Passive Purple used to seal Beattie Passive Enerphit

This article was originally published in issue 32 of Passive House Plus magazine. Want immediate access to all back issues and exclusive extra content? Click here to subscribe for as little as €10, or click here to receive the next issue free of charge

According to Nathan Beattie of Beattie Passive, the flats are being improved from SAP EPC ratings of D and C and retrofitting to the Enerphit standard – using a new system which not only enhances the performance but addresses fire prevention in the wake of Grenfell, to ensure that the cladding is fire retardant.

“We’ve used Passive Purple as an airtightness membrane – sprayed to the outer face of the original walls,” said Beattie. “Our brackets are then fitted, which creates a void for the Ecobead insulation.” The walls are finished with Magply board, a Frametite weather membrane, battens and a Steni pre-finished render board with a textured finish. The retrofit will also include new Munster Joinery triple glazed windows and a Catnic steel roof.

The project, which started in September, is due to finish by the beginning of February. With airtightness tests pending, Beattie is confident that the decision to work with Intelligent Membranes to spray the Passive Purple airtight layer on the outside of the building – therefore avoiding tricky junctions at party walls and intermediate floors – will be vindicated with a test result below the Enerphit target of 1.0 ACH @ 50 Pa. “They’re a great team that have hopefully made the building airtight in a couple of days. I’m looking forward to the airtightness test. I believe it’ll do well.”

Meanwhile, Intelligent Membranes have partnered with the Woodland Trust in a long-term tree planting initiative. “Every time you place an order, we’ll plant a tree,” said Intelligent Membranes CEO Adam White. “Our aim is to plant 5,000 trees next year on our land in Croydon.” The scheme will involve planting indigenous trees, including oaks and a broad range of species. “We’ll even able to tell you which specific tree was planted for you,” said White. “My aim is to make sure before I retire we help plant a million trees, through also encouraging other companies to sign up with the Woodland Trust – and we’ll offer 5% discounts on all our goods to any companies who prove to us that they’ve signed up too.”