Cold roof
A cold roof is roof in which the thermal insulation layer is located immediately above or between the ceiling joists meaning that everything above the insulation, such as the rafters, and any roof space, will be colder than the living space below it.
When warm, damp air permeates up through the ceiling and reaches the cold roof space, the change in temperature can result in condensation forming. Adequate roof space ventilation must be provided therefore to remove this air. This requirement, and the need for preventative measures to tackle cold bridging, means that warm roofs can be preferable.
A warm roof is one in which the insulation layer is laid on top of roof structure (or above the loft or attic space in the case of pitched roofs) so that the roof structure or roof space is closer to the inside temperature and so the risk of condensation is reduced.
Particular care must be taken when installing loft insulation, as this can convert a pitched roof from a warm to a cold roof. Ventilation must then be provided to prevent the accumulation of moist air and so condensation, as this can cause the roof structure to deteriorate and ultimately to fail.
[edit] Related articles on Designing Buildings
Featured articles and news
Plumbing and heating for sustainability in new properties
Technical Engineer runs through changes in regulations, innovations in materials, and product systems.
Awareness of the Carbon Border Adjustment Mechanism
What CBAM is and what to do about it.
The new towns and strategic environmental assessments
12 locations of the New Towns Taskforce reduced to 7 within the new towns draft programme and open consultation.
Buildings that changed the future of architecture. Book review.
The Sustainability Pathfinder© Handbook
Built environment agency launches free Pathfinder© tool to help businesses progress sustainability strategies.
Government outcome to the late payment consultation, ECA reacts.
IHBC 2025 Gus Astley Student Award winners
Work on the role of hewing in UK historic conservation a win for Jack Parker of Oxford Brookes University.
Future Homes Building Standards and plug-in solar
Parts F and L amendments, the availability of solar panels and industry responses.
How later living housing can help solve the housing crisis
Unlocking homes, unlocking lives.
Preparing safety case reports for HRBs under the BSA
A new practical guide to preparing structural inputs for safety cases and safety case reports published by IStructE.
Male construction workers and prostate cancer
CIOB and Prostate Cancer UK encourage awareness of prostate cancer risks, and what to do about it.
The changed R&D tax landscape for Architects
Specialist gives a recap on tax changes for Research and Development, via the ACA newsletter.
Structured product data as a competitive advantage
NBS explain why accessible product data that works across digital systems is key.
Welsh retrofit workforce assessment
Welsh Government report confirms Wales faces major electrical skills shortage, warns ECA.
A now architectural practice looks back at its concept project for a sustainable oceanic settlement 25 years on.
Copyright and Artificial Intelligence
Government report and back track on copyright opt out for AI training but no clear preferred alternative as yet.
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.
Inspiration for a new 2026 wave of Irish construction professionals.
New planning reforms and Warm Homes Bill
Take centre stage at UK Construction Week London.