Warm Deck Flat Roof Ventilation

For a simple duo pitch roof bs 5250 specifies sufficient ventilation as being.

Warm deck flat roof ventilation.

25mm at eaves on each slope and 5mm at ridge. In flat roof construction thermal insulation can be placed above and below the structural roof deck or waterproofing layer. Ventilation is required to the underside of the deck. If ridge or eaves ventilation is not possible ventilation tiles can be used at high or low level to achieve the required airflow.

In a warm flat roof construction the insulation is positioned above the structural deck and no ventilation is required. When placed below the structural deck. Adequate ventilation must be provided between the insulation and the underside of the roof deck to prevent the risk of interstitial condensation forming within the void area. Thickness varies according to the manufacturer s specifications.

The roof itself is therefore kept warm. Flat roof ventilation allows for the circulation of air in the property particularly for warmer rooms in residential buildings. Flat roof u value 0 18 w m2k 2 warm deck flat roof the type of insulation for this is usually of a rigid type and the thickness will vary depending on the manufacturer s specifications. Warm roof ventilation specification.

When thermal insulation is placed below the deck the ventilation must. There are two types of flat roof systems warm and cold roofs which affect the positioning of the ventilation. This cold deck construction is considered problematic in the humid temperate climate of the uk where the effective. Ventilation is not needed in a warm roof.

Cold deck this is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof. This is placed over the roof joists and a board normally external ply is laid on top. By majority the rule of thumb is that in a domestic house not flats approximately a third of the total thermal performance of insulation can be placed below the deck with two thirds above the deck sometimes this is called a hybrid warm roof. What is flat roof ventilation.

For guidance on roof insulation please contact us on 44 01257 488 000. Ventilation is required for these roofs. Find warm flat roof cold flat roof insulation solutions at iko polymeric.