Passive 350 features a 300mm twin wall sheeted on both sides with 9mm OSB, with a membrane on the inside forming the airtight layer.The build-up features a 140mm cellulose-insulated stud, a 53mm thermal break, and a second 89mm insulated stud which is designed to be thermal bridge free. Passive 350 achieves a U-value of 0.13, but this can be increased or reduced by altering the dimensions of the thermal break.
To get this certification, we had to ensure that everything materials, detail design and factory quality control standards were to the highest level. Four key factors had to be addressed: U-values, airtightness, thermal bridging, and interior surface temperatures. The fact that Passive 350 is certified will reduce the cost of building passive. Because all the information on this system is now included in PHPP version 8.5, a PHPP designer can literally choose the Cygnum system from dropdowns and avoid having to reinvent the wheel with a lot of initial design work. Their workload is less, and the quality is assured. The system is suitable for everything from large non-domestic projects to one-off passive houses.
Cork-based Cygnum has already built two passive house certified schools in the UK and is currently working on more. The company is building a new passive house archive and records centre for Herefordshire Council and will start work later this summer on another passive building at the University of East Anglia.