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Columshill Street, Rothesay

Columshill Street, Rothesay

Installation of insulation and secondary glazing


The Columshill Street, Rothesay case study describes thermal performance improvements that were made to a residential building owned by Fyne Homes Housing Association. Fyne Homes were interested to explore simple interventions that would result in cheaper to heat, warmer homes for their tenants.


Existing Fabric

The building in this case study is constructed of lime bonded whinstone with sandstone dressings. It is also category C listed.

At 18 Columshill Street, there are four flats within a two-storey tenement block. The walls have previously been repointed with a cement/sand mix. All flats are accessed from an external stair tower at the rear of the property. Traditional timber glazing is retained at ground and first floor level.


Thermal Upgrades

At the Columnshill Street properties, work was undertaken on the rear stairwell. Internally, the walls were finished in a gloss paint, which could prevent the walls from breathing. This was therefore removed, before a 10mm aerogel blanket was installed. This was finished with two coats of lime plaster and a vapour open clay paint. This ensures the walls can breathe sufficiently. Aerogel is a relatively new material, and is expensive but was very appropriate for this curved, traditional structure.

Aluminium framed secondary glazing was also added to the stairwell windows.


Pre- and post-intervention U-value testing was undertaken by Edinburgh Napier University to quantify improvements in the thermal performance of the building elements.


Thermal Performance
Building Element Stairwell Wall
Construction Details 500mm masonry rubble with 'plaster on the hard'
Pre-upgrade U-value (W/m²K) 1.3
Upgrade Details 10mm aerogel blanket, mesh and plaster
Post upgrade U-value (W/m²K) 0.6


The measures adopted in the Columshill Street properties in Rothesay were relatively simple but have demonstrated good levels of thermal improvement. By retaining the existing windows and doors, there was little impact on the original fabric, nor any disruption to the tenants.

The improvement measures outlined in this case study could be replicated in similar homes across Scotland.

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Case Study

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U-value Testing Methodology