St Luke’s CofE Primary School with Thermaweld

An IMA Approved contractor delivers a complex solution for a failing school roof, using BMI Icopal’s Thermaweld system.
Thermaweld
St Luke’s CofE Primary School hero

St Luke’s CofE Primary School, Bury, was an 800m² project made up of various flat roof areas, the majority of which had suffered due to age - some to the extent that there was severe slumping, blistering and large cracks within the existing asphalt.

The overall project was to completely refurbish all of the school’s roof areas and improve their falls in order to relieve any ponding water. 

D Shawcross Roofing was appointed as the roofing contractor to take on the work, which commenced in November 2018. It was also noted that there was not enough natural light coming into the school hall, so it was decided to allow for more rooflights to be included.

Testimonial

Testimonial

 “A laser level survey was conducted by BMI to find the best way to remove the extreme ponding water described and two tapered schemes had to be designed to create the desired fall, all while having to consider the removal of the redundant tank room which was adjacent to the ponding.”

Tony Brown, D Shawcross Roofing

St Luke’s CofE Primary School testimonial image

The Challenge

The Challenge

The highest level, which had an extension built onto one of its sides, caused the original roof’s point of relief to be blocked off, combined with the opposite side drainage and poor fall in that direction, meant that the ponding water in this location could get to around 60mm deep, across a large area, before reaching the opposite drip edge. 

However, the condition of the asphalt roofs meant they could be overlaid as long as the slumping and blistering were investigated further and remedied. The single-ply roofs had obviously already failed, which was concerning as they were not that old, and they had already received a full liquid overlay, but this had been inadequately bonded to the single-ply membrane and appeared as a completely separate membrane, which therefore meant the entire system needed stripping down to the deck.

St Luke’s CofE Primary School The Challenge image

The Project Preparation

The Project Preparation

There was quite a lot of structural work which needed to be done in addition to the roofing works already specified for this project. For example, four new large rooflights needed to be installed within a roof which was made up of a wood wool slab deck with asphalt above, making this part of the project particularly challenging. 

Additionally, the tank room needed to be completely removed and disposed of, all while ensuring the levels were met for the tapered scheme which would follow above. Beneath the overhangs of adjacent extensions, new timber upstands were needed to receive the waterproofing, as the height of the new roof would otherwise have made any detailing almost impossible.

Getting the original asphalt waterproofing into a decent enough condition for the new system to be installed also proved to be an extensive job, as the number of cracks and blisters meant that once again preparation was just as key as the installation itself.

The raising of windows and their cills in numerous locations also added to the amount of preparatory work needed.

St Luke’s CofE Primary School The Preparation image

The Solution

The Solution

It was found that existing asphalt could be overlaid, but the single-ply areas had failed and needed to be stripped completely. To achieve this, varying decks of woodwool, metal and plywood, with asphalt waterproofing, as well as a new single-ply system were used across 6 separate roof areas.

Tapered insulation and tapered gutters were installed in specific areas, as the intention was to remove drainage to the exterior of the building as much as possible. The build up consisted of either SA Primer and Torchsafe TA VCL – Stripes to Flammable Substrates or Siplast Primer and Total Torch VCL to Non-Flammable Substrates, either Tapered, 120mm or 130mm Thermazone Roofboard Insulation (Dependent on U Value requirement and height required to allow for the tapered gutters). For much of the project, BMI Icopal Torchsafe TA Underlay was deployed, finished with a Firesmart Thermaweld Charcoal Capsheet. 

St Luke’s CofE Primary School The Solution image

Thermaweld

Thermaweld

Tested. Trusted. Tailored.

Thermaweld is one of the UK’s most trusted bitumen flat roofing systems, it’s tried, tested and reliable so you and your clients don’t have to worry.

Key features

  • Faster application because of its unique mini groove technology

  • Technically advanced low heat-reactive bitumen

  • Lap security for maximum resistance to wind uplift

  • Tested, Tailored. Trusted, with up to 20 year guarantee

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