Flat Roof Insulation Above And Between Joists

The following images provide examples of flat roof details.

Flat roof insulation above and between joists.

Parapet detail masonry cavity wall flat roof with parapet insulation. Alternatively battens can be secured to the underside of the. The roof itself is therefore kept warm. Here the roof deck is maintained at the same temperature as the internal conditions hence warm deck roof.

Flat roof detail masonry cavity wall flat roof insulation above and between joists. Bs 5250 2011 the british standard for the control of condensation in buildings does not recommend installing insulation between timber joists as well as above the deck. 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. Warm deck insulation 1.

A cold flat roof is defined by insulation being installed between and if necessary underneath the timber joists. How to install insulation in a flat roof with timber deck insulated above the joists. Set the quinn therm qrfr ply insulation boards onto a wide 30mm bead of vapour resistant sealant applied to the upper surface of all the joists and cross noggins. 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.

Here the roof deck is maintained at the. The loft space can be used as a habitable room. Celotex polyisocyanurate pir foam insulation boards are easy to cut and handle. The insulation is below the deck but above the plasterboard.

This is used for refurbishment e g. Good question theoretically when building a warm roof the vaper control layer goes on the warm side of the insulation. An over and between rafter insulation solution can be a feature of a new build project. Refurbishing an existing timber joisted flat roof which has no insulation.

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. A cold flat roof is one where the insulation is between or between and below the roof joists. A warm flat roof is defined by insulation being installed on top of the roof deck. Flat roof detail masonry cavity wall flat roof insulation above and between joists.

It is also suitable for retrofit with a substantial renovation of the roof. A warm roof is defined as being when the all or the majority of the insulation is above the joists or deck.