The encapsulation of an asbestos roof at a major pharmaceutical company in Brentwood, Essex, is standing the test of time thanks to Scotchkote liquid roof coating from 3M, the diversified technology company.

Romford-based HBS Ltd, the construction and refurbishment specialist and a nominated applicator of 3M products, was called in to seal and protect a roof containing asbestos at Cardinal Health, part of Martindale Pharma. Rather than using traditional methods such as tar, bitumen or felt, HBS specified Scotchkote, a zero heat, liquid roof membrane, which is easy to apply, and, because it is water-based and totally free of volatile organic compounds (VOCs), is free from odour and any toxic risk. This makes it an ideal material for use on sensitive areas such as occupied pharmaceutical buildings.

Legislation for the removal of asbestos sheeting is closely monitored and complex. Removal should only be carried out by authorised asbestos removal specialists and disposal of this material is strictly controlled. As with almost all occupied premises, it is almost impossible to consider a complete replacement of the roof. Scotchkote allows the asbestos to be safely contained and the entire roof, including potentially dangerous fibres, can be encapsulated with one coat. The application of Scotchkote also creates minimal disruption in the building so the work can be carried out with no loss in site production or revenue.

The roof, an area around 4,300m2, had to be prepared before Scotchkote could be applied. A team from HBS installed safety netting and secure scaffolding before preparing the roof for encapsulation. This involved pressure-washing the existing surface to remove any debris and treating problem areas with fungicide to prevent the re-growth of moss or lichen. 3M Poly-Tech bridging tape was then applied to all the joints, laps, edges and seams across the roof before Poly-Tech reinforcing mesh was added to these points.


HBS prepared and applied the Scotchkote coating to the entire pitched roof area, including all gutters and upstands. This was done with rollers and paintbrushes and was maintained to the exact recommended rate per square metre.

James Brett from HBS Ltd said: "We found Scotchkote very easy to use and apply. With traditional tar-based products, we would have to use a hot works on the roof. Because Scotchkote is applied cold, all we needed were brushes and rollers.

"The results have been great and with such substantial guarantees on the product, we will continue to use Scotchkote. We encapsulate many roofs in varying states of repair. Scotchkote is a rapid and cost-effective alternative to the removal of damaged, leaking or asbestos roofs. I am confident that we will continue to use Scotchkote on all kinds of flat and pitched roof projects and ensure a fully functional and completely safe roof for many years."

Not only is it a cost-effective method for asbestos cement sheet encapsulation, Scotchkote is also an ideal short-term solution for flat asphalt roof waterproofing and is suitable for single-coat application to mineral felt roofs with no priming required. It waterproofs joints, seams and leaks on single-ply roof membranes and needs only local reinforcement to waterproof all types of gutters.

James Gravestock, Business Development Manager, Construction Markets at 3M, added: "Our experience has shown that many traditional flat-roofing methods are prone to early failure. They can easily become brittle and are subject to substrate movement and heat absorption, causing fatigue within the material and failure at the joints.

"Scotchkote liquid roof membrane systems provide a lasting barrier to water penetration, do not embrittle and are highly resistant to sunlight. There is a range of Scotchkote products available that can meet differing requirements and can last between five and 25 years, and beyond, before maintenance is required."

Scotchkote is used throughout the world to protect and maintain buildings, structures and equipment. Flat roof areas can be made weatherproof and waterproof without the need to strip off existing roof materials. Scotchkote guards against corrosion, chemicals and extreme weather. Scotchkote liquid roof membrane systems are guaranteed for up to 25 years.

3M, Scotchkote and Poly-Tech are trademarks of 3M Company.