Few parts of a conservatory project cause as much confusion as the rules. Some owners are told that a conservatory needs no paperwork at all, and that is true of the building as it stands. Others hear that a tiled roof needs full approval, and that is true too. The difference lies in what the roof does to the structure beneath it. A like-for-like change leaves the loads where they were, while a heavier, insulated roof alters them, and building control exists to check that the alteration is safe and efficient. This guide separates the cases, explains the application, and flags where to ask your own authority. It is general information, not legal advice. For the roof options themselves, see our Basingstoke conservatory roofs service page.
The rule that catches most owners out
The key fact is simple. A translucent roof, whether glass or polycarbonate, can be exchanged for a solid roof only after a Building Regulations application. The reason is not the appearance of the new roof but its weight and thermal behaviour. Building control will want to see that the frame and the foundations can take the added load, and that the new roof meets the energy rules for a roof forming part of a heated space.
Compare this with the case where you simply swap one light roof for another light one, say old polycarbonate for new glass or a better-grade multiwall sheet. If the new roof is of similar weight and the conservatory remains a separate, unheated structure, the question does not usually arise in the same way. But "usually" is doing a lot of work in that sentence. Whether your plan needs an application depends on the details, so check with your building control body before you order anything.
There is also a general weight test that applies to any re-covered roof. A new covering that is 15% or more heavier than the old one needs approval, and the structure may need strengthening. A solid tiled roof will clear that threshold with ease on almost any conservatory. Our note on how much a tiled conservatory roof weighs shows the comparison.
What building control looks at
Building Regulations are split into parts, called Approved Documents, each covering a topic. Three matter most for a conservatory roof, and it helps to know them by name when you speak to an inspector.
Approved Document A deals with structure. This is the load question: can the foundations, the dwarf walls, the posts, the eaves beam and the junction with the house wall carry the new roof together with wind and snow? Expect to be asked for the dimensions of the frame members, evidence of the footing depth and, for anything borderline, a calculation from a structural engineer. Our guide to the frame and foundation checks goes into the practicalities.
Approved Document L deals with energy. A solid roof forms part of a heated space and has to meet minimum standards of thermal performance, which is why the build-up includes insulation of a stated type and thickness. Any roof windows or rooflights you put into the new roof have to meet the figures for existing homes in the 2021 edition: 1.4 W/m²K for roof windows, or Window Energy Rating Band B, and 2.2 W/m²K for rooflights. A roof window is a unit set into the pitch, while a rooflight is a fixed or opening glazed panel, sometimes a lantern.
The weathering details, ventilation and drainage are checked as well, on site, as the work progresses. The inspector looks at flashings, at the fixing of the covering, and at how rainwater is carried away.
Who you apply to
You have two routes. One is your council's building control team. The other is a private inspector, known since April 2024 as a registered building control approver. Both do the same job against the same rules, and the choice is yours. Councils tend to be a familiar default, while private approvers may offer more flexible appointments. Ask each what they charge and how many inspections they expect, and compare.
The authority you speak to depends on where you live. Around Basingstoke the planning and building control functions sit with the borough council, but our work reaches across 30 miles, so the right team varies with the town. If you live in Hart, Test Valley, West Berkshire, Wokingham or elsewhere in our area, use that council's website, such as testvalley.gov.uk, to find the right building control contact. We deal with the Building Regulations side of the application wherever the work is notifiable, so you do not have to learn the forms yourself.
How the application and inspections run
The process follows a sequence that is easier to plan around once you know it.
- Survey and design. We survey the conservatory, record the frame, base and junctions, and agree the roof build-up with you.
- Application. The drawings and details go to the building control body, together with any engineer's calculation. Building work should not start until the notice has been given and the body has agreed to act.
- Foundation check. If the footing needs exposing, the inspector sees it before it is covered over again.
- Structure and insulation. The inspector visits during the work to check the new framing, the fixings and the insulation before they are hidden behind linings.
- Completion. After the final inspection, the body issues a completion certificate. Keep it. A buyer's solicitor will ask for it if you sell.
Timing varies by authority and by how complete the first submission is, so we can only say that you should build in time for the plan check ahead of the start date. Ask the body for its current turnaround.
Registered systems and what they do and do not do
Several solid conservatory roof products are sold with a registered or assured status through the Local Authority Building Control (LABC) scheme. The status means the design has already been assessed, so the paperwork moves faster and the inspector can concentrate on the parts particular to your house. It does not replace the application. Your frame and your foundations are still looked at on their own merits, since a system designed for a typical conservatory may not suit yours.
That is worth knowing when you compare quotes. A seller who says a roof "needs no building regs" because it is a registered system has misread the scheme. Ask the company what they will submit, who will inspect, and whether the quote includes engineering and fees. We include the notifiable work in our fixed written quote after the survey. For the price drivers, see what a new conservatory roof costs.
Planning permission is a separate question
Building Regulations and planning permission are different regimes, and approval under one does not cover the other. Most conservatory roof replacements stay within permitted development, but listed buildings, conservation areas and homes with particular restrictions can be different. If your house is listed, or sits in a conservation area, ask the council's conservation officer first, since materials and appearance may need consent. Our guide on planning permission for a conservatory roof deals with that side. If you want roof windows in the new roof, the rules on projection and glazing are in our roof windows service page, and we will not repeat them here.
Roof windows, ventilation and the details inspectors notice
A few details recur on inspections. The first is how the new roof meets the house wall. The flashing at the abutment has to be properly dressed and the roof covering lapped under it, and any existing damp issues at the junction are better resolved before the new roof hides them. The second is ventilation: a tighter roof makes a room less leaky, so the installer should show where fresh air enters, whether through trickle vents or an opening roof window. Our answer on whether a conservatory roof needs vents explains the thinking.
The third is fire and safety glazing near the ground, which depends on the layout of the building, and your inspector will advise on it. The fourth is the finish and records: photographs taken during the work, product data sheets and the calculation, all of which go into the file that supports your completion certificate.
Questions to put to any roofer before you sign
Because the rules are widely misunderstood, a handful of direct questions will tell you a lot about a quote. Ask who is making the application and whether its fee is in the price. Ask whether the quote includes an engineer's calculation if your frame turns out to be marginal, or whether that is an extra. Ask which building control body will inspect and at what stages, and who will be on site when the inspector visits.
Then ask what happens if the footing proves too shallow. A roofer who has not looked at the base cannot answer that honestly, and a quote given from a photograph or over the phone has skipped the part of the job that carries the most risk. Ask too for the completion certificate to be named as part of the handover, so that it does not get forgotten once the scaffold is down.
Finally, ask what the roof will weigh compared with the one it replaces, and which layers make up the build-up. The answer should be specific: the type of insulation, the covering, the lining and the fixings. Vague replies such as "it's all standard" are a sign that nobody has worked it out for your conservatory. The point of the questions is not to catch anyone out. It is to make sure the application, the inspection and the building all line up before work begins, so you are not left with an unsigned roof on a house you may one day want to sell.
What to do next
Start with a survey, because the application cannot be written until the structure is known. We photograph your frame, base and junctions, explain what we found in plain language, and tell you whether your plan needs an application and what it would contain. If a smaller change would get you what you want, we say so. You then receive a fixed written quote, with a typical UK range for a solid tiled roof of £6,100 to £15,000 as a rough guide before the survey.
The finished work is covered by a ten-year workmanship guarantee that we put in writing. Contact us on 01256 213956 or by WhatsApp to arrange the visit.
