Warm Roofs

What Is A Warm Flat Roof?

Warm roof construction is an efficient roofing method in which the insulation layer is installed on an Air and Vapour Control Layer (AVCL) over decking above the structural timbers of a roof. The key point to understand about this construction is that the AVCL is always fitted on what’s called the warm side of the roof, i.e., the underside of the insulation. Everything under the AVCL is warm because it’s shielded by the insulation from the cold outside. Not only that, everything under the AVCL is deemed to be internal and subject to internal temperature and humidity changes. What Is A Warm Flat Roof? The installation of a warm roof offers substantial thermal insulation benefits, contributing to a more consistent internal temperature throughout the property and potentially reducing heating costs. The method of construction is robust and straightforward. There are several advantages to opting for a warm flat roof. Economically, it can be more cost-effective, as the construction work is executed entirely above the roof joists, avoiding the need for more complex, invasive, and labour-intensive installation methods. The continuous layer of insulation also reduces thermal bridging, leading to a more energy-efficient building. Additionally, because all components are installed above the roof joists, [...]


Tucking in your roof

How to tuck in your roof correctly. “Tucking in your roof” is a term coined by @steveroofer in 2010, and it serves as a powerful metaphor for the meticulous process of insulating a roof to ensure optimal performance. Just as one would tuck in the edges of a warm blanket for a snug night’s sleep, the same principle applies to roofing insulation. When @steveroofer introduced this term, he was emphasising the crucial importance of sealing and insulating a roof properly. It’s not just about the quality of the insulation material; it’s about the attention to detail in making sure there are no gaps or openings that could allow drafts to compromise the thermal efficiency of your roof. Imagine your roof as a cosy quilt and the insulation as the warm filling. To truly benefit from its thermal properties, you must tuck in every edge and corner, just like you would with a blanket on a chilly night. This means meticulously sealing gaps, insulating vulnerable areas, and ensuring that the insulation forms a snug barrier against the elements. In a video on YouTube, @steveroofer demonstrated how to implement this concept practically, particularly when insulating behind the front fascia to form a warm roof. By tucking in the insulation [...]


Lead roof venting

A customer asks about venting a lead roof Spired on by my Youtube vide Lead Roof Venting Lead is beautiful & cross venting vital for a cold deck roofs. Warm deck usually avoids the need for cross venting but I notice that the LSA & other lead sheet groups recommend cross venting even a warm deck flat roof where this should be unnecessary for a warm deck roof. What is your opinion on providing yet another set of counter battens & decking on top pf a warm deck roof when lead sheeting is applied rather them single ply? Have you ever seen or experienced internal sweating of a lead sheeted warm deck roof? Is it an over precaution when using lead? What is your view from the sharp end? Surely if the visqueen FB vapour barrier is applied well under the insulation & sealed to all the abutments, cross venting the top side of a warm deck roof should be totally unnecessary. REPLY The perfect flat roof is a warm deck roof with a cold vented roof over the top. The cold vented roof allows any moister that gets past the warm roof to escape basically you are building in redundancy into the [...]