Exchange Square, Birmingham


Regal M&E and Sir Robert McAlpine
Photo credit: Nikal and LaSalle

Fabric-first approach avoids the need for expensive solar panels

Value engineering the fabric and bespoke Psi values saves hundreds of thousands of pounds

The challenge

This 18-storey building in the centre of Birmingham was over-specifying fabric, M&E equipment and renewables to achieve building regulations. Regal M&E asked Darren Evans to analyse the building specifications to find a solution.

The solution

  • Investigate: our investigations found that the heat loss through the building’s total lintel and jamb details was very high.
  • Reduce heat loss: if we could reduce this heat loss, or more accurately represent it through bespoke junction calculations, then we would be able to achieve compliance through the fabric of the building.
  • Fabric-first approach: we were able to engineer a design solution focused solely on the fabric without the need for bolt-on renewables. We achieved this by focusing on Psi values and thermal mass. We were also more attentive to the building design and the performance of different building aspects.
  • Maximise energy efficiency: Fabric solutions included maximising the efficiency of Mechanical Ventilation with Heat Recovery (MVHR), alongside good architectural details to prevent heat leaving the building.


  • No solar PV on the building.
  • The building design met building regulations with a complete focus on the fabric.
“A building like this would normally require extensive solar PV to meet to building regulations,” explains Brandon Wipperfurth, senior sustainability and energy consultant at Darren Evans. “But by value engineering the fabric in combination with some bespoke Psi value calculations, the building passed building regulations without the need for extra renewables, which saved hundreds of thousands of pounds,” he adds. This project also provided Part L compliance for both residential and commercial areas.

“Darren Evans has always been willing to share knowledge and give practical input and not just plug information into a bit of software and send out an invoice.

“This has enabled me to better serve my client and deliver a solution that I know will work now and, in the years to come.”

Ian Lambert, director, Regal
Regal M&E and Sir Robert McAlpine

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