Flat Roof Insulation Between And Under Joists

Energy assessments by celotex.

Flat roof insulation between and under joists.

Between and over rafters. Alternatively battens can be secured to the underside of the. A cold flat roof is defined by insulation being installed between and if necessary underneath the timber joists. The full version allows any size.

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. Refurbishing an existing timber joisted flat roof which has no insulation. 1 enter joist details 1 1 span and joist spacing. 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.

I ve built a timber frame to support a new plasterboard ceiling below the existing one. Good question theoretically when building a warm roof the vaper control layer goes on the warm side of the insulation. This method of insulation can also be used to upgrade the thermal performance of an existing roof without affecting the waterproofing system. A warm flat roof is defined by insulation being installed on top of the roof deck.

I intend to fill between my joists with foil backed insulation board 75mm with a thin layer of insulation on top of the joists. Flat roof with asphalt finish with felt boarding insulation. Between and under joists. A cold flat roof is one where the insulation is between or between and below the roof joists.

Here the roof deck is maintained at the same temperature as the internal conditions hence warm deck roof. Flat roof joist calculator. Between and under rafters. This is used for refurbishment e g.

If you put insulation under the decking and between the joists you lower the temperature of the decking and lower the due point thus bringing it closer to the danger point of being in the building. It is preferred to have the bulk of the insulation between the. The majority of domestic cold flat roofs use insulation between and under the joists. Here the roof deck is maintained at the.

Technical services online u value calculator. The insulation is below the deck but above the plasterboard.