Cold Roof Insulation Between Joists

Cold roof a cold flat roof is one where the insulation is between or between and below the roof joists.

Cold roof insulation between joists. A cold deck flat roof will typically require insulation to be installed between the roof joists to comply with building regulation requirements. Unless the joists are exceptionally deep there is also likely to be a requirement to install insulation to the underside of the joists as the upper 50mm of joist space is usually required to be left clear for ventilation purposes. This quetion is to do with warm roofs and cold roofs presumably the 50mm of insulation on the underside of joists would act as the vapour barrier if taped sealed correctly or if insulation between joists a vapour barrier i e. Refurbishing an existing timber joisted flat roof which has no insulation.

The insulation is below the deck but above the plasterboard. How to install insulation in a flat roof with timber deck insulated between and below joist. 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. Poly to the underside of joists.

Colde deck insulation 1. Insulation between the joists keeps warmth in your living space below and creates a cold loft while insulation in the rafters allows you to keep warmth in the roof space as well. To form a vapour control layer seal the joists between the boards. Install quinn term ql kraft insulation boards below the joists using suitable mechanical fixings.

The majority of domestic cold flat roofs use insulation between and under the joists. The rule of thumb for foil faced boards like thermapitch tp10 or kooltherm k7 in this scenario is that you can have no more insulation under the joists than you have between the joists. Ventilation is required for these roofs.