How to Fit SuperQuilt Under Roof Rafters

This step-by-step guide will show you how to install YBS SuperQuilt beneath the rafters of a pitched roof.

SuperQuilt is a high performance multifoil insulation designed for use in roofs, walls and floors. Its flexible 19 layer construction makes it quick and easy to install, while helping reduce heat loss without taking up the space required by thick rigid insulation.

When fully taped and sealed using ThermaSeal Foil Tape, SuperQuilt also acts as a high performing vapour control layer, helping create a continuous airtight insulation layer across the roof.

Before You Begin

Inspect the roof for any leaks, damp or damaged timbers before installing SuperQuilt and complete any necessary repairs first.

If a non breathable roofing felt is present, we recommend using lap vents. Do not block existing ventilation openings and always maintain the required clearances around electrical equipment, recessed lighting and other heat producing appliances.

Measure and Cut the First Length

Roll out the SuperQuilt and measure the length required for your first section. Mark the insulation and cut it to size using Multifoil Insulation Scissors or a suitable cutting knife.

SuperQuilt can be installed horizontally or vertically across the rafters depending on the shape and size of your roof space.

Staple SuperQuilt Beneath the Rafters

Position the SuperQuilt beneath the rafters and pull it taut. Secure to each rafter using 14mm staples at approximately 300mm intervals. 

Keeping the insulation taut helps create a neat, continuous layer while allowing the SuperQuilt to expand into the air cavities.

Install the Next Section and Overlap

Measure and cut your next section of SuperQuilt before fixing it alongside the first. Overlap adjoining sections by a minimum of 50mm and continue stapling the insulation securely to the rafters.

Maintain the 50mm overlap across all horizontal and vertical joints.

Tape and Seal the SuperQuilt

Tape and seal all 50mm overlaps and perimeter edges using ThermaSeal Foil Tape. At the eaves, cut around the rafters and seal securely to maintain a continuous vapour control layer.

Continue Across the Rafters

Continue measuring, cutting, stapling and sealing the SuperQuilt until the entire underside of the roof is covered.

Carefully cut around structural timbers and other obstacles, ensuring there are no exposed gaps within the insulation layer.

Install Counter Battens and Internal Finish

If finishing with plasterboard, fix minimum 25mm counter battens through the SuperQuilt and into the rafters using Multifoil Screws, then secure the plasterboard or chosen internal finish to the battens.

Want Even Greater Thermal Performance?

For projects requiring greater thermal performance, additional insulation or a second layer of SuperQuilt can be incorporated into the roof build-up.

For a two layer SuperQuilt installation, the first layer can be recessed between the rafters before installing a second continuous layer beneath the rafters. Both layers should be overlapped by a minimum of 50mm and fully taped and sealed.

The exact build-up required will depend on your existing roof construction and target U-value. Use our online U-Value Calculator to check the expected thermal performance and recommended insulation build-up for your project.

Any questions at all, just get in touch. You can submit an enquiry or request a call back and our team will be happy to help.

Disclaimer – Ecohome-Insulation cannot be held responsible for any losses financially or physically from advice provided in this How-To-Guide.

Installation of SuperQuilt Insulation for under rafter should be in harmony with the official certificate. Recommended fixing materials and good building practice should also be used.