Project Overview:
Background:
In 2018, PermaRock was part of an ambitious plan by developer Blackacres Limited to convert Coniston House, a former office building on Chapel Ash Island in Wolverhampton, into a luxury residential development with 42 modern apartments. The remodelled building would become known as Belvedere Residence.
The building had originally been occupied by 500 workers at the Marstons brewing company but when the business relocated, no new commercial tenants could be found and the property then remained vacant for nearly two years. It was described as a ‘tired Wolverhampton landmark’ in the Wolverhampton Express & Star. However, the Midlands-based property developer Blackacres saw the potential in it and commissioned the necessary conversion work.
The Brief:
An important aspect of the project entailed improving the building’s insulation and part of that included fitting external wall insulation. The original intention was that the external walls would be externally insulated with a rainscreen cladding panel system in several colours. However, owing to technical difficulties and the high cost of this original design, the developer contacted PermaRock to discuss the possibility of using an alternative. This would be based on a PermaRock EWI system with a render finish supplied in green, white and grey. This would create the same multi-tonal ‘panelised’ appearance that had been envisioned with the original cladding panel design, so it was important that the chosen system could reproduce the desired aesthetic effect.
Design and Specification:
The external wall insulation system chosen for the project comprised a PermaRock Mineral Fibre external wall insulation (EWI) system with 100 mm insulation adhesively bonded and mechanically fixed to the various substrate types.
A wind load assessment was carried out to establish the dynamic pressure acting on each elevation of the 13 m high, flat-roofed rectangular-form building. From this, the mechanical fixing arrangements for the PermaRock system were calculated for each exposure zone of the building. PermaRock’s Technical team used data from laboratory pull-through/pull-over tests, and carried out in-situ pull-out tests with the proposed fixings to confirm the fixing design. This ensured that the structural stability of the system could be achieved against the design wind loads.
Thermal calculations and condensation risk assessments were also carried out by PermaRock to confirm the U-value requirements.
The external wall insulation system was duly installed, with 100 mm of non-combustible mineral fibre insulation adhesively bonded and mechanically fixed. A reinforced basecoat of PermaRock Bedding Mortar & PermaRock Reinforcing Mesh was applied over the insulation. Non-combustible reinforcement layer fixings were installed through the basecoat to provide additional wind resistance and fire safety.
For the decorative finish, PermaRock SiliconeULTRA K-Finish was chosen in white and three colours: Mai 70, Amber 30 and Jura 15. These were applied to create a ‘panelised’ appearance, with a 20 mm wide anthracite-coloured ‘shadow gap’ joint detail between each of the coloured panels.
Design Challenge:
An important consideration for the system designer was the presence of live horizontal structural movement joints on each storey. The design of the external wall insulation system therefore had to accommodate these joints, bringing them through at each floor level. This was achieved by the incorporation of horizontal ‘compression’ movement joints in a light grey colour at the first and second floor levels, coincident with the movement joints in the substrate.
Performance:
The external wall insulation system worked in combination with the new twin-skin light steel-framed walls, which were partially infilled with mineral wool insulation. Together, they achieved a calculated U-value of 0.22 W/m2K.
Result:
The project was completed in 2019 although, as local estate agents reported at the time, apartments began selling before work had even begun. A spokesperson for the local estate agent, Connells in Wolverhampton, said:
“I've been selling lots of apartments in Wolverhampton for more than 20 years now and I've never seen such a fast response as this. We had already sold 30 per cent before work had even started.”
Then Deputy Mayor of Wolverhampton, Phil Page, praised the building’s design, saying:
“I think it looks really impressive. It’s modern, it’s colourful and it fits in with Wolverhampton’s new, modern image.”