. |
The separation condition is an easy one to lose. If the wall between the house and the conservatory is knocked through, the conservatory is no longer a separate space, and the exemption goes. Where the old external doors stay in place and are closed, it holds.
The heating condition works the same way. A radiator on the house's central heating system in the conservatory extends the heating into it. The rule is worded around the dwelling's heating system, so ask your council before you rely on any other heater.
Where the conservatory stays inside these conditions, the energy requirements do not apply to it. Our guide to the conservatory exemption goes through each condition again, and our page on heating a conservatory deals with the heating rule in more depth.
Keep those four conditions in mind when a quote arrives. A roof job that also removes the door or adds a radiator should be put to the council before it starts, because the extra work changes the answer for the whole conservatory.
How the exemption is lost
Think of the exemption as a list of things you must not do. Most ways of losing it are changes made when someone wants the conservatory to work as part of the house.
The common ones:
- The wall, door or window between the house and the conservatory is removed, and the rooms open into each other.
- The house central heating is extended into the conservatory with a radiator or underfloor loop.
- The floor area is increased beyond 30m2, for example by a later addition at the side.
- A raised floor or an upper level is added, so the room is no longer at ground level.
- The glazing is changed to something that no longer meets Part K.
None of those relates to the roof itself, but the roof job is often when they come up. A homeowner who wants a warm room all year may order a solid roof, remove the door and fit a radiator in one project. Each step looks small, and together they take the conservatory out of the exemption and into the full Regulations.
On its own building control page, Dover District Council describes some conservatories and porches as exempt, if they are cut off from the house by doors and left unheated. That description applies to Dover District addresses. It echoes the separation and heating conditions above, and shows that each council puts the exemption in its own words.
The 2026 edition of Approved Document L takes effect on 24 March 2027 for use in England, for building work that is not in connection with higher-risk building work.
Replacing the roof with a solid one
A solid roof replaces glass or polycarbonate with a tiled or insulated panel system. HomeBuilding gives a typical lifespan for a polycarbonate conservatory roof of 10 years. The Eco Experts, in an April 2024 page, say about 10 to 15 years. Those are typical ranges, not promises.
The Planning Portal's position is that a replacement roof has to meet the Regulations, so that it is structurally sound, energy efficient and ventilated. A solid roof is much heavier than polycarbonate, so the walls, frame and foundations are checked for the extra load.
The questions that approval answers:
- Can the existing frame, walls and foundations carry the weight?
- What insulation does the roof need, and how is it ventilated?
- Does the new roof meet the energy and ventilation requirements the Planning Portal names?
- Are the flashings and the junction with the house wall detailed properly?
MyJobQuote gives a typical UK range for a conservatory roof replacement of £3,200 to £6,000, and The Eco Experts £2,300 to £6,000, in its April 2024 page. A written price for your conservatory follows a survey, and it states whether building control is part of the job.
Whether planning permission is needed is a separate matter from the Regulations. Our guide to planning for a solid conservatory roof covers it, and listed buildings and conservation areas add further consent routes that sit alongside the Building Regulations and need their own answers.
Which council to ask in East Kent
Who deals with building control differs between East Kent districts, so the first step is to find the right one for the address.
Thanet District Council runs its own building control team, on 01843 577522. Folkestone & Hythe District Council also runs its own, on 01303 853538. Dover District Council keeps its building control service in house as well, and its details are on the council's website.
Canterbury and Swale both use STG Building Control, on 01634 331133. A conservatory at an Ashford address goes to Ashford Borough Council's building control.
A private building control approver is a registered alternative to the council's own team. Registration for private approvers came into force on 6 April 2024, though private building control existed long before that date.
What to tell them
When you ask, describe the conservatory in the terms used above: ground level or not, floor area, how it is separated from the house, whether the heating is extended into it and what roof you plan. A sketch with measurements saves a second call. The answer applies to your conservatory on the date you ask, so keep a note of who said what, and keep any reply from the council with your paperwork, because a buyer's solicitor may ask for it when the house is sold.
If approval is needed, the application is made before the work starts. If the conservatory is exempt, there is nothing to apply for, though the roof still has to be built properly. Our guide to the conservatory exemption and the survey together settle which applies before the work is planned.
