In 2008 CRL Roofing were commissioned to Waterproof Cadbury’s Chirk Factory roof, Wrexham.

The existing roof slab was constructed of aerated concrete pre-cast slab on steel ‘I’ section beams that were originally placed over 30 years ago.

The ideal solution would have been to completely remove the existing roof covering and start a fresh to the prepared slab, however due to the factory being in use all year round, this was not possible due to the risk of contamination to the food product below when the existing roof covering was removed. Even cleaning the existing roof covering was an issue as water jet wash was considered to risky by the client should the excess water leak through.

Following consultation with BASF Construction Chemicals and the client the following remedial action was agreed:

• Clean the roof area by hand, vacuum & air techniques
• Loose areas of isolated felt were cut back and immediately replaced with self adhered felt
• Low areas were built up using consecutive layers of felt

As we were unable to remove the existing felt roof material, air vents were incorporated into the new system to allow for moisture/vapour escape from the existing system once the new system had been applied over.

When fully cleaned and dry the prepared substrate was primed in a thin uniform coat and allowed to cure. Once the primer had cured, Basf Conipur Membrane 802FL was spray applied in one operation to form a monolithic membrane 1.5mm thick.

Following application of the 802FL, Basf Conipur Wear coat 880 was applied incorporating oven dried quartz into the still wet wear coat.

Client: Cadbury Trebour Bassett

Value: £697,000.00