Project Overview:
Background:
When Nottingham City Homes sought to upgrade two high-rise tower blocks and to provide a new retirement village for the city, it also decided to build a new 44-bed extra care facility on the land between them. It appointed the architects, Halsall Lloyd Partnership (‘HLP’), to develop the necessary plans. (The refurbishment of the two tower blocks is detailed in a separate case study. See Winchester and Woodthorpe Courts.)
The new building, to be known as Winwood Court, would feature a braced steel frame on the ground floor, and a lightweight Fusion SIP framing system on the upper storeys. It would also require an external wall insulation (EWI) system, together with rain screen cladding and decorative renders in a range of colours and styles.
The Brief:
It was important that the external appearance of the building would match that of the adjacent tower blocks, which were to feature a ‘patchwork’ of rectangular panels. Consequently, the design called for coloured render in a matching range of muted colours. The ground floor would be finished with a traditional brick façade, while the upper three levels would feature a range of greens and greys.
The Design Stage:
The project architect HLP selected PermaRock Mineral Fibre EWI system as a result of close engagement with PermaRock’s Technical Services staff who helped to produce the necessary specifications, visualisations and detailing. The same system was specified for the accompanying tower blocks.
PermaRock also supported the team with U-value calculations and worked with the architect to help design the system interfaces with other building elements such as windows, doors, roofs and enclosed balconies. When roosting swifts were discovered in the building, the team also developed designs to incorporate nesting boxes into the EWI system.
Specification and System:
For the majority of the walls, SiliconeUltra K finish renders were applied over the reinforcement layer in various colours. Some elevations featured solid, unbroken colours while others were applied in different shades and with ‘feature joints' to create the panellised appearance originally envisaged in the cladding design.
SiliconeUltra K finish renders are lightweight, water-repellent and demonstrate excellent water vapour permeability. They are through-coloured and resist the accumulation of dirt, so they tend to retain a clean, bright appearance even in challenging urban environments. Similarly, an anti-microbial preservative helps to resist the growth of unsightly moss and algae. SiliconeUltra K-finish renders are available in an extensive range of colours and a choice of textures and grain sizes: 1.5mm, 2.0mm and 3.0mm.
Performance: Thermal Insulation
PermaRock’s Mineral Fibre insulation has a thermal conductivity of 0.036 W/mK and when applied at 70 mm thickness over the Fusion SIP panel supporting structure, the calculated U-value for the wall was 0.17 W/m2K – demonstrating a high level of thermal performance and significantly better than Building Regulations requirements at the time.
Performance: Environmental Sustainability
A full environmental assessment of the PermaRock Mineral Fibre EWI System, using the BRE methodologies for Environmental Profiles (1999) and Ecopoints (2001) established that the system achieves an Ecopoints score of 0.10 (m2) with a life cycle of well over 60 years – the recommended lifespan of buildings in the UK.
This assessment considers the whole life effects of the EWI system in relation to climate change, pollution to air, pollution to water, acid deposition and ozone depletion, as well as mineral extractions, water extraction and waste disposal. This Ecopoints score equates to a Green Guide rating of A or A+ ‘Excellent’.
Performance: Fire Safety
The PermaRock Mineral Fibre External Wall Insulation system has an A2-s1,d0 Reaction to Fire classification (EN 13501-1) and is suitable for use on buildings of any building height, including those of above 11 metres.
Result:
Throughout the scheme, PermaRock Technical Services provided ongoing support to the design team and to the specialist subcontractor appointed to install the PermaRock system.
The scheme produced an extremely impressive transformation, creating 44 high-quality apartments. The project was widely appreciated by residents and it went on to secure a host of awards:
- Inside Housing Development Awards 2021: ‘Best Older People’s Housing Development (rural and suburban)’ category
- RICS Social Impact Award 2020 East Midlands (residential category)
- Building Communities Awards 2020: Project of the Year (over £3m category)
- East Midlands Awards 2019: East Midlands Scheme of the Year
- fbe East Midlands Chairman’s Annual Dinner: Chairman’s Award for Project of the Year