Project Type:

New Build

Sq. Meterage:

Warm Roof 275

Main Contractor:

Maxi Construction


New build Passive Haus two storey extensions building to Primary School, constructed from cross laminated timber frame and roof deck. Scaffolding hoisting and access provided by the main contractor.

Roof specification

Warm roof construction of Sarnafil single ply roofing system comprising Sikabit VB SA-724 self-adhesive vapour control layer, 405mm Sikatherm MW DD mineral wool thermal insulation, laid in three layers and mechanically fixed by means of stainless steel sleeved anchors, all waterproofed with Sarnafil G410-18 EL in lead grey finish, bonded with Sarnacol 2170 adhesive.


This project required the highest quality of flat roofing specification and installation to meet the demanding standards imposed by Passive Haus.

Passive Haus standard aims to provide a high level of comfort using the minimum energy, thereby promoting better health and wellbeing and work performance for the building occupants. To achieve this, a high standard of workmanship and quality control is essential throughout the entire construction of the building.

The project was done during the coldest and wettest months of the year which added to the complications of meeting the demands for air-tightness, insulation, the avoidance of cold bridging and water-tightness. The understated finished installation conceals considerable technical involvement and emphasises the installation skills, all of which results in a high quality-controlled expert construction which meets full Passive Haus demands and compliance with a 25 year guarantee from Sarnafil.

Project Gallery

Click any image to enlarge