The old butyl rubber membrane on the low-slope roof areas of a secondary school, in the West Auckland suburb of Green Bay, was hanging-in-there, but deteriorating. With the school scheduled for a re-build in the next 15-20 years, the decision was made to reroof some of the buildings with a medium-to-long-term waterproofing solution.

Driven by previous experience working with Viking Roofspec; having specified Viking waterproofing systems on other Ministry of Education buildings, Auckland-based project risk and management consultancy, ‘Projectability’, selected Viking Enviroclad TPO Membrane as the best solution for replacement of the old membrane.

As the old butyl had lasted and continued to perform beyond the building code’s minimum durability (B2) requirement of 15 years — AND — the existing substrate was thoroughly inspected and deemed sufficiently sloped and still structurally sound, showing no signs of decay, Schedule One of the Building Code applied. This meant a replacement single-ply membrane could be installed without the need for a building consent. The extra protection of Viking’s 20-year product warranty was the icing on the cake.

Once the old butyl rubber membrane had been uplifted, extra screws were fixed into the existing 17mm plywood substrate before the 1.5mm Enviroclad TPO membrane was installed. The Approved Applicator then installed custom-made flashings to correctly detail corner sections of one of the walkways as well as new cap flashings. These were colour-matched to the original, giving the project a cohesive and clean look. The original roof also lacked sufficient cavity vents, so additional ones were installed.

Viking Roofspec’s Technical Specialist completed a post-installation assessment of the school roof, evaluating workmanship quality in terms of seam integrity, roof cavity airflow and ventilation, and watertightness of the outlet and overflows fittings. The installation at the high school passed this quality control test with flying colours.

By thoroughly inspecting the existing roof to ensure its compliance with the objectives of E2, B1 and B2 under NZ Building Code, this non-invasive membrane replacement process under Schedule One prevented a huge amount of construction cost, materials waste, landfill dumping, and noise pollution — plus it eliminated the disruption and inconvenience of relocating students to alternative buildings had the roofs needed demolishing, dumping, and re-building. Not all the membrane installation took place over the school holidays, so this was important and helpful to the school once the students returned.

Viking Enviroclad, with its light grey heat reflective surface, wide sheets and heat-weldable splicing technology, is the ultimate watertight solution. It is CodeMark certified and BRANZ Appraised, providing the highest form of product assurance in the industry, but most importantly (seeing construction materials are only as effective as their installation), Viking materials are only supplied and installed via Viking’s network of Approved Application companies whose installers are licensed at Viking’s training facility. This maximises the level of workmanship with Viking's membrane systems.