A project to refurbish an original 1960s flat roof on a Derbyshire school has underlined the high level of flexibility and expertise provided by Gradient Flat Roofing. It also highlights the company’s ability to create factory-cut bespoke insulation to suit specific projects.
The roof of the Simmondley Primary School in Glossop was originally constructed using a factory-produced cranked beam system. This had created a series of varied ridges and valleys across the entire 1,022sq metre roof area, which were topped with a built-up felt and gravel surface layer. The roof design had allowed water to pool in various places, creating areas of thermal stress which had caused the felt layer to degrade.
Derbyshire County Council asked Gradient to design a new insulation layer which would eliminate the existing valleys and backfalls and allow the entire roof to drain effectively. After a detailed examination of the roof, Gradient proposed a combination of cork underlay board and PIR insulation to remedy the situation. Bespoke pieces of tapered insulation would be used to level off the backfalls and create an even roof surface, before a further layer of tapered insulation was then added to create positive falls across the roof and allow rainwater to run off to a series of newly created drainage points. The resulting roof would also provide thermal insulation which exceeded Building Regulation requirements.
“The school stands on a sloping site and together with its prefabricated construction this had allowed the building to settle and cause changes in the roof structure,” adds Gradient’s Steve Adams. “This project presented a considerable challenge but one that we knew we were more than equal to.”
“Once work started to strip the roof back to the original decking we began to find unexpected problems where the original thin decking had failed in places,” says Kevin Campion from project contractors Midland Roofing Services (Derby) Ltd. “We had to remedy these areas before laying a new vapour barrier and this had an impact on some parts of the proposed new insulation solution.”
Close liaison between Gradient, Derbyshire County Council. and Midland Roofing was the key to overcoming these problems. “We knew that we could rely on Midland Roofing to flag up any areas of incompatibility between the existing roof and the proposed new insulation,” says the Council’s Building Surveyor, Jim Swannack. “The Gradient team was then able to examine the roof areas in question, design new solutions and create bespoke pieces of insulation to suit those areas. The technical, design and installation support the company provided was excellent.”
The 23-week project was completed with the application of a 3-ply built-up mineral felt surface layer over the Gradient insulation.
