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
Local leaders gain new powers to support local high streets
High Street Rental Auctions to be introduced from December.
Infrastructure sector posts second gain for October
With a boost for housebuilder and commercial developer contract awards.
Sustainable construction design teams survey
Shaping the Future of Sustainable Design: Your Voice Matters.
COP29; impacts of construction and updates
Amid criticism, open letters and calls for reform.
The properties of conservation rooflights
Things to consider when choosing the right product.
Adapting to meet changing needs.
London Build: A festival of construction
Co-located with the London Build Fire & Security Expo.
Tasked with locating groups of 10,000 homes with opportunity.
Delivering radical reform in the UK energy market
What are the benefits, barriers and underlying principles.
Information Management Initiative IMI
Building sector-transforming capabilities in emerging technologies.
Recent study of UK households reveals chilling home truths
Poor insulation, EPC knowledge and lack of understanding as to what retrofit might offer.
Embodied Carbon in the Built Environment
Overview, regulations, detail calculations and much more.
Why the construction sector must embrace workplace mental health support
Let’s talk; more importantly now, than ever.
Ensuring the trustworthiness of AI systems
A key growth area, including impacts for construction.
Foundations for the Future: A new model for social housing
To create a social housing pipeline, that reduces the need for continuous government funding.
Mutual Investment Models or MIMs
PPP or PFI, enhanced for public interest by the Welsh Government.
Key points and relevance to construction of meeting, due to reconvene.