Solutions: Multi Foil PhotonAir - Over Rafter
| Application | Rafter | Uvalue | Draped | Counter batten |
| Social & Private housing roof |
400 | 0.18 | 160mm Glass | 120mm PIR |
| 600 | 150mm Glass | 100mm PIR | ||
| Historic & Public buildings roof |
400 | 0.32 | 50mm PIR | |
| 0.60 | No additional | |||
| 600 | 0.30 | 50mm PIR | ||
| 0.59 | No additional | |||
| Barn conversion roof exposed rafters |
400 | 0.18 | 80mm PIR | 110mm PIR |
| 600 | 75mm PIR | 95mm PIR | ||
| New build & extensions roof |
400 | 0.16 | 190mm Glass | 140mm PIR |
| 600 | 170mm Glass | 120mm PIR | ||
| Contact us for bespoke solutions | ||||
What is Over Rafter Roof Insulation?
Over rafter roof insulation is installed above the rafters rather than between or below them, creating a continuous thermal layer across the roof structure.
Multi foil solutions such as PhotonAir are designed for a wide range of roofing applications, including new builds, extensions, and re roofing projects.
Manufactured using woven glass and aluminium low emissivity outer layers with an insulating core, these systems help reduce heat transfer while maintaining a slim and practical roof build up suitable for both residential and commercial properties.
Multi Foil Solutions for a Range of Roof Types
Over rafter multi foil insulation is ideal for social and private housing roofs, offering a practical way to improve thermal performance without significantly increasing roof depth.
It is also well suited to historic and public buildings, where maintaining internal character and structural integrity is essential. In barn conversions, the slim profile helps preserve exposed beams and vaulted ceilings, while in new build homes and extensions it supports modern energy efficiency standards.
With A1 non combustible options available to BS EN13501-1, these systems provide reassurance for projects where fire performance is a key consideration.
Benefits of Over Rafter Multi Foil Insulation
The primary benefit of over rafter multi foil insulation is the creation of a continuous insulation layer that helps minimise thermal bridging through the rafters.
Products within the A1 non combustible range, including reflective breather membranes and vapour control layers, provide enhanced fire safety performance comparable to materials such as stone wool and concrete.
In addition, these systems can contribute to improved airtightness and moisture management when correctly installed, helping to reduce energy loss, improve occupant comfort and support compliance with modern building regulations across a wide range of roof types.