← Case studies · Retrofit

Albion House

A 1970s concrete-frame office in Manchester, re-clad and re-insulated while fully occupied — with every junction modelled before it was built.

Heating demand-46%measured, year 1
Airtightness2.1 ACH50from 9.8
Slab-edge ψ0.04from 0.62 W/mK
Embodied carbon-71%vs. demolition
Before
Survey, January 2023Before
After
Survey, January 2025After

The approach

Fix the junctions first.

Our dawn thermography showed that two-thirds of the heat loss came not through the walls but through the slab edges and window reveals. We designed thermally broken brackets for the new rainscreen, wrapped the slab edges and re-detailed every window reveal.

Airtightness was tested floor by floor during works, so leaks were fixed before the cladding closed them in.

Thermal bridge detail

Envelope before and after

ElementBeforeAfterChange
External wall U-value1.45 W/m²K0.18 W/m²K-88%
Windows Uw2.80 W/m²K0.85 W/m²K-70%
Slab-edge ψ0.62 W/mK0.04 W/mK-94%
Airtightness9.8 ACH502.1 ACH50-79%

“For the first time in fifty years the top floor is comfortable in January — and nobody had to move out.”

— Facilities manager, Albion House

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