The recognised flat roof build ups for best design practices are.
Which is best warm or cold roof.
The object being to design out the possibility of warm moisture laden air coming into contact with a cold surface and condensing.
However it must be pointed out that a cold roof requires more work and isn t as thermally efficient as a warm one.
A warm roof is much easier to install offers great thermal performance and can also add height to the flat roof.
Basically the term cold roof refers to a traditional roof or vented roof while hot roof refers to a roof that is not ventilated and which has foam insulation attached directly to the roof sheathing.
Warm roof insulation ensures the entire roof structure is insulated meaning a warm deck roof is more energy efficient than a cold roof.
Warm roof construction requires that the entire roof construction is encapsulated within the insulation envelope of the building to be kept warm.
The breakdown warm roof vs cold roof a cold flat roof insulation requires more work taking off old boards and replacing them and the roof surface.
The membrane is then attached to the insulation.
There are pros and cons to both a warm roof and a cold roof.
This process offers a greater level of thermal insulation for your whole property.
The reason for this is because an unvented roof allows more opportunity for conditioned air from the home to permeate the insulation warming the roof deck and causing ice dams during the winter.
A cold roof is best when you re initially creating a flat roof and is cheaper than a warm roof but does provide an inferior thermal performance.
This is because the insulation is laid over the top of the roof deck on top of a vapour control layer and underneath the roof covering.
In contrast a warm roof is one designed to keep the entire roof structure warm.
A warm roof construction has many benefits over a traditional cold roof essentially it is a breathable roof construction which allows moisture to escape which in turn prevents damp and any associated decay problems.
A warm roof construction allows heat to be conserved within a property without the need for a ventilation system.
A warm roof is much more straightforward to install and provides a superior thermal performance and is therefore more costly.
In climates that remain cold for a sustained period unvented roofs can cause more harm than good.