The honest answer is usually yes, and here is what that actually involves for you.
Swapping a conservatory roof is not the same as swapping a window. You are replacing a thermal element and changing the load on a structure that was originally designed around a very light roof, so building control has a legitimate interest in it.
This is one of the places where installers differ most. Some quote a roof, fit it and leave. We would rather tell you up front what applies to your job, because the paperwork is what a buyer's solicitor asks for years later.
A conservatory is generally exempt from building regulations while it stays a conservatory: separated from the house by external quality doors, independently heated or unheated, and mostly glazed. Change the roof to something solid and insulated and you may have moved the room out of that exemption.
There are two separate questions to answer. Can the existing frames and base carry the new roof, and does the finished room still qualify as exempt or does it now need to meet the standards of a habitable room.
Any competent installer will calculate the dead load of the proposed roof system against what your frames, dwarf wall and base were built to carry. Lightweight tiled systems exist precisely because most conservatory frames were never designed for a traditional tiled roof.
If the numbers do not work, the answer is not a heavier bet. It is either a lighter system, reinforcement, or replacement frames quoted as part of the same job.
A like for like roof replacement rarely needs planning permission. It becomes a planning question where the roof height or shape changes noticeably, or where you are in a conservation area or working on a listed building.
If either of those applies to your property, check before you order rather than after. We will say so on survey when we think it is a risk.
Whatever route your job takes, ask for these before you pay the balance:
A free survey, a straight answer on the structure and the regulations, then a written quote you can compare with anyone else's.
Not every one, but the majority of solid and insulated roof conversions do, because you are altering a thermal element and often the exemption the conservatory relied on. We tell you which applies to your job before you commit.
We handle notification and liaison as part of the works. You should not be left to arrange your own inspections on a job you have paid an installer to complete.
It usually surfaces during a sale. A regularisation application through the local authority is the normal route, and in some cases indemnity insurance is used instead. Get advice before you exchange rather than after.
Often yes. Retaining the external quality separating doors is one of the conditions that keeps a conservatory in its exempt category, which is why we ask about them on survey.