The short answer
For Building Regulations purposes, a solid roof usually takes a conservatory out of its exempt category, so it is treated as an extension and the roof replacement needs a Building Regulations application. Building control checks that the frame and foundations can carry the extra load, as well as insulation and ventilation. Planning is different: a conservatory already counts as an extension for planning purposes. Put your own house's details to the council before you order anything.
Two separate rule books
The question mixes up two systems. Planning permission is about whether a building may be built where and how it is. Building Regulations are about how it is built: structure, fire safety, insulation, ventilation and so on. A conservatory is an extension as far as planning goes, so the limits on size, height and position that apply to extensions apply to it too, whether the roof is glass or tiles. A solid roof does not change that. Our page on planning permission for a conservatory roof sets out the planning side.
Building Regulations are where the roof matters. Conservatories enjoy an exemption, provided they are largely glazed and separated from the house by doors and walls, and have their own heating. The exemption rests on the building being light, mostly glass and thermally separate. Put a solid roof on it and it is no longer a mostly glass structure. That is why replacing a translucent roof with a solid one needs a Building Regulations application.
What building control looks at
The first concern is structure. A solid tiled roof is heavier than glass or polycarbonate. Building control checks that the frame and foundations can take the extra load. Many older conservatories have shallow foundations or lightweight frames that need strengthening, or cannot take a solid roof at all. Our guide on whether your conservatory can take a solid roof covers the frame and foundation checks.
The second concern is thermal performance. A new solid roof should be insulated to modern standards, which is often a reason people choose it, because a glass roof loses heat in winter and gains it in summer. Ventilation and the control of condensation are part of that. Third is weather performance and safety: the roof must shed water and be fixed to resist wind, and any roof windows, rooflights or electrics must meet the rules. Finally, the junction with the house is checked, including the flashing and any change to an existing window or door.
What does not change
Some things stay the same whatever the roof. The room still counts towards the size limits that apply to extensions on your plot, so a conservatory that already uses most of the allowance cannot grow just because the roof is now solid. Neighbours' rights, boundary distances and any covenant on the deeds stay as they were. If you live in a flat, a leasehold house or a property with a management company, the freeholder may have a say on roof changes, so read the lease and ask first.
The route to approval
You can apply to the local authority's building control team or to a registered building control approver, which is the private route. Either will want drawings and the details of the roof system, and will inspect at set stages. When the work is finished you receive a completion certificate, which you should keep. Some proprietary roof systems are certified by LABC as Registered or Assured, which speeds approval, but it does not remove the need for it. See conservatory roofs and Building Regulations for the steps in more detail.
Where the work is notifiable we deal with the paperwork, and prepare what the inspector will want to see. Legal advice is not ours to give, so confirm your own position with the council. Protected status such as a listing or a conservation area designation brings extra restrictions, so raise it with the council early, before the design is fixed and before any materials are ordered.
What changes after a solid roof goes on
A solid roof changes how the room is used and how it is treated. The room becomes warmer, quieter and more usable all year, so people treat it as a living room. That may affect your insurance, which should be told about the change, and how a future buyer or surveyor sees it. A completion certificate is the best evidence that the work was approved. Without one, a buyer's solicitor may ask for an indemnity policy, or may ask for the roof to be regularised. The sale side has its own page in this section, on conservatory roofs and selling your house.
We begin with a free survey, photograph the frame, the base and the wall junction, and give a fixed written quote for the roof. If the structure will not take a solid roof, we say so. See our work in conservatory roof replacement in Basingstoke for the full picture.
Every roof is different. A free survey with photos settles it for yours.
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