Kingspan Flat Roof Insulation Between Joists

A warm flat roof known as a cold flat roof in other parts of the world is one where the insulation is between or between and below the joists of the roof.

Kingspan flat roof insulation between joists.

A cold flat roof is one where the insulation is between or between and below the roof joists. With a thermal conductivities as low as 0 024 w mk it is used to insulate flat roofs waterproofed with fully adhered single ply partially bonded built up felt mastic asphalt and cold liquid applied waterproofing. The insulation is below the deck but above the plasterboard. It is important to make sure that there is at least 50 mm airgap.

We ve watched your video on youtube and wonder if you could give us some advice please. Kingspan thermaroof tr27 is a high performance insulation with a fibre free rigid thermoset polyisocyanurate pir core. The underside of the rafters in this case will need to be finished with a suitable vapour control layer vcl and plasterboard to provide a suitable internal finish to the roof. Roof insulation between joist.

Alternatively battens can be secured to the underside of the joists and gmw fitted between these in much the same way as between the main roof joists. It is preferred to have the bulk of the insulation between the. 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. This can be difficult because of the angle of pitch of the roof and the position of the rafters can prevent the insulation laid over the joists from.

This is used for refurbishment e g. In this blog post we will be looking at insulating pitched roofs and why putting insulation just between the rafters isn t a viable solution. It already has foil backed insulation in the roof but only 35mm and we would like to increase this without taking the roof off as it s simply too expensive. The majority of domestic cold flat roofs use insulation between and under the joists.

When insulating at ceiling level in a pitched roof with loft insulation between and over joists it is vital to ensure the continuity of insulation at the specified r value right to the eaves. It allows insulation to be added without having to replace the waterproofing on the existing roof or raising the roofline. We also have insulation boards suitable for more specialist roof applications for example inverted roof insulation and balcony insulation. The general advice we give is that you should always insulate between and above the rafters or between and under the rafters on our u value calculator we don t give an option for putting insulation between the rafters.