Roof renewal overlays can significantly and economically extend a building's lifespan while addressing key environmental concerns in the construction industry. As buildings age, roof renewal becomes an increasingly important consideration for property owners and architects seeking to improve performance, sustainability, and longevity.

Key benefits of renewing an existing roof are:

1. Improved weathertightness: The primary reason for roof renewal is often to address weathertightness issues, which are a significant concern for both tenants and building owners.
2. Minimal building disruption: Roof renewal can be accomplished without disturbing tenants, allowing for continued productivity within the building.
3. Environmental impact: Renewing a roof reduces the need to remove and dispose of existing materials, minimising waste and the introduction of new materials.
4. Enhanced thermal insulation: Roof renewal presents an opportunity to improve thermal insulation without disrupting the building's interior.
5. Acoustic performance: The renewal process can also enhance the building's acoustic properties.

For flat roofs with structurally sound substrates, a new single or double membrane can be applied directly on top of the existing membrane. If the existing membrane is worn, a recovery board can be installed before applying a new membrane.

The Nuraply 3PM membrane can be overlayed two times to extend the expected life span of the roof up to 100 years.

To improve a building's insulation, or for refurbishing a metal tray roof, many of which have low falls, PIR (Polyisocyanurate) insulation board can overlay the existing roof before installing a membrane roof.

Environmental considerations

Embodied carbon refers to the energy consumption and environmental impact associated with the manufacturing, transportation, and installation of products and materials. One of the key benefits of re-roofing a building is the ability to preserve much of the existing structure, reducing the need for new materials and extending the building's lifespan. This process not only prevents a significant amount of waste from ending up in landfills but also lowers the embodied carbon footprint by minimising the use of new resources. Currently, construction waste is not directly addressed by the building code, yet reducing it plays a crucial role in curbing embodied carbon over the extended life of an existing structure.

Case Study: Life Church Roof Renewal

Life Church was in search of new premises with a prime location and a spacious building. They chose to convert the former Bic Pen factory on Normandy Road in Mount Eden. The factory, with its outdated tin roof, was no longer fit for purpose and required significant upgrades to make it habitable. The project involved overlaying an existing standing seam metal roof with an insulated membrane system.

Existing roof: The original roof was a standing seam metal structure

Preparation: After structural inspection, packers were used to fill the trays of the existing metal roof

Vapour control: A continuous vapour control layer was installed beneath the insulation

Insulation: 80mm of PIR insulation was laid across the entire roof surface, providing an additional R-value of 4.5

Membrane: The New Reply 3PM membrane system was installed over the insulation

This system is known as a Nuratherm Warm Roof. It provides significant acoustic properties. The Enertherm layer provides continuous insulation around the building envelope. The additional weight of the new system was approximately 4-5k kg/m². 

Conclusion

By offering solutions that improve building performance, reduce environmental impact, and extend the life of existing structures, Nuralite is addressing key concerns in the construction industry. Nuralite’s commitment to environmental building practices and innovative renewal techniques positions them at the forefront of sustainable roofing solutions.