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.
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.
Install quinn term ql kraft insulation boards below the joists using suitable mechanical fixings.
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.
How to install insulation in a flat roof with timber deck insulated between and below joist.
The majority of domestic cold flat roofs use insulation between and under the joists.
Ventilation is required for these roofs.
Poly to the underside of joists.
A cold deck flat roof will typically require insulation to be installed between the roof joists to comply with building regulation requirements.
It is preferred to have the bulk of the insulation between the joists to reduce any risk of condensation.
Refurbishing an existing timber joisted flat roof which has no insulation.
Colde deck insulation 1.
The insulation is below the deck but above the plasterboard.
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.
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.
To form a vapour control layer seal the joists between the boards.