The project consisted of the re-waterproofing of the administration and kitchen roof which had been troublesome for a number of years. The specification was put forward by Delta Waterproofing. The Danish architect Jacobson designed the roof to hold water which has since proved to be a major problem. With this in mind, the management at St Catherine’s requested a cut to falls insulation to be included in the specification. This was fairly difficult to design as a restriction in raising the perimeter kerbs is in place and also due to the design of the roof with some 238 circular roof lights.

Delta originally specified an overlay in the original asphalt but following a careful inspection, a great deal of ‘ruckling’ was found. It was then decided that the best way forward would be to strip the original asphalt down to the concrete deck.

When Rio Group began works it was evident that the lightweight concrete deck was in danger of being damaged when stripping the asphalt. This meant that we had to revert back to an overlay specification with the ruckling being removed manually to achieve a flat surface incorporating the cut to the falls insulation system.

The system used was very successful in eliminating 98% of the standing water from the roof, as promised to our client.

The project was carried out in winter and despite many problems, Rio Group were able to deliver to the client on schedule.