This flat roof in west Wales needed proper ventilation to resolve moisture build up, a common problem for cold roofs (explained here in relation to warm roofing) especially in such notoriously rainy areas of the UK.
Cold roofs are not really "cold". In cold roofing, as can be seen in the photos, insulation is laid between joists with space left for ventilation, which allows moist air to escape rather than forming condensation and ultimately mould and damp. As such, these roofs simply have an overall lower U value (a measure of heat retention), losing heat more quickly than "warm roofs". However, they have a lower profile and can work out much cheaper provided ventilation is properly conceived.
In this case the 50mm gap left for airflow is clearly visible in the above photographs, as is the staged laying of the insulation and finishing materials. The end roof should now last for many years without condensation issues whilst still providing a well insulated space.
To find out more about cold roofing or flat roofing simply follow the links around the site. Alternatively feel free to email us (we don't chase, aim to respond within 24 hrs and never pass on your details) or call us on 01970 610047