Super insulation – step 1
The first aspect of implementing a Passivhaus design that differs from standard UK construction is the amount of insulation that must be incorporated into the building envelope. Up to 300 mm, and sometimes more, is common in Passivhaus buildings. This will require familiarisation with potentially new forms of construction such as externally insulated solid masonry walls, or with new details such as the installation of windows into 30 0mm cavities.
Construction of junctions will also differ from the current generation of buildings in order to accommodate this thickness of insulation. For example, trussed rafters are likely to have up stands to ensure the full thickness of insulation can be carried right into the eaves. These details and the method of fixing the
insulation must be determined before the commencement of work on site.
These procedures will be unfamiliar to the majority of the UK industry and additional training and site management is likely to be required to ensure their proper implementation on site. Sufficient time for familiarisation, training and site briefings should be incorporated into the build schedule.
Read about steps two, three, four and five in our next article.
Excerpt from “Passivhaus primer: Contractor’s guide. So you’ve been asked to build a Passivhaus?” by BRE.