Replacing a glazed or polycarbonate conservatory roof with a solid insulated one is the most popular conservatory upgrade in Britain, and it is the one where the answer depends least on the product and most on what is holding it up. A tiled roof is several times the weight of the polycarbonate it replaces, on a frame and a dwarf wall sized for the original.
Lightweight conservatory roof replacement: the weight question comes first
Polycarbonate is very light, glass is heavier, and a tiled or slated roof is heavier again. The existing frame, the dwarf wall and the foundation were designed for what was fitted originally, so a competent installer assesses them before quoting and says plainly where strengthening or a new frame is needed. This is why lightweight systems exist: an engineered frame with lightweight tiles or shingles designed to sit on conservatory frames, weighing a fraction of a conventional tiled roof.
Insulated conservatory roof cost: what the build up contains
A structural frame spanning between the existing frame and the house wall, insulation between and over the rafters, a vapour control layer on the warm side, a ventilated or fully filled build up depending on the system, a covering of tiles, slates or shingles, and a plastered or boarded ceiling inside. Most systems include one or more rooflights, because a solid roof over a glazed room makes it considerably darker and the light has to come back from somewhere.
Where the building regulations come in
A conservatory that was exempt from the building regulations was exempt partly because it was substantially glazed and thermally separated from the house. Putting a solid roof on changes that, and the work is generally notifiable: the new roof is a thermal element with a performance requirement under Approved Document L, and the structural alteration falls under Approved Document A. Ask the installer which route is being used and insist on the completion paperwork, because a buyer's surveyor will ask.
Hybrid, composite and aluminium systems for tiled conservatory roofs
A hybrid roof keeps glazed panels within a solid insulated frame, which is a sensible compromise where the room would otherwise go dark. Composite panel systems use a factory made insulated panel rather than a site built rafter and insulation build up, and go on quickly. Aluminium framed systems give slim rafters and long spans for their weight. All three are legitimate; what distinguishes a good quote is whether the thermal performance and the structural check are stated rather than implied.
What changes in a conservatory with solid roof
The room becomes usable year round, quieter in rain, and much less prone to overheating in summer, which is the single most common complaint about a glazed conservatory. It becomes darker, which is why rooflights matter, and it may need heating and ventilation it never had. Where the room was always freezing in winter and unusable in July, this is the change that fixes both, and it is worth budgeting for the ventilation as part of it rather than discovering condensation afterwards.
Questions people ask about solid conservatory roofs
Can I replace conservatory roof with tiles on an existing frame?
Many can with a lightweight system and some cannot without strengthening. It depends on the frame, the dwarf wall and the foundation, and it is assessed rather than assumed. An installer who quotes without looking at the base has not answered the question.
Does a solid conservatory roof need building regulations approval?
Generally yes. Replacing a glazed roof with a solid one is a structural and thermal alteration, and the exemption a conservatory enjoyed usually does not survive it. Get the completion certificate.
Will the room be too dark?
It will be darker, which is why most systems include rooflights. Decide how many and where at design stage, because adding them afterwards means opening the new roof.
Are lightweight conservatory roof tiles as good as real ones?
For this purpose it is usually better, because it achieves the look and the insulation without the weight the existing structure cannot carry. Ask for the system name and its certification.