Permo
extreme RS SK2 from Klober – Europe’s leading manufacturer of high-performance
roofing membranes, ventilation and accessories – is a waterproof,
tear-resistant underlay, designed for use on low pitched roofs.
Suitable for profile tiles pitched at 12.5o or more, 15o for slates and 22.5o for plain
tiles; it is manufactured from a bondable two-layered underlay with a
shrink-resistant TPU coating on a robust PES (polyethersulphone) fleece which
allows vapour to escape, while keeping rain water out.
Double
self-adhesive edge strips provide a permanent seal and immediate
weatherproofing against wind, rain and snow; while the PES fleece also
incorporates a capillary stop to control the formation of condensation. This
means that, unlike traditional vapour permeable underlays which provide limited
weather protection if left, Permo extreme can provide a temporary
weatherproofing layer if required.
With a
high-temperature stability that peaks at 100°C and due to the fact that it is
very UV-resistant, it also means that Permo extreme is highly suitable for
installation under in-roof system solar panels.
Another benefit of Permo extreme is that it dispenses with the need for
plywood or OSB support boards and counter battens – which the company estimates
saves at least £8 per m2 in materials at least, not to mention time and labour
costs.
This ability to self-support was established through in-depth testing
at the Building Research Establishment (BRE). In the BRE tests, Permo extreme
RS SK2 was laid at 12.5o with no slates or tiles on top of it and a 10-to-15mm
deep drape between rafters, in line with the current version of BS 5534.
The
underlay was fastened with tacks and 50mm Butylon tape fixed down the rafters
to seal any penetrations. Battens were installed with fixing nails through the
tape and the next layer of Permo extreme laid with a 100mm headlap so adhesive
strips met.
The first
test was a rain deluge designed to create a one-in-fifty-year condition. The
second combined wind, rain and suction from underneath, with all three elements
increasing every five minutes over a 55-minute period, again mimicking a
one-in-fifty-year condition.
For
context, most interlocking tiles start to leak at between 25 and 30 Pascals,
while Permo extreme was tested at over 110 Pascals – without any water ingress
at all.
It’s also
the ideal choice for those seeking a bondable underlay for a rainproof
sub-roof.
Not only
is it tear-resistant, highly weatherproof and avoids the need for sarking
boards, it also – when laid as a key primary barrier with its associated
accessories – comes with a 10-year guarantee providing that it has been
installed in accordance with Klober’s installation instructions.
Permo
extreme RS SK2 is complemented by a range of accessories such as Permo extreme
sealant which allows connection to rising structural components and eave
flashings; an EPDM sealing collar suitable for the sealing of pipe
penetrations; and Butylon tape, which is ideal for creating seals around nail
penetrations.
Beyond the
best performing products and customer service in the sector, Klober also offers
unrivalled training and technical support to its customers.
