Cold Deck Roof Insulation

Polyisocyanurate thermal insulation also referred to as polyiso pir or iso is a popular low slope commercial building roof insulation.

Cold deck roof insulation.

Rigid insulation used to control condensing surface temperatures rigid insulation installed above roof deck. Warm roof insulation ensures the entire roof structure is insulated meaning a warm deck roof is more energy efficient than a cold roof. Where insulation depth is restricted by the flat roof construction it may be necessary to install the roof insulation between and below the joists to create a cold deck structure. This method of insulation can also be used to upgrade the thermal performance of an existing roof without affecting the waterproofing system.

A cold roof has the insulation placed below the structural deck which thus remains cold. The breakdown warm roof vs cold roof. In cold and very cold climates selecting a roof deck condensing surface temperature criteria of 45 f is very conservative. If spray foam is used a vent space may still be needed directly under the roof deck.

Care should be taken with these assemblies particularly in cold climate zone locations i e. Introduction warm cold roofs this guidance offers guidance on the difference benefits between warm and cold roofs. During cooler night times and in winter periods the deck temperature can then be below the dew point of the interior air. Hence the term cold decks construction materials wood based products absorb moisture.

Zones 5 6 7 and 8 in that the manufacturers of these materials assume that roof deck may require ventilation to assist drying. It can also be used as a roofing cover board and in building envelope applications. A cold flat roof insulation requires more work taking off old boards and replacing them and the roof surface. The roof deck is cold wood decks without insulation above them will readily equilibrate to the exterior temperature.

Cold deck roof a cold deck roof is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof. Cold roof sheathing is one of many components in keeping ice dams at bay. Ratio of r value between rigid insulation and batt insulation is climate dependent. To create a cold roof we provide each rafter bay with a full width vent chute that leaves a 1 1 2 inch air channel under the roof deck.

The second and nearly as important goal is to keep the roof deck as cold as possible during upstate new york winter months. Ventilation is required for these roofs.