Replacing a conservatory roof with a solid or tiled roof: the rules that apply
It can usually be done, but the frames, the base and the building regulations decide it, not the brochure.
You can usually replace a glazed or polycarbonate conservatory roof with a solid one, but it is building work. Taking away most of the roof glazing ends the conservatory’s exemption from building regulations, so under LABC’s guidance the new roof needs approval, insulation to the current standard and proof that the frames and base can carry it.
The short version
- A conservatory is only exempt from building regulations while a significant proportion of its roof and walls is glazed. A solid roof removes that, so building control has to sign the new roof off.
- The new roof is treated as a new thermal element. Under the Approved Document L in force today, that means a U-value of 0.15 or better, the same figure as a roof on any other extension.
- Before anything is ordered, somebody should check whether the window frames have steel in them and dig a trial hole to see what the base is sitting on. If nobody mentions either, ask why, because those two checks decide whether the job is safe.
- The “LABC approved” badge on some roof systems refers to a scheme LABC decided to discontinue in November 2021 and has since closed. LABC said any such certificate should be disregarded.
- The old “four-year rule” for building work done without planning permission no longer applies in England to work finished on or after 25 April 2024. The period is now ten years.
Building regulations
Why a solid roof ends the exemption
Most conservatories were built without building regulations approval, and that was legal. Schedule 2 of the Building Regulations 2010 exempts a conservatory or porch added at ground level with a floor area that does not exceed 30 square metres, as long as its glazing meets the safety glazing rules.
The energy efficiency rules, in regulation 21 and explained in Approved Document L, add conditions of their own: the conservatory has to stay separated from the house by walls, doors or windows, and the house’s heating system must not be extended into it.
What the regulations do not do is give a percentage. Nothing in the current rules says a conservatory is a conservatory up to so much solid roof. The working test comes from a government circular of July 2013, which LABC, the body that represents council building control teams, quotes in its guidance on solid roofs to conservatories: to stay exempt, a conservatory must have a significant proportion of its roof and walls glazed, and if that glazing is significantly reduced it can no longer be treated as an exempt conservatory. BCP Council uses the same words on its own page about which buildings need approval: “a significant proportion of the roof and walls glazed (no % given)”.
So the moment the glass or polycarbonate comes off and a solid roof goes on, the building control body is entitled to say the structure is no longer exempt. LABC’s guidance treats the job as a material alteration, and it is precise about how far that reaches. The new roof has to meet the regulations in full. The existing walls, floor, windows and doors only have to end up no worse than they were before. In plain terms, you are not forced to rebuild the whole conservatory to modern standards, but the roof you are paying for has to be done properly.
Two things make it worse, and both happen often. If the doors between the house and the conservatory come out, or a radiator from the house heating goes in, the thermal separation has gone. Approved Document L then says the conservatory should be treated as an extension, and the walls, floor and glazing are judged as an extension rather than just the roof. BCP’s page also points out that widening the opening into an exempt conservatory still needs approval, “for the structural alteration to widen the opening”.
The structure
What has to be checked before the roof is ordered
Start with the question a glossy brochure will not ask: was this conservatory ever built to hold a heavier roof? LABC’s guidance is blunt about it. A glazed roof usually sits on frames designed to carry glass. A polycarbonate roof may sit on frames with only enough reinforcement for polycarbonate. And a traditional tiled roof put on by somebody who has not checked may “not have taken into account the adequacy of the existing structure to carry increased loading”.
The checks are not complicated. LABC does accept that on a lightweight roof with no sign of movement in the structure a trial hole is sometimes not needed, so ask the surveyor rather than assume either way.
| Check | How it is done | What happens if it fails |
|---|---|---|
| Do the frames carry load? | Drill pilot holes in the uPVC frames, or test with a magnet, to find out whether there is a steel core running the full height of each upright. | New load-bearing frames, or extra structural posts fitted beside the existing ones. |
| Can the base take it? | Dig a trial hole beside the base and photograph it. LABC says a 150 mm concrete strip or reinforced slab bearing onto original ground is adequate in most cases. | Further investigation, particularly near drains, tree roots or filled ground. |
| Is the structure already moving? | Look for cracks, gaps at the house wall and doors that have started to bind. | Movement has to be explained before more weight is added. |
| Will it keep the weather out? | Check the roof covering suits the pitch, and check the flashing into the house wall and the gutters. | A different covering or a different detail at the abutment. |
| Is it insulated to standard? | Compare the roof build-up with the limiting U-value for a new roof. | Thicker or better insulation before sign-off. |
| Is there ventilation? | Check the roof void and the room underneath for condensation risk. | Vents or a different build-up. |
On the insulation figure: the version of Approved Document L in force today is the 2021 edition incorporating the 2023 amendments. Its table of limiting values for new fabric in existing homes puts a roof at 0.15 W/m²K, and paragraph 10.13 applies that to the new and replacement elements of a conservatory that is no longer exempt. A 2026 edition has been published, but it does not take effect until 24 March 2027, and it keeps the same 0.15 for a roof. Any roof system you are offered should come with a U-value calculation for the build-up being proposed, not a number from a brochure.
Lighting is the other detail people forget. If downlights or sockets are going into the new ceiling, LABC’s checklist asks for the electrical certificate, and the insulation and vapour control layer must not be cut through carelessly to fit them. That certificate comes from whoever does the electrical work, so make sure the quote says who that is.
Your options
Four ways to replace the roof, and what each one means
Most products on the market are a version of one of four things. The paperwork and the structural question change a great deal between them, so work out which one you are actually being quoted for.
| Route | Is it still an exempt conservatory? | The structural question | Best suited to |
|---|---|---|---|
| New glazed or polycarbonate roof | Normally yes, because the roof stays glazed. The glazing still has to meet the safety glazing rules. | Small. The load is similar to what the frames already carry. | A sound conservatory where the problem is leaking bars, failed seals or tired sheets. |
| Lightweight solid or tiled roof system | No. It needs building regulations approval as a new roof. | Real, but manageable. LABC’s 2018 addendum, written for systems then registered under its scheme, put the extra load at less than 10% over a typical translucent roof, provided a visual check finds no cracking or movement. | A conservatory that is too hot and too cold, on a base and frames that check out. |
| Traditional timber roof with standard tiles or slate | No. It is approved as a new roof, and in practice is designed like an extension roof. | Large. LABC warns that a traditional tiled roof may not have taken account of whether the existing structure can carry the extra load, so expect new structure: posts, a beam or new walls. | A conservatory being turned into a proper room, where the budget allows for the structure. |
| Insulated ceiling or overclad kit over the existing roof | Usually no. LABC says that significantly reducing the roof’s translucence ends the exemption, just as a new roof does. | Usually small, but the frames still carry whatever is added. | A tight budget, accepting that building control still applies. |
There is one more option that gets less attention than it should: keep the glass roof and fix what is wrong with it. A conservatory that leaks at one glazing bar, or along the box gutter, does not need a new roof. A conservatory that is unbearable in July and unusable in January is a different problem, and that is the one a solid roof actually solves.
If you are weighing up tiles, the same choice between concrete and clay tiles applies to a conservatory as to a house, with one extra constraint: conservatory roofs are often shallow, and every tile has a minimum pitch set by its maker. LABC lists checking the materials against the pitch as one of the site checks. Lightweight systems usually use their own tile or slate product designed for lower pitches, which is part of why they exist.
Reading the brochures
The “LABC approved” badge, and why it no longer means anything
Some roof systems still carry an LABC logo or describe themselves as LABC registered, LABC approved or LABC Assured. The scheme behind those words started as LABC Registered Details and was later renamed LABC Assured. It was a way for a manufacturer to have a standard design checked once rather than on every job.
It has gone. LABC’s own page on the scheme, archived in March 2026 before it was taken down, said the LABC Board decided to discontinue it in November 2021, that the scheme had closed, and that any certificates provided by manufacturers should be disregarded. The same page made the point that matters most to a homeowner: it has never been the case that a product had to be registered on the scheme for building control to accept it, and whether a product is suitable on a particular job is decided by the local authority.
So treat the badge as neither a warning nor a reassurance. A lightweight system can be a perfectly good roof. What makes it acceptable on your conservatory is the structural check, the U-value calculation and the building control sign-off for your job, not a logo. If a salesperson tells you that the badge means you do not need building control, that is wrong, and it is worth asking what else in the pitch is wrong too.
Planning permission
Do you need planning permission for a solid conservatory roof?
Usually not, but nobody can give you a national yes, because no rule deals with this exact job. The Planning Portal says a conservatory falls within the same planning rules as any other home extension. Re-roofing one is an alteration to a house, and is generally treated as falling under the householder permitted development rules in Class A.
Those rules have height limits, and a solid roof can trip them, because it is usually deeper than glazing. Class A does not allow the eaves of an extension to be higher than the eaves of the house, a single-storey extension to be more than 4 metres high, or the eaves to exceed 3 metres within 2 metres of a boundary. If the new roof lifts the conservatory past any of those, permitted development may not cover it.
One detail in those rules is worth knowing. Condition A.3(a) says the materials used in exterior work must look similar to the house, “other than materials used in the construction of a conservatory”. That exception is what lets a white uPVC and glass conservatory sit against a brick house. Once the roof is tiled, the sensible reading is that the tiles should look like they belong to the house. Whether your council agrees on your house is its judgement, not ours.
Four situations change the answer:
- A listed building. Works that affect its character need listed building consent, whether or not planning permission is needed.
- A flat or maisonette. Householder permitted development rights belong to houses, so a flat with a conservatory needs to ask the council.
- Rights removed by condition or direction. Some permissions, especially on newer estates, remove permitted development rights by condition, and an Article 4 direction can do the same across a whole area. Check the planning history of the house.
- A conservation area. Permitted development still applies, but with tighter limits, and the appearance of the roof will be looked at more closely. Our guide to re-roofing in a conservation area covers what changes.
If you want certainty rather than an opinion, apply for a lawful development certificate for the proposed work. It is the council confirming in writing that planning permission is not needed, and it is the document a buyer’s solicitor will understand when you come to sell. It does not cover building regulations, which are a separate approval. If the difference between the two is unclear, our post on planning permission, building regulations and listed building consent explains what each one is for, and whether you need planning permission to replace a roof covers the main house.
The four-year rule
What people mean by the “four-year conservatory rule”, and why it is now ten
The “four-year rule” you will see mentioned online is not a conservatory rule at all. It was the time limit after which a council could no longer take planning enforcement action against building work done without permission. People used it to argue that anything standing for four years was safe.
In England that changed on 25 April 2024. The time limit in section 171B of the Town and Country Planning Act 1990 is now ten years from the date the work was substantially completed. Under the transitional rules, the change does not apply where the work was substantially completed before 25 April 2024, so older work keeps the old four-year period. Anything done now faces ten.
Building regulations have their own clock, and for work done now it is also ten years. Under section 36 of the Building Act 1984, as extended by the Building Safety Act 2022, a council can serve a notice requiring work that breaches the regulations to be taken down or altered for up to ten years after the work was completed. Older work may fall under the previous, shorter limit, which is a question for a solicitor rather than a roofer. A solid roof put on without building control approval is exactly the kind of work that notice exists for. It is also one of the things a buyer’s solicitor tends to ask about, because the completion certificate either exists or it does not.
Living with it
Will it be darker, and what else changes?
Yes, it will be darker. A glazed roof lets in light from above all day, and a solid one does not. How much that matters depends on which way the conservatory faces and what is beyond it. A south-facing room with big side windows will still be bright.
A north- or east-facing conservatory that is the only window to a kitchen or dining room behind it can leave that inner room noticeably gloomier, and that room is the one people forget to think about.
Most systems let you put glazed panels or rooflights into the solid roof. They help, and they are worth the money on a darker plot, but every rooflight has to meet its own limiting value, 2.2 W/m²K in the current Approved Document L. Ask for the rooflights to be included in the roof’s U-value calculation rather than added afterwards.
The trade is a room that stays usable through more of the year. A solid, insulated roof stops the greenhouse heat in summer and holds warmth in winter far better than a single layer of polycarbonate. Rain is quieter too. What it will not do is turn the conservatory into part of the house unless the walls, floor and glazing are dealt with as well, which is the point at which the job becomes an extension and should be priced like one. If that is where you are heading, our house extensions page is the better starting point.
Inside, the new ceiling is usually plasterboard, finished with a skim coat so it looks like any other ceiling in the house. That is plastering work and it belongs on the quote, along with making good where the old roof met the wall.
Do not climb onto the roof to look. HSE lists rooflights and glass as fragile surfaces and says every roof should be treated as fragile until a competent person has confirmed otherwise. Treat polycarbonate sheets and glazing bars as if they will not take your weight. Look from the ground, from an upstairs window, or from inside.
What to do next
What to ask before you sign anything
- Decide what problem you are solving. If it is a leak, ask for a repair price first. If it is heat and cold, a solid roof is the right conversation.
- Ask who is applying for building regulations approval and to which body, the council or a registered building control approver. The answer should be a name, not “you won’t need it”.
- Ask how the frames will be checked for steel and whether a trial hole will be dug at the base. Both should be settled before the roof is ordered, not on the day it arrives.
- Ask for the U-value calculation for the roof as specified, including any rooflights, and check that it is 0.15 or lower.
- Make sure the quote covers the flashing into the house wall, the gutters, the internal ceiling finish and any electrical work, and says who does each. What a roofing quote should include has the full checklist.
- Keep the doors between the house and the conservatory, and keep the house heating out of it, unless you are deliberately turning it into an extension.
- On a listed building, a flat, or a house with restricted rights, talk to the council before anything else.
Along the coast here the roof also has to cope with wind. A solid roof is fixed and detailed differently from glazing, and the way wind lifts tiles applies to a conservatory as much as to the house.
Conservatory roof replacement is part of our roofing work across Bournemouth, Poole and Christchurch, and the insulation in the build-up is the same insulation work we do on any other roof. Thomas Hannen comes out and looks at the frames and the roof you have now, and you get a free written itemised quote that covers the items above that apply to your job, including what still has to be checked, such as a trial hole at the base, before anything is ordered.
Questions
Common questions
Do I need building regulations approval to put a solid roof on my conservatory?
In almost every case, yes. A conservatory is exempt only while a significant proportion of its roof and walls is glazed. Replacing a glazed or polycarbonate roof with a solid one removes that, so the new roof has to be approved and has to meet the current insulation standard, a U-value of 0.15 W/m²K for a roof.
Do I need planning permission for a tiled conservatory roof?
Usually not, because re-roofing a conservatory on a house normally falls under householder permitted development. It also has to stay within the Class A height limits. Listed buildings, flats, houses whose rights were removed by a planning condition or an Article 4 direction, and some conservation area properties are the exceptions. A lawful development certificate gives you the council's answer in writing.
What is the four-year rule for conservatories?
It is the old time limit for planning enforcement, not a conservatory rule. In England it became ten years for work substantially completed on or after 25 April 2024. Building regulations have a separate ten-year limit for work done now, under section 36 of the Building Act 1984.
Will a tiled roof make my conservatory darker?
Yes. A solid roof cuts out the light from above, which matters most on a north- or east-facing conservatory and for any room behind it. Glazed panels or rooflights in the new roof help, and they should be included in the roof's U-value calculation.
Can I stand on my conservatory roof to check it?
No. HSE lists glass and rooflights as fragile surfaces, so treat polycarbonate sheets and glazing bars as if they will not carry your weight. Look from the ground, from an upstairs window, or from inside the conservatory.
Read next
Related advice
The guides below pick up where this one leaves off, and the roofing page covers the work itself and the places we cover, if you would rather have the job looked at.
- Planning permission, building regulations, listed building consent: which one you actually need
- Snow on a flat roof or a conservatory: what actually carries the load
- What a roofing quote should include: the line items to look for
- Building notice, full plans or a competent person: which applies to your job
Who wrote this
Thomas Hannen
Thomas owns Bournemouth Roofing & Building and prices every job himself instead of sending somebody else. The company is Bournemouth Roofing & Building Ltd, number 15471719, registered in England and Wales. If you want to talk something through before you commit to anything, the site visit and the written itemised quote are both free.
Free quote
Thinking about a solid roof on your conservatory?
Thomas comes out, looks at the frames and the roof you have now, and puts what he found in a written, itemised quote, including what still needs checking and whether a solid roof is the right answer at all.