Building Control on a Conservatory Roof Replacement
Swapping a translucent conservatory roof for a solid one is notifiable building work. It goes to Local Authority Building Control or a Registered Building Control Approver. No competent person scheme covers it, so neither FENSA nor CERTASS can sign it off.
Building control approval · solid roof conversion · England
£200 to £800 no defensible typical
Reasonably evidencedTwo publishers, 2.0x apart on the floor. Checked 20 August 2026.
Who signs off a conservatory roof replacement?
Local Authority Building Control, or a Registered Building Control Approver. Nobody else can. No competent person scheme covers this work, so a FENSA or CERTASS registration is not a route to sign-off.
Approved Inspectors became Registered Building Control Approvers on 6 April 2024. The cost of having a conservatory roof replaced sits on that page: if you want the number first, work out what your roof will cost, then come back and ask who is notifying the council.
What it costs to get signed off
£200 to £800 in England, with no typical, because the only two publishers pricing it disagree by 2.0x on the floor and 1.74x on the ceiling. Our likely reading, stated as a reading and not a fact: the lower band prices the application alone, the higher one includes the inspection regime. Checked 20 August 2026.
| Fee or conditional cost | Low | High | Evidence | Sources |
|---|---|---|---|---|
| Building control approval, solid roof conversion | £200 | £800 | Reasonably | Two UK cost publishers, 2026 and March 2026 |
| Structural engineer's report | £300 | £500 | Thin | Google AI Overview synthesis, no publisher attributed |
| Structural reinforcement, if the frame cannot carry it | £800 | £4,000 | Reasonably | Two UK cost publishers, 2026 and May 2026 |
| Upgrading the conservatory into a heated envelope | £1,200 | £2,900 | Thin | One UK cost publisher, May 2026 |
| Planning application fee | no figure | no figure | Gap | Our register carries no planning fee row at all |
Sources: three UK cost publishers, dated 2026, March 2026 and May 2026, and one Google AI Overview synthesis Google does not attribute and we could not trace. Checked 20 August 2026.
The planning fee is a gap, and we are leaving it as one. No planning application fee appears anywhere on this page, because our register holds no planning row at all. An invented statutory fee is exactly the figure a homeowner repeats to a council officer. What would close it: the current householder application fee, published, cited and dated.
Why FENSA cannot sign this off
FENSA is the Fenestration Self-Assessment Scheme, run by FENSA Limited, company 03058561, majority owned by the Glass and Glazing Federation. It is a real competent person scheme under Schedule 3 of the Building Regulations 2010, and its scope is replacement windows, doors, roof windows and rooflights. A conservatory roof is none of those.
“the installation of a conservatory or porch falls outside the scope of the FENSA competent persons scheme”, because “under the Building Regulations they are generally not considered to be part of the thermal envelope of the property”.
On the case that matters here, a heated conservatory, FENSA's own guidance is that “The installation would need to be referred to the relevant Local Authority Building Control, not the FENSA scheme.” There is exactly one FENSA-registrable job in a conservatory: the inner door to the house, if it is more than half glazed and replaced like for like.
A FENSA certificate after a roof replacement answers a different question. It says a window or door was fitted to standard. It does not tell a buyer's solicitor the roof was ever notified.
Why CERTASS cannot either, and what CQ-Assured actually is
CERTASS Limited, company 04350234, runs a competent person scheme with the same fenestration scope as FENSA plus wall insulation. Conservatories are excluded in writing, under CERTASS's own heading “What cannot Be Registered”: “Porches and conservatories”, retrieved from certass.co.uk on 20 August 2026.
CQ-Assured is where most of the confusion comes from. It is a workmanship and product certification scheme, and its own claim is to be the only scheme in the industry covering the installation of both conservatories and conservatory warm roofs, across thirteen work scopes. That claim is true. It is also not building control.
CQ-Assured issues a Certificate of Conformity. That is not a Building Regulations Compliance Certificate, and the scheme does not notify your local authority. If it is the only paperwork you are offered at the end, the work has not been signed off by anyone with the power to sign it off.
The same care applies to system certificates. Every publicly downloadable LABC certificate we located in this category is expired on its face: Guardian EW320 to 8 August 2016, SupaLite EW277 to 26 June 2016, Equinox EW606 to 19 July 2017. The live register is members-only, and Guardian's BBA certificate 13/5078 was not on the BBA register at all. Ask for the number and its validity window, and treat a bare approval claim as unproven without both. Which system you are sold is a separate question, settled on solid, tiled, warm and glass roofs compared.
When a roof replacement becomes regulated building work
A conservatory is exempt from most of the Building Regulations under Schedule 2 Class 7 of the Building Regulations 2010, which is why nobody inspected it when it was built. That exemption is conditional. Regulation 9(1)(b) says it survives further work only if the structure is still a building of the kind Schedule 2 describes. Take the glazing out of the roof and it is not, and the government said so in its 2013 circular: the exemption may no longer apply where “the amount of glazing to the walls or roof [is] significantly reduced”.
Three things then follow at once. The job is a material alteration under regulation 3(c). Regulation 23(2) bites, because replacing more than half a thermal element triggers full energy compliance. And the work becomes notifiable under regulation 12, by a building notice or a full-plans application.
What comes with it is wider than most quotations suggest: Parts A, C, L, B2 and B3, F for ventilation including the roof void, H3 and H5 for rainwater, P for lighting, and K if the glazed units change. What does not: you are not required to upgrade existing walls, floors, windows or doors, and building control cannot demand a cavity tray retrospectively on the original structure.
None of it applies to a like-for-like reglaze. It applies when the roof stops being translucent, which is the point of a solid roof for your conservatory, and why a tiled roof on an existing conservatory is a different job in law.
What you must be given at the end, and what to do if you are not
Read this out on the sales visit, not afterwards.
- A completion certificate from the local authority or the RBCA that took the job on. This is the document that matters when you sell.
- The application reference, so you can check with the council yourself.
- The U-value the finished roof achieves, in W/m²K, written down. A figure for your roof, not a brochure claim about the system.
- Evidence the frames were checked before the roof went on, and what was found.
- Not enough on their own: a Certificate of Conformity, a FENSA certificate, an insurance-backed guarantee, a manufacturer's certificate. None is building control sign-off.
If the job is done and nothing was notified, your local authority building control team is still the body to speak to, and better you raise it than a buyer's solicitor in four years. We publish no cost for putting it right, because our register holds none. If a quotation is short on any of the five, have local installers price it again with the sign-off question asked up front.
Ask each installer who is notifying building control
Then get it priced. Six questions, roof condition first, phone number last.
What would yours cost?
Six questions, about sixty seconds.
Check what your roof will cost, or go to quotes from local roof installers and use the sign-off question as your first filter.
Frame load and mullion reinforcement
LABC's addendum on solid roofs to conservatories puts the added load from a lightweight composite roof at approximately 0.5 kN/m, “less than 10% over a typical translucent roof”. Foundations are rarely the issue: “In most cases a 150 mm thick concrete strip foundation or reinforced concrete slab which bears onto original ground will be adequate”.
The risk is the part most quotations never mention. Frames built for a polycarbonate roof may be reinforced only for that lighter load, so the question is whether your mullions contain steel, verified by pilot holes or a magnet test. Where there is none, new frames or added reinforcement may be needed: the £800 to £4,000 line above, Reasonably evidenced, two publishers, conditional on the survey. Checked 20 August 2026.
Planning permission is a separate question, and the class is C
Changing a conservatory roof is permitted development under Class C of Part 1, Schedule 2 of the GPDO 2015, “any other alteration to the roof of a dwellinghouse”. It is not Class A, which expressly excludes roof alterations at A.1(k)(iv). Citing Class A here is the commonest factual error in this category.
Two Class C limits matter: no protrusion more than 0.15 m beyond the plane of the original roof slope, and nothing above the highest part of the original roof. Rights are removed on Article 2(3) designated land, listed buildings and under Article 4 directions. One grey area we flag rather than settle: whether an authority treats a height-increasing solid roof under Class C or Class A.
The standard the roof has to meet
The edition in force is Approved Document L Volume 1, 2021 with the 2023 amendments, applying since 15 June 2022. Table 4.2 sets the limiting U-values in an existing dwelling: 0.15 W/m²K for a roof, 1.4 W/m²K or WER Band B for a window or roof window, 2.2 W/m²K for a rooflight. A replacement element must clear two tests at once, per paragraphs 4.7 and 4.8: no worse than what it replaces, and no worse than Table 4.2.
One detail commonly stated backwards: roof windows are calculated in the vertical plane and rooflights in the horizontal, per paragraph 4.5. The 2026 edition carries identical numbers and is not in force until 24 March 2027. Zero of the thirteen competing pages we surveyed publish any W/m²K figure, which is worth holding next to whatever the Conservatory Cost Calculator says the job costs.
Questions people ask first
Can FENSA sign off a new conservatory roof?
Is CERTASS CQ-Assured the same as building control approval?
How much is building control on a conservatory roof?
Do I need planning permission to change a conservatory roof?
What if my installer never notified anybody?
Sources for this page
All retrieved and checked 20 August 2026.
The full list, with what each source is trusted for, is on sources we use. Checked 20 August 2026, next check due 20 November 2026.
Find out what yours costs
Six questions, about sixty seconds, and an estimate built from published UK figures with every source shown. Then up to four local installers can quote you, if you want them to.