From School, to College, to Apartments
The former Morley School in Leeds was built in 1870 and served the community first as a school. Then, it became an FE college which subsequently became part of Leeds City College. When this part of the college closed, the solid stone building was offered for redevelopment and now houses 28 apartments.
Working with shallow rafter depths
With only 75mm deep rafters, the best solution was to drape TLX Gold into the rafter. The plan was to run 50mm of PIR below rafters, preserving sufficient headroom. This achieved a U-value of 0.26 W/m²K.
They could accommodate another 25mm of PIR at the bottom of the rafters. (Given that TLX Gold plus a minimum unventilated heat-reflecting air gap requires 50mm). However, where there are two thicknesses of PIR adjacent, the thicker one should always be on the colder side in order to avoid condensation at the interface between them. Also, the unventilated space between the low emissivity underside of the TLX Gold and the PIR reflects heat and contributes to the thermal performance.
The problem: Finding the best way to insulate a Victorian roof with 75mm rafters to achieve a satisfactory U-value without compromising headroom.
The solution: TLX Gold: the insulating breather membrane with a low emissivity surface that makes use of unventilated air spaces in a limited rafter depth to contribute to the thermal value.
