Warm roof
On flat roofs, a 'warm roof' is one in which the insulation layer is laid on top of roof structure. This results in the structural deck and its supports being at a temperature closer to that of the building’s interior. This is as opposed to a 'cold roof' in which the insulation is below, or within the roof structure, and so the roof structure is closer to the outside temperature.
An 'inverted roof' is a form of warm roof in which the waterproofing layer is beneath the thermal insulation rather than above it.
On pitched roofs, the definition of warm or cold can relate to the entire space below the pitch of the roof, but above the ceiling. This means that a warm roof might be one in which the insulation is installed in line with the rafters (rather than above the roof structure), so that the space under the pitch, ie a loft, attic or other space is insulated and warm. A cold roof in this case would typically have insulation laid above the ceiling so that the loft space below the pitched roof is cold relative to the rest of the property.
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Embedding AI tools into architectural education
Beyond the render: LMU share how student led research is shaping the future of visualisation workflows.
Why document control still fails UK construction projects
A Chartered Quantity Surveyor explains what needs to change and how.
New planning reforms and Warm Homes Bill
Take centre stage at UK Construction Week London.
A brief run down of changes intentions from April in an onwards.
Reslating an ancient water mill
A rare opportunity to record, study and repair early vernacular roofs.
CIOB Apprentice of the Year 2025/26
Construction apprentice from Lincoln Mia Owen wins this years title.
Insulation solutions with less waste for a circular economy
Rob Firman, Technical and Specification Manager, Polyfoam XPS explains.
Recycled waste plastic in construction
Hierarchy, prevention to disposal, plastic types and approaches.
UK Net Zero Carbon Buildings Standard V1 published
Free-to-access technical standard to enable robust proof of a decarbonising built environment.
Prostate Cancer Awareness Month
Why talking about prostate cancer matters in construction.
The Architectural Technology podcast: Where it's AT
Catch up for free, subscribe and share with your network.
The Association of Consultant Architects recap
A reintroduction and recap of ACA President; Patrick Inglis' Autumn update.
The Home Energy Model and its wrappers
From SAP to HEM, EPC for MEES and FHS assessment wrappers.
Future Homes Standard Essentials launched
Future Homes Hub launches new campaign to help sector prepare for the implementation of new building standards.
Building Safety recap February, 2026
Our regular run-down of key building safety related events of the month.
Planning reform: draft NPPF and industry responses.
Last chance to comment on proposed changes to the NPPF.
A Regency palace of colour and sensation. Book review.