Cold Flat Roof Insulation Between Joists

No ventilation is required for these types of roofs.

Cold flat roof insulation between 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. The insulation is below the deck but above the plasterboard. 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. As for insulating below the joists an insulating laminate insulation bonded to plasterboard such as celotex pl4000 or a separate rigid pir insulation board finished with a separate sheet of plasterboard can be securely fixed to the joists to provide an internal finish to the roof.

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. This is used for refurbishment e g. Refurbishing an existing timber joisted flat roof which has no insulation. A warm deck roof is where the insulation is placed on top of the rafters joists and the roof covering is then placed over the insulation.

We ve watched your video on youtube and wonder if you could give us some advice please. This method of insulation can also be used to upgrade the thermal performance of an existing roof without affecting the waterproofing system. Tlx silver can be used to reduce the thickness of additional insulation required between the joists to help ensure a ventilated gap is maintained between the insulation and the 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.

Last year we bought a barn that was converted in the 1980 s. Poly to the underside of joists. Roof insulation between joist. Great videos thanks for sharing.

Many properties use this option as there are no additional costs for scaffolding or organising how to gain safe access to the roof exterior. A cold flat roof is one where the insulation is between or between and below the roof joists. Flat roof dormer the traditional cold deck flat roof system is to install the insulation between and under the joists with ventilation below the timber deck. The insulation material is placed between the supporting joists leaving a gap of 50 60mm between the roof and insulation.

A cold flat roof is defined by insulation being installed between and if necessary underneath the timber joists.