Flat roofs adapt for net zero

Tom Raftery, Sustainability and PV manager at Bauder, shares his thoughts on how flat roof design is changing to meet the needs of a net zero future.

The UK government’s ambitious targets for net zero, with interim targets for 2030, 2035 and onwards to 2050, are strong drivers for designing future-proof buildings, with a full decarbonised life cycle embracing design, construction, building management and ongoing refurbishment or deconstruction.

A flat roof is an integral part of many modern construction designs as it provides additional utility space for the building, whether for recreational, environmental, or functional facilities. 

So how will you maximise a flat roof design to help deliver net zero?

Level one – Insulate, insulate, insulate
A fabric first approach should always be undertaken. Reducing heat loss is one of the key pillars of any decarbonisation design. This does not only mean thicker insulation but also robust detailing to prevent cold bridging.

Level two – Design for circularity
Roof systems should be designed to ensure that they are durable, easy to maintain and repair, and eventually deconstruct. The method of installation (i.e. adhered or mechanically fixed) is often as important as the products themselves when it comes to how the products will be dealt with at the end of their serviceable life. It is also important to remember that the primary function of a flat roof is to keep the building watertight and secure. Any materials and systems chosen for their circular or net zero properties must not detract from this, and all systems should meet the various construction standards such as BROOF(t4) reaction to fire.

Level three – Include energy generation
The installation of site sourced renewable energy is central to reducing the operational carbon debt of any building. A rooftop solar PV array will not only provide renewable energy but also significantly reduce the building’s running costs. To take it one step further, include a green roof to make a biosolar system which provides both energy generation, biodiversity, and water management.

Level four – Design for resilience
We are already in a warming world, with extreme weather events becoming ever more prevalent. Designing roofs to ensure they can both withstand these events and reduce the impact of them on our buildings will become more important. This could be simply ensuring that upstands are all the correct height to withstand more intensive rainfall periods. It could also take the form of a green roof that helps to protect and extend the life of roof membranes, reduce flash flooding, and keep our urban areas cooler.

Flat roofs provide numerous options to help construction professionals design buildings to meet net zero. At Bauder, sustainability is one of our core values, and in 2023 we will be launching our net zero action plan. We are looking forward to working with other businesses whose values align with ours.

More on design and specification