Do not select a replacement roof until the existing frames, connections, base and foundations have been assessed for the proposed loads. A heavier roof can change structural behaviour; a lighter roof does not automatically resolve existing defects.

Evidence for the feasibility review

• Original drawings, approvals and installation records.
• Dimensions and framing system identification.
• Photographs of movement, corrosion, rot, leaks and repairs.
• Foundation or base information, including any trial investigation.
• Proposed roof build-up, weight and support arrangement.
• Changes to ceilings, lighting, ventilation and the house junction.
• Planning and building-control enquiry responses.

The roof supplier’s system certificate should be relevant to the exact configuration, but it cannot establish the capacity of an unknown existing structure.

FAQs

Who checks the frames and foundations before replacement?

Use a suitably competent designer or structural engineer with access to the existing structure and proposed system information.

Does a new roof require changes to existing approvals?

It may. The answer depends on jurisdiction and scope, so confirm planning and building-control requirements before ordering.

Suggested component

A retrofit evidence pack and red-flag checklist; no structural pass/fail result.

Related guides

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