This case study explores how Rugby Borough Council were able to deliver the demolition and re-development of five 11-story tower blocks that were all constructed using Large Panel Systems (LPS).
Introduction
This case study explores how Rugby Borough Council were able to deliver the demolition and re-development of five eleven-story tower blocks that were all constructed using Large Panel Systems (LPS). Following an intrusive and thorough survey of their buildings, this case study highlights the proactive approach taken by Rugby Borough Council which has improved the quality of social housing for their residents.
The challenge
Rugby Borough Council (RBC) owned five eleven-storey tower blocks built in the 1960s; they were spread over two locations across the borough; Biart Place and Rounds Gardens. The buildings in both areas have received considerable investment over the years, including thermal and structural upgrades.
The five tower blocks across the two sites offered considerable housing allocation representing roughly 8 per cent of RBC housing stock, including 132 social homes in Biart Place and 211 social homes in Rounds Gardens.
The tragic collapse of the Ronan Point 22-storey tower block in East London in 1968 encouraged authorities and building owners to evaluate their Large Panel System (LPS) constructed buildings, with many authorities choosing to undertake strengthening works to mitigate the risks of similar incidents.
The five Rugby tower blocks were all LPS constructions, similar to Ronan Point. The buildings received structural upgrades, including strengthening measures above the seventh floor. In addition, the Rounds Gardens premises were re-clad in brickwork as part of a refurbishment in the 1980s to improve thermal efficiency and to keep the premises modern and attractive to tenants.
The five tower blocks were well-occupied but were challenging to manage. With several tenancy issues related to the age of the buildings, the units needed to be more attractive to tenants (heating costs), and annual recurrent costs were rising due to increased maintenance.
The risk that needed to be addressed
As part of RBC's routine safety management, a regular inspection was conducted on all high-rise premises. This included a five-yearly visual inspection regime which noticed issues in 2015, including areas of concrete that had started to loosen from the panels. The council correctly and quickly recognised that further information about the construction's safety was required to assure the tenants that the premises were safe to occupy.
A construction inspection was carried out in 2016, which identified several potential safety issues that needed further investigation; this triggered planning for a fully intrusive survey of the block's construction, which was completed in 2017.
The intrusive survey uncovered several safety issues which threatened the long-term viability of the premises, including:
- poor dry-pack insulation
- lack of connecting ties between slabs
- missing bolts, dowels, and loops
- the onset of corrosion to steelwork
- carbonation and chloride levels within the concrete
- inconsistent floor panel construction and concrete depth.
The intrusive survey works RBC carried out were thorough and included inspecting vacated unit's floor and wall panel construction. This survey uncovered poor-quality construction with varying thickness depths that could lead to structural safety issues.
In addition to these safety elements, the premises were experiencing rising maintenance costs, poor thermal efficiency and relatively high service charges associated with an ageing building. The numerous safety concerns highlighted the need for projects to address and mitigate risks for the tenants' safety and the premises' long-term viability.
The risks and consequences of fire presented a genuine concern. LPS structures are not inherently more likely to have a fire compared to other types of buildings. However, due to their unique design and construction, LPS structures are more vulnerable to the threat of fire and explosions which can lead to full or partial collapse, as witnessed with the Ronan Point disaster.
RBC identified this risk and implemented measures to eliminate the risk of local explosions. Whilst the future of the blocks was being decided, a fire watch process was implemented; this allowed RBC to ensure that no natural gas heating systems, oxygen canisters and any other high-fire risk items were allowed onto the premises.
The fire watch process regularly reviewed the housing units and communal areas for fire risks, removing debris and combustible materials before they had a chance to accumulate. The fire watch process also acted as a control system for anything entering the premises. The fire watch officers were present to challenge contractors, deliveries and residents attempting to bring in items that could compromise fire safety.
RBC supported tenants by providing electric heaters and prioritising the decant of high-risk tenants needing oxygen to support healthy living.
What triggered the projects?
It was apparent that the LPS method presented very real risks for building and structural safety. Through a rigorous and routine inspection programme, RBC quickly identified that the ‘as built’ information did not portray the actual quality of the construction methods.
The 2017 intrusive survey raised serious concerns about structural safety and provided limited assurance that the construction methods were sound and of high quality. RBC’s thorough inspection programme quickly highlighted the building’s quality degradation and triggered further inspection, ultimately revealing the safety issues.
The intrusive survey emphasised the necessity for change.
This highlights the need for authorities to have scheduled inspections in place and to treat the findings seriously, being prepared to carry out further investigation or to take action.
Highlighting the change
RBC carried out costing exercises for both the refurbishment of the blocks and the demolition and redevelopment. The demolition and redevelopment option presented the need for only approximately 10 per cent more funding and was selected as the preferred option by RBC.
Additional benefits were realised through the redevelopment option, including the following:
- the provision of 18 additional dwellings providing over 300 homes
- 100–120-year life for structural elements, as opposed to the 20-year remaining life for the existing buildings
- new homes will be an EPC rating of ‘A’ as opposed to ‘E’ for the existing units
- more sustainable development, including adding measures to increase biodiversity and carbon reduction methods.
The development scheme removed any safety risks by demolishing the aged buildings. The new development will construct homes fit for the future that meet all current safety regulations, are thermally efficient, and are affordable with minimal service charges, maintenance and running costs.
Lessons learned
RBC demonstrated a high commitment to routine inspections and were prepared to conduct further investigations and act on recommendations.
This proactive approach highlighted potentially significant safety concerns at an early stage, which paved the way for a modern and successful development improving the quality of social housing for the residents of Rugby.
The intrusive survey process demonstrated that ‘as built’ information for LPS premises should be verified. The risk of a full or partial collapse of LPS buildings is too significant to simply infer that the building is safe from outdated and unreliable sources.