Cold Roof Ventilation Gap

In a cold climate the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditioned.

Cold roof ventilation gap.

For both a warm and cold flat roof a vapour control layer must be installed. Ventilation is required for these roofs. 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. The air gap dimensions shown on the drawings are the minimum widths required for clear continuous ventilation air paths at the eaves.

Large cold pitched roof voids can be used to locate services such as water storage tanks associated pipes ventilation ducts electrical cables and recessed light fittings. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. In this way the roof itself is kept cold. In order to keep the integrity of the roof it is recommended to install vmzinc breather membrane on the cold side of the insulation and a vapour control layer adapted to the internal humidity load of the building on the warm side of the insulation.

Condensation encourages rot and mould growth. Intake vents located at the lowest part of the roof under the eaves allow cool. A cold roof is where all of the insulation is placed either between and under or completely under the joists or deck. Ventilation is not needed in a warm roof.

Where this is the case all gaps and holes around service that pass into the cold roof via the ceiling should be sealed to restrict the amount of water vapour that. Building regulations state that a ventilation gap of at least 50mm must be in place between the insulation and the underside of the flat roof deck. Introduction warm cold roofs this guidance offers guidance on the difference benefits between warm and cold roofs. The intent of roof venting varies depending on climate but it is the same if you re venting the entire attic or if you re venting only the roof deck.

No insulation is on top. You only need ventilation in a cold roof. Continuous ventilation openings are made at the top and bottom. Ventilation at the eaves.