Dulwich Roofing · Homeowner guide
Flat Roof Insulation: How to Improve Energy Efficiency
Improving flat-roof insulation requires more than adding a board beneath the ceiling. The position of insulation and moisture-control layers affects how the roof behaves. Renewal is a useful opportunity to review the whole build-up, including thresholds and upstands.
Plan the insulation with the waterproofing
- Have the proposed roof construction checked for condensation risk.
- Allow for changes in finished roof height at doors and rooflights.
- Coordinate drainage, edge details and any required ventilation.
Ask for a designed build-up and applicable building-control advice before covering up the existing structure.
Ask for a coordinated specification
The proposed build-up should explain the position of insulation and moisture-control layers, and how it connects to the rest of the building. Changes in roof height can affect thresholds, rooflights and flashings. Ask who is responsible for the design and applicable approvals. Avoid enclosing damp or deteriorated materials without assessment and appropriate repair.
Further guidance: Energy Saving Trust: roof and loft insulation.