How much weight does a solid conservatory roof add?

A polycarbonate roof weighs approximately 3 kg/m² while a solid insulated panel roof weighs 30–40 kg/m² and lightweight tiles 12–18 kg/m². The weight increase of 30–80 kg/m² is significant and may require structural reinforcement of the conservatory frame, ring beam and foundations.

Do I need Building Regulations for a conservatory roof replacement?

Yes. Replacing a glazed conservatory roof with a solid or tiled roof changes it from an exempt conservatory to a habitable extension. Building Regulations approval is required covering structure, thermal insulation (Part L), fire safety (Part B), ventilation (Part F) and electrical safety. The separating doors between conservatory and house can usually be removed.

Will my existing conservatory frame support a solid roof?

It depends on the frame design and the weight increase. Many lightweight tile systems (e.g. Tapco/Metrotile) are designed to work with standard aluminium or PVCu conservatory frames. Heavier solid panels may require frame reinforcement, additional columns or foundation upgrades. A structural assessment is always required.

What insulation do I need in a replacement conservatory roof?

The roof must achieve a U-value of 0.15 W/m²K to comply with Part L. This typically requires 100–150mm of PIR insulation. Most proprietary solid roof systems have factory-fitted insulation that meets Part L. Internal finishing is usually plasterboard with a skim or decorative panels.

Can I remove the doors between the conservatory and house after roof replacement?

Yes, in most cases. Once the conservatory has a solid roof and meets Building Regulations as a habitable room, the separating doors can be removed as they are no longer needed for thermal separation. This is one of the main benefits of roof replacement — it creates usable space all year round.

TradeCalculator

Conservatory Roof Replacement Calculator — Weight & Compliance

Assess structural impact of replacing a conservatory polycarbonate or glass roof with a solid insulated or tiled system including weight increase and Part L compliance.

Roof plan length

Roof plan width

Roof pitch

Existing roof

New roof system

How We Calculate This

This calculator assesses the structural and regulatory impact of replacing a conservatory roof.

Weight analysis

Existing roof weight per m² is compared with the new roof system. The total weight increase determines whether structural reinforcement is needed.

Insulation

U-value is calculated from insulation thickness using the simplified formula U = conductivity / thickness + surface resistances.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.