Warm And Cold Roofs: What Are The Differences?

Flat roofs come in a different range of materials from felt, to rubber, to fibreglass. For most people this is where the level of variety ends, among contractors there is a deeper level of variation – ‘cold’ roofs and ‘warm’ roofs. In a self-explanatory way, warm roofs and cold roofs refer to the style of insulation that is installed onto a flat roof and how effectively the roof is insulated as a result. With winter on its way we thought we would explain to our customers the differences between the two and why we always recommended a warm roof over a cold one. What are cold roofs and warm roofs? A cold roof is a very early form of flat roof that was made before consideration for insulation was introduced. Cold roofs consist of a structural timber deck with a waterproof covering applied to the top of the deck, sometimes without insulation as this was an afterthought at the time, which is what makes them ‘cold’. A warm roof describes the best current form of flat roof used today. They are designed and made to be suitable over all types of room, including bathrooms and kitchens. Unlike cold roofs, insulation was incorporated into their design, meaning it is always used and done so more effectively and efficiently. How did people keep warm with a cold roof? To help keep a room with a cold roof warm insulation would be used, but it is different to modern warm roofs. Insulation was added in the form of a mineral wool which was placed between the timber rafters. However, because the roof is a ‘cold’ roof, condensation could occur if warm air trapped by the insulation came into contact with it. Should condensation occur it could damage the decking and/or timbers, internal ventilation gaps were added between the insulation and the roof deck to reduce this, but as this may not have been enough external ventilation was often added too. Unfortunately this often led to a great deal of heat loss, making them even less efficient despite using insulation. Why are warm roofs better for most rooms? For warm roofs, the insulation was moved from the rafters to the outside of the roof’s structure, bringing the roof deck ‘inside’. With the insulation on top of the roof deck and a high performance roofing system on top of that, condensation cannot occur on the underside of the deck – this means there is no risks of damp conditions and rot. No condensation means that no external ventilation is required either and no heat will be unintentionally lost through it, resulting in a much warmer room than if a cold roof had been used. This allows you save money on your heating bills and create a much more energy efficient home. Our roofing systems All of the warm roofing systems that we install meet modern thermal, acoustic and fire standards, providing long term roofing solutions that will last in excess of 30 years. We are also registered with Competent Roofer and many other roofing contractor accreditors, so you can ensure we will provide a reliable and trustworthy service. For more information on warm and cold roofing, or to answer any other roofing questions that you may have, feel free to contact us on 01603 418818 or send us an email to enquiries@roofsuk.co.uk.