An architect’s home near Dundee is seeing the benefits of its new roof underlay – even though the reroofing hasn’t finished yet. Neil Simpson, a Partner at Wellwood Leslie Architects, is fitting the Proctor Air® himself while renovating the roof of his stone-walled property built in 1902.
“Proctor Air has been excellent,” explained Neil. “It is relatively easy to install, and has protected us from the weather.The wind used to whistle through the roof before, but we’ve seen a difference straight away in reducing that infiltration.”
Using Proctor Air to protect against the elements – during and after reroofing Situated in an exposed location overlooking the River Tay, the house is subject to the elements. As Neil has continued to live in the property during the work, the underlay had to be capable of protecting the property and its occupants.
Proctor Air has a water resistance classification of W1, and its BBA certificate states the hydrostatic head is greater than 1m.This water hold out performance means Proctor Air can be left exposed for up to three months (although should not be relied upon as being waterproof).
As the frequency and intensity of extreme weather increases, roofs and their underlays need to be capable of withstanding more severe levels of rainfall.A hydrostatic head of at least 1m is the minimum that an underlay should be capable of.
While the reroofing work has not experienced too much rain, there have been strong winds. Proctor Air can be used in wind zones 1-4 without additional measures such as taping joints or additional battens.
What advantages does Proctor Air offer during installation? Other advantages of Proctor Air are its Mullen burst strength and slip resistance performance.
Mullen burst assesses the strength of a fabric, and is a measure of how robust the membrane is during the construction phase. Proctor Air achieves an excellent result. Compared to similar membranes, Proctor Air also achieves a high coefficient of friction, giving slip resistance for increased safety during installation (alongside normal safe roofing practices).
Neil noticed these advantages while working on his roof. He said: “The ability to strip the roof in stages and work in sections, with the slater following on, has been beneficial. Proctor Air has proved very durable, which is what you need when you’re on the roof and working on the membrane.”
Combining traditional Scottish construction with modern building performance
The roof of Neil’s home featured traditional sarking boards, horsehair felt and Scotch slates.The sarking boards were retained, complete with gaps between them, and repaired where necessary.
Being both air and vapour permeable, Proctor Air supports the controlled movement of moisture through the sarking board and underlay layers, to the external environment. Consequently, it inhibits the formation of condensation in the pitched roof, to the point where it’s virtually impossible for condensation to occur under normal conditions.
As Neil observes, there are hundreds of properties in Scotland with roofs like this.That includes most of the village where the house is located.“We need to make use of modern products and technology,” he says. Proctor Air provides consistent ventilation across the whole roof, so Neil didn’t have to install plastic ventilation products that would have detracted from the traditional appearance of the property.
Working with a manufacturer who understands Scottish slating practice gave Neil added confidence.“I’m delighted to see a local company being innovative and creating useful products.The A.Proctor Group has always been that way.”
To find out more about Proctor Air, download the brochure from proctorgroup.com/products/proctor-air