Cold Deck Roof Insulation

Cold roof sheathing is one of many components in keeping ice dams at bay.

Cold deck roof insulation.

During cooler night times and in winter periods the deck temperature can then be below the dew point of the interior air. This construction relies on a vapour control layer working effectively and in tandem with a continuous ventilated airspace to disperse the water vapour to atmosphere before it reaches the cold deck and condenses. 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.

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. Polyisocyanurate thermal insulation also referred to as polyiso pir or iso is a popular low slope commercial building roof insulation. A cold roof has the insulation placed below the structural deck which thus remains cold. If spray foam is used a vent space may still be needed directly under the roof deck.

A cold flat roof insulation requires more work taking off old boards and replacing them and the roof surface. The second and nearly as important goal is to keep the roof deck as cold as possible during upstate new york winter months. Warm roof insulation ensures the entire roof structure is insulated meaning a warm deck roof is more energy efficient than a cold roof. This method of insulation can also be used to upgrade the thermal performance of an existing roof without affecting the waterproofing system.

Introduction warm cold roofs this guidance offers guidance on the difference benefits between warm and cold roofs. It can also be used as a roofing cover board and in building envelope applications. Zones 5 6 7 and 8 in that the manufacturers of these materials assume that roof deck may require ventilation to assist drying. Rigid insulation used to control condensing surface temperatures rigid insulation installed above roof deck.

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. It is a thermoset closed cell foam that is an optimal insulation solution for low slope roofs. Care should be taken with these assemblies particularly in cold climate zone locations i e. In cold and very cold climates selecting a roof deck condensing surface temperature criteria of 45 f is very conservative.

The roof deck is cold wood decks without insulation above them will readily equilibrate to the exterior temperature. Guidance advice on.