Asbestos – Best Practice Approach To Roof Refurbishment

For any demolition, refurbishment or repair project, the presence of asbestos in the building can have far reaching cost and health & safety implications. And it’s not an uncommon problem. Asbestos was widely used as a roofing material right the way through to the 1970s thanks to its durability and fire resistance benefits at low cost.

The use of asbestos as a building material is a legacy of the built environment that today’s roofing contractors are often tasked with tackling, as those roofs originally specified in the 1950s, 60s and 70s fail and need to be replaced.  Sometimes, there may be no other option than to remove the asbestos roof and incur the project delays and added costs that specialist remediation involves. However, while the Control of Asbestos regulations 2012 ensures that building owners are accountable for preventing any risk of exposure to asbestos fibres from their building, contractors do not need a license to work with asbestos cement products, such as profiled roofing.  As a result, the most cost and time efficient option for repairing and refurbishing asbestos roofs is often encapsulation of the asbestos so that it no longer poses any danger to health.

The photo above shows the difference between a profiled asbestos roof refurbished using Kemper System products and the unit next door (to the rear) which remains in its original state.

Alternative Approaches

Traditional strip out and disposal of asbestos is an onerous process that incurs additional time and cost on a project thanks to the need for a specialist contractor that will remove the asbestos waste in line with the Control of Asbestos at Work Regulations. There are a number of alternatives, but again, the efficacy and cost of these methods should be considered carefully. A patch repair can be carried out using a paint-on coating and this may initially address an immediate water ingress problem but it is unlikely to provide anything other than a temporary fix. Meanwhile, over-cladding the roof can provide an effective long-term remedy but is also costly and requires consideration for increased weight (structural loading) and height (possible planning permission), as well as the safe removal of loose asbestos particles resulting from fixing operations (internal and external).

The third alternative for upgrading a roof containing asbestos without removing the asbestos is to use a tough, flexible cold liquid-applied waterproof membrane like Kemper System’s Kemperol range to completely encapsulate the roof, ensuring a whole roof solution.  This option not only offers significant cost savings as compared to over-cladding or removing the asbestos and replacing the roof; it also enables the roofing contractor to weatherproof vulnerable bolt-heads and sheets laps and protect the sheet from future physical and biological degradation.

Easy Encapsulation

Unlike over-cladding, which involves handling and drilling of sheets risking the release of asbestos fibres, encapsulating the asbestos with a durable, flexible waterproof membrane involves no drilling, making it safer, better for the environment and more convenient and cost-effective for the building owner/occupier.  However, the process does necessitate thorough cleaning of the asbestos substrate by a specialist contractor prior to application of the membrane and safe removal of any loose asbestos fibres that may result from that process. Specialist asbestos sheet cleaning companies have equipment that can effectively remove moss, lichen and other contamination whilst minimising damage to the surface of the sheet. These systems collect and filter the resultant contaminated water allowing for controlled disposal in line with HSE guidelines.

The roofing contractor can then begin installation of the waterproof membrane using first a primer, and then the waterproofing resin with a reinforcement fleece applied to areas most susceptible to water ingress, commonly vulnerable sheet laps, worn hook-bolts holes and penetrations. Often, contractors choose to use Kemper System’s Kemperol 1K-PUR system for this type of application as it can be applied straight from the container with no mixing and its ‘open working time’ makes it ideal for use on fragile asbestos roofs with restricted access. Once the most vulnerable areas of waterproofing are complete, the contractor then applies Kemper’s liquid waterproofing to the entire roof. Besides encapsulating and protecting the asbestos cement and sealing in the harmful fibres, it reduces future algae growth and the uniform colour provides an attractive ‘like new’ finish.

In this way, the roofing contractor can repair any existing leaks and provide long-term protection against any future wear and tear to the roof with a tough, flexible, seamless membrane.


Asbestos is a word that many building owners, occupiers, developers and contractors dread…..but it needn’t be so. The use of Kemperol on an asbestos roof is comparable in cost to an ordinary roof refurbishment while providing a durable long-term and reliable solution.

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The roof of Worthing Bowling Club – The profiled asbestos roof and the adjoining flat roof refurbished with Kemper System products., 01925 44 55 32,


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