Flat Roof With Exposed Rafters Insulation

The insulation for exposed rafters is installed on the exterior side of the finish ceiling.

Flat roof with exposed rafters insulation.

In the case of a cold roof structure the insulation is placed between or between and under the rafters or at ceiling joist level and the roof is ventilated by leaving a 50mm gap above the insulation which vents air to the outside. Insulation between the rafters can be designed in two ways. If moisture is a major concern you can also install xps rigid insulation which offers superior moisture resistance. Breathing roof with low resistance lr underlay with this option insulation fully fills the rafter space without an airspace between the insulation and type lr underlay.

On top of your roll roofing add several layers of comfortboard rockwool. You can expect to pay about 55 100 sq ft. Images courtesy simpson gumpertz heger. Isoboard thermal insulation fitted as a ceiling following the roofline allowing the opportunity to create additional space or a liveable loft conversion.

Warm roof fixings secure insulation above rafters. I ve been toying with this idea for flat roof insulation which will be a bit more expensive but avoids foam of any kind. It is top quality and the most cost effective product for your flat roof. While expensive the best insulation is polyiso rigid foam.

Safety precautions and mistakes to avoid during garage roof insulation. The levelling tool enables. Insulation boards are sandwiched between rafter and counterbatten that are connected with super 7 roof fixings. Resistance to compression 943 psf osb and then some more roofing.

For a 1 inch board equivalent of 6 r value. Hack n stack sealed foam board between the rafters would be better since it s at least an air impermeable insulation but even that would require a vent gap below the roof deck to meet code and you d still be under r38 on that 2x6 rafters unless you fattened it out per holladay s recommendation. This is often a layer of tongue and groove boards nailed to the exterior side of the exposed rafters.