The challenge
Orchards Academy in Swanley, London, is one of several schools that has recently invested in refurbishing their roofs with a Triflex cold liquid applied waterproofing system. Educating boys and girls from year 7 through to post 16, Orchards Academy prides itself on the high level of education and facilities that they provide.
The school is a three-storey structure that was built in the 1960’s. It is a U-shaped building that features low-level roof lights and ballasted photovoltaic panels. The building had been suffering from water ingress from the roof but during the initial inspection, the roof appeared to be in a reasonable condition. However, any surface defects that may have been present were masked by the existing finish, which contained limestone chippings. The chippings had developed a considerable amount of moss and vegetation over time, and held vast amounts of water.
In addition to the scope of work the Multi Academy Trust operating Orchards Academy who operate the property through their project manager Ridge & Partners LLP outlined that they required a solution that did not require the use of hot works, as they felt this posed too much of a risk to the building, students and staff. Lastly, the thermal performance of the roofs also needed to be upgraded as the minimum requirements of Part L2B of the Building Regulations were not being met.
After carrying out a free on-site survey, core samples were taken to identify the underlying build-up, allowing the Triflex Technical Team to provide the most accurate specification.
The solution
Based on the on-site survey and testing results, it was determined that the best solution would be to install a Triflex ProTect warm roof system. This system was specified following calculations done to determine the thickness of the insulation material, ensuring the necessary U-value would be achieved. The Triflex ProTect warm roof system allowed the building to meet the requirements of Part L2B of the building regulations and provides a solution that poses no risks from hot works, as it’s totally cold applied.
Prior to installation it was specified that our Authorised Contractor, Makers Construction Ltd. should remove the limestone chippings and vegetation before installing the waterproofing system, in order for a strong bond to be made between the surfaces. Following this removal, it was apparent that the chipping finish had proven to be detrimental to the roof by denying water to flow towards the drainage channels. This had led to cracking and water ingress to the asphalt below.
Fortunately, Triflex solutions are hydrolysis-resistant, so if there were to be issues with standing or ponding water in future it would have no adverse effect on the waterproofing. Triflex ProDetail was used to waterproof various details, including upstands, the ballasted photovoltaic panels and the new roof lights which were installed at the same time.
The combination of excellent time management from Makers Construction Ltd. and the exceptionally fast cure times of the PMMA (PolyMethyl MethAcrylate) resin-based system Triflex ProTect, meant that works were carried out efficiently and effectively, during school time while meeting all deadlines.
Triflex proposed a waterproofing system and also upgraded the insulation to comply with current building regulations. The solution helped with our funding application and the cold applied products meant there was no fire risk and limited noise so allowed Triflex to adapt to our programme requirements and term time installation with little disruption to our school.
Triflex and their approved contractor attended a pre start meeting. Regular planned visits by Triflex site technicians were carried out with written inspection and progress reports following. All the Triflex team were DBS checked. The roof was completed on time with a robust system warranty for the required period.
Alison Pearce - Business Manager, Orchards Academy
