The Highlands' first Passivhaus school features offsite Wraptite® installation

Responsibility for installing the membranes fell to Veitchi Interiors, as part of the company’s scope of work to erect the Metsec framing system, complete with insulation and air and vapour tight membranes.

For Project Manager George Bitters, working on Tain Campus was his first experience of both a Passivhaus project and using Proctor Group membranes.

“I had an understanding of the fundamentals of the Passivhaus standard, and also did the Passivhaus Tradesperson course,” he explains. “I wouldn’t say we have found it difficult to meet the standard. In fact, it has been enjoyable.”

Veitchi Interiors played a proactive role in determining how the project was delivered. Thanks to having their own Metframe panel factory, they proposed installing the Wraptite membrane in the factory. This was discussed at the project’s pre-start meeting, and both Highland Council (client) and Kier (main contractor) were happy to explore it.

“Applying Wraptite in the factory allowed us to achieve a perfect finish,” says George. “We got no bubbles spoiling the appearance or causing concern that the performance of the wall build-up might be affected. The only real downside is needing to then transport the finished sheathing to site.”

In such a northerly location, and also on the coast, weather has inevitably been a factor. Removing the labour of the Wraptite installation meant the only work then needed on site was the application of tapes where required to fully seal the system against the wind and rain.

Another approach adopted by Veitchi was to complete the external and internal membranes on a single room first.

“We air tested it to make sure of the right result,” says George. “It lets everybody see what they’re getting and sets the standard to follow for the rest of the project.”

This is similar to the test rig constructed at Faifley Campus, which also helped to iron out any issues at an early stage.

Alongside more formal Passivhaus training, Veitchi Interiors received an array of technical support from Proctor Group to support the use of its two membranes. Regional Sales Manager Linda Kay delivered a CPD training session on the products and followed that up with multiple visits to site.

“Linda has been very good,” says George, “and the technical department has also been very helpful when we’ve had queries about the products. Overall, our experience with the products is that they’re very good membranes.”

Wraptite is both airtight and highly vapour permeable, helping to achieve high standards of airtightness without increasing condensation risk in the structure. Its self-adhered installation is designed to ensure a consistent airtight external seal. The membrane’s credentials as a high-quality product suitable for use in Passivhaus buildings are reinforced by its accreditation as a Passivhaus-certified component.

Procheck A2 is a vapour and airtight membrane that is also rated A2-s1,d0 when classified to BS EN 13501-1. It is therefore considered non-combustible, with no contribution to fire. Its composition gives the membrane a high degree of vapour controlling properties, as well as being airtight, which allows its use as an AVCL and helps contribute to the thermal efficiency of the building.

Final air pressure testing at Tain Campus was carried out in July 2025. The test result is crucial to being able to meet the requirements of Passivhaus certification, with a target of 0.6 air changes per hour (ACH) having to be met.

Finlay Niven, Project Manager at Kier, said: “The building achieved 0.15 ACH, which is a fantastic result.”

Find out more about Wraptite:
https://proctorgroup.com/products/wraptite

Find out more about Procheck A2:
https://proctorgroup.com/products/procheck-a2