Warm-Roof flat roofs are becoming a popular choice for people looking for energy efficient solutions. Whilst cold-roof designs are the more traditional types of roofing you may expect, a flat roof with a warm-roof will help by reducing the risk of condensation.
This is accomplished by moving the ‘dew point’ to the outer side of the roof structure. Although investing in a warm-roof may seem costly, the long term reduction in cooling and heating costs will pay for the initial cost. Regardless of the costing the occupier can look forward to a more comfortable environment whether winter or summer.
Cold Roof flat roofs – The Traditional flat roof design
Flat roofs were originally constructed using a timber structure that was coated in a covering that is waterproof. This design has been used over many years when energy efficiency was not a priority. Although a flat roof that is cold will have some form of insulation it is normally constructed using a mineral wool that is packed between the timbers or joists. The only requirement was a minimum of 50mm (2 inches) air gap which was left between the roof deck and the insulation.
The gap works by allowing air-flow to modulate the warm and moist air. This warm air would then escape instead of coming into interaction with the ‘cold roof’ which will cause condensation. Condensation may cause rotten decking and damp ceilings and insulation and the timbers. Condensation would also cause the structure to become less efficient, especially if the insulation became damp.
The external ventilation system is important as it would also reduce the amount of condensation that can be found in a cold roof. External ventilation is aided by using soffit vents on the undersides of fascia boards. Sadly many of the traditional cold roofs were then built without the provision of soffits, so instead it is common to see unsightly ‘mushroom vents’ on the tops of roofs or vents fixed incorrectly to fascia boards.
The key to good ventilation is to allow the condensation to escape; especially for roofs on kitchens and bathrooms. While good ventilation is important to reduce the risk of condensation, its effect can mean a large amount of lost heat.
Warm Roof flat roof – Revolutionizing Roofs
The simple but effective redesign of flat roofs brought the structure ‘inside’ resulting in a ‘warm roof’. This was created by placing the insulation on the outer side of the building which helped reduce the likelihood of the formation of condensation and helped reduce damp. This strategy works by heat conservation so that ventilation is not required.
The use of modern materials such as polyisocyanurate or PIR is a rigid foam insulation rather than the traditional wool insulation. PIR has reflective foam on both sides and provides double the amount of heat efficiency whilst not being limited to the timber joist or rafters depths. This is a vital component for a warm roof structure.
If you already have a flat roof that is a cold roof; an addition of County Flat Roofing may convert it easily to a warm roof flat roof. If a cold flat roof is converted before any condensation or damp problems occur the insulation can be fixed straight on top. This will allow the felt to become a barrier for vapor.
The whole conversion is complete with a waterproof covering that is high performance, such as Sarnafil which is certified and recognized by the British Board of Aggrement with a recognition that Sarnafil will last for at least 40 years. Investing in this added protection will continue to pay disbursements in the future and will pay for itself over and over.