Klober offers the ultimate weatherproof underlay

17 Apr 2019

Klober‘s Permo® extreme RS SK2 waterproof and tear-resistant underlay offers the ultimate solution for low pitched roofs.

Suitable for profile tiles pitched at 12.5o or more, 15o for slates and 22.5o for plain tiles; the Permo® extreme RS SK2 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 whilst keeping rainwater 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. Therefore, Permo® extreme can provide a temporary weatherproofing layer if required.

With 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.

In addition, Permo® extreme dispenses with the need for plywood or OSB support boards and counter battens – which the company saves around £8 per m2 in materials at the minimum, plus 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 – proving much more durable than most interlocking tiles.

Permo® extreme also offers a great solution 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.

Klober also offers 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.

Klober Ltd
Unit 6F,
East Midlands Distribution Centre
Short Lane
Castle Donington
Derbyshire
DE74 2HA

Tel: 01332 813050

Visit Klober's website