Last year (2018), SBS completed external wall insulation works to six high-rise residential blocks at Scholes Village in Wigan. The properties were all occupied and included five 12-storey blocks, and a more complex 10-storey block.
In May 2019, we commissioned an aerial survey of the finished results. As the accompanying photographs show, the finish still looks pristine and the system as a whole is performing flawlessly.
Growing Demand for High Rise External Wall Insulation
One of the reasons for the survey was to secure photographic evidence of our work on high rise buildings. Fire safety on high rise buildings has become a key concern for social housing providers and, as one of the very few UK contractors to be accredited to install SWIGA-backed systems on high rise buildings, SBS has found itself tendering for a steadily increasing number of projects.
Some of these new opportunities include projects similar to the £2.2m Scholes Village scheme. This was commissioned because another contractor had previously installed a cladding system that had subsequently failed. By 2012, the properties were suffering from water ingress and damp, and some sections of render were falling away. Using insurance funding, Wigan and Leigh Homes decided to strip the old system and install a new, BRE-accredited, SWIGA-approved system in its place. The chosen solution was a PermaRock Mineral Fibre external wall insulation system.
For SBS, part of the selection process involved taking the client and insurers to multiple high-rise sites to view schemes delivered by SBS and featuring PermaRock insulation systems. Since 2012, SBS had installed external wall insulation systems to over 35 tower blocks, including 10 installations that involved the stripping-off of failed cladding systems and the re-instatement of a new external wall insulation system. Collectively, the senior management team had experience of installing external wall insulation systems to hundreds of high-rise buildings.
A Fire-Safe EWI System
PermaRock's Mineral Fibre external wall insulation system is extremely well suited for application to high-rise buildings, where the highest levels of fire resistance and non-combustibility are required. It is independently assessed (BRE Certificate 158/12) with a minimum 30 year assessed lifetime, and supported by a SWIGA 25 year guarantee.
- Excellent fire performance: non-combustible mineral (stonewool) fibre insulation (Class A1) - Fire breaks not required
- A2-s1,d0 reaction to fire classification (EN 13501-1:2007+A1:2009)
- Suitable for use on buildings with storeys over 18 metres high
- Adhesively bonded and mechanically fixed insulation: resistant to wind loads
- Mechanically anchored reinforcement layer: Provides enhanced resistance to wind loading and additional structural stability in fire.
The specific system chosen for the five 12-storey blocks was a 100mm dual-density, non-combustible mineral fibre insulation system. This featured a brick slip finish on the ground level, and a SiliconeUltra K 1.5mm Finish on the eleven floors above.
The PermaRock Mineral Fibre EWI System - either with the Silicone Ultra K-Finish (1.5 mm) or with Brick Slips - has been rated Class A2-s1,d0 and therefore meets the latest (post 2018) requirements for fire performance for buildings with a storey height over 18m.
The renders allowed a significant choice of colours but for this scheme, lighter colours were recommended in order to minimise thermal gain. All the chosen finishes were based on a hybrid silicate nano-quartz product. This offers superior performance to silicone renders in terms of water vapour permeability, resistance to mould and algae, and its ability to inhibit the accumulation of dirt. The effectiveness of these characteristics was confirmed by the recent aerial survey.
SBS completed its work on the first tower block in September 2016, and on the strength of its success, it was awarded the contract to complete the remaining towers. Thereafter, SBS worked on either one or two blocks at a time, with approximately 50 operatives working on site at peak times.
SBS began blocks two and three in October 2016. Work on the next two towers was undertaken over the course of 2017, and the final block was completed in the summer of 2018. Effective resident liaison helped to ensure speedy completion with minimal 'no access' issues.
SBS completed all works on budget and in line with the agreed schedule. Strict quality control procedures ensured that the exterior wall insulation system was installed precisely to specification.
Resident surveys revealed high levels of satisfaction with the work, and the scheme was completed with a record of zero defects and 100% handover success.
All works on the six tower blocks were supported by a 25 year SWIGA guarantee.
We will be publishing details of our work on other high-rise buildings shortly.