Warm & cold roofs. Think beyond the covering.

Two approaches, one important question

Where should the insulation sit within your roof, and how will the complete build-up manage heat and moisture? That is the starting point for a discussion about warm and cold roofs.

Broadly, a warm roof places insulation above the structural deck, while a cold roof uses insulation below it with a ventilation arrangement appropriate to the construction. The precise detail depends on the roof type and specification.

The build-up needs to work as a whole

Choosing insulation in isolation is not enough. Structure, airtightness, vapour control, ventilation and the waterproofing layer all interact. An appropriate detail needs to consider how the roof is assembled and how the space below will be used.

This is not a DIY specification. The position and continuity of each layer, junctions and the suitability of the existing structure need project-specific assessment.

New roofs and refurbishment

For a new roof, these questions can be considered early in the design. For an existing roof, available depth, the current build-up and interfaces with doors, walls or rooflights may influence the options.

Share any existing drawings or details with Harry. If the construction is unknown, say so; it is better to identify what needs investigation than assume the layers beneath the covering.

Coordinate insulation with the roofing work

Roof Construction Systems can discuss thermal build-ups alongside flat roofing, pitched roofing or the wider roof construction.

Harry’s whole-system approach is intended to keep these decisions connected. No specific thermal performance figure is promised on this website before a project has been assessed and specified.

Discuss the right approach for your roof

Explain the roof type, how the space below is used and whether you are replacing an existing roof or planning new work. Photos, drawings and the postcode will help start the conversation.

Discuss your project with Harry →