Hot Roof Vs Cold 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.

Hot roof vs cold roof.

Hot roofs act as a thermal break and will prevent ice dams from forming on the roof during winter months. You create a warm roof or a cold roof simply by applying the layers of the roof in a different order. In climates that remain cold for a sustained period unvented roofs can cause more harm than good. Namely the insulation layers.

So what kind of difference does this make. The hot roof assembly is found almost exclusively in new construction. That is the deciding factor. A little q a on the subject i tapped sean from alabama green building solutions to help clear up a few lingering questions i had about hot roofs and cool roofs.

Cold roof construction requires that a suitable ventilated air space exists above the insulation layer within which the air is constantly mobile being replenished by fresh incoming air whilst the air resident within the void space is being expelled via a natural vent action at another point. A warm roof is much more straightforward to install and provides a superior thermal performance and is therefore more costly. In cold roofs the outside air is allowed to freely flow under the roof sheathing. In a cold roof the insulation is applied between the rafters but in a warm roof the insulation is applied on top of the existing roof surface.

Thus your unventilated roof is indeed a hot roof. 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.