St Michaels Mount receives new Permanite roof

A Permanite Asphalt product story

Edited by the Buildingtalk editorial team Jun 4, 2009

Permanite Asphalt Permaphalt mastic asphalt roof system has helped restore the National Trust valued St Michaels Mount in Cornwall.

Steeped in over 1000 years of history, St Michael's Mount required a refurbishment programme on the pedestrian walkway of the South Viewing Terrace, which commenced in January 2009.

The existing walkway was old and beyond repair and it was essential that the replacement should be very hardwearing and completely watertight to protect the domestic quarters underneath.

To meet this requirement, Permanite Asphalt were contacted by Fernie (Asphalters), a national roofing contractor based in Truro, to refine the asphalt specification.

Waterproofing a project like this presented considerable challenges, particularly the transportation of nearly 30 tonnes of mastic asphalt and other essential materials to the top of the Mount.

Once on the island the materials were placed in a small cart and hauled up from sea level through a tunnel carved through granite rock to the castle at the top of the Mount, before being unloaded and barrowed to the far South facing side of the castle.

A helicopter from RNAS Culdrose was also enlisted as a training exercise to lift the mastic asphalt plant and machinery into position near the top of the Mount.

In total there were 350m2 of walkway/roofing that needed renovation.

The material used for waterproofing the project was Permaphalt polymer modified mastic asphalt, which was installed in two 15mm layers to give an overall thickness of 30mm.

Commenting on the project, Phil Fernie, Chief Executive of Fernie (Asphalters) said, "St Michael's Mount is now protected by a superior mastic asphalt system that has an insurance backed 20 year guarantee, and there is no doubt that the replacement roof will remain serviceable for a much longer period".

Permaphalt is LPCB approved, and is a specially formulated mastic asphalt roofing, using advanced polymer technology to give the long term durability, increased fatigue resistance, improved temperature stability and ease of installation.

It can be applied to form a continuous waterproof covering over flat, sloped or curved surfaces.

It can be worked around pipes, roof lights and other projections to a completely seam free waterproof membrane.

For more information on Permanite Asphalt, visit the website.