A case study focusing on how Southwark Council took action on four Large Panel System buildings in their estate, and ensured residents were engaged and informed throughout this process.
Summary
Buildings constructed using Large Panel System (LPS) methods lack structural integrity and must be assessed by owners as a matter of urgency. One of the key challenges that local authorities face in this process is keeping residents and stakeholders informed and engaged as difficult decisions are addressed to keep residents safe. Southwark Council took action on four LPS buildings in their estate, and ensured residents were engaged and informed throughout this process.
Introduction
Southwark Council owned four precast concrete large panel system (LPS) 14-storey tower blocks which are situated within the Ledbury Estate. The four tower blocks were built by Taylor Woodrow for the Greater London Council between 1968 and 1970 and transferred to Southwark Council’s ownership in the early 1980s.
The LPS construction method has led to national concerns over the years with the risk of partial or full collapse inherent in the nature of the construction. LPS constructions are at particular risk of collapse from internal gas explosions. This risk was tragically realised in May 1968 when the Ronan Point tower block suffered a partial collapse as a result of an internal gas explosion.
The damage caused to Ronan Point that day was considered to be more than expected following an explosion of that magnitude leading to a government-led reappraisal of LPS blocks throughout the UK. This led to a number of Ministry of Housing issued circulars and amendments to the building regulations and national wind code.
In addition to these amendments, the Building Research Establishment (BRE) published several reports following the Ronan Point Incident. The reports included a 1985 report that focussed on Taylor Woodrow Constructions in which the Ledbury Estate was referenced. The report commented on the construction and the importance of checking the flank wall joints and general strengthening of the construction.
Southwark Council regularly carried out visual inspections of the properties which did not highlight any concerns. However, in 2017, following the tragic events of the Grenfell Tower disaster, the residents raised concerns about fire safety on the estate and requested assurance around the safety of the building.
The risk that needed to be addressed
To support the assurances required to the residents, Southwark Council undertook an urgent investigation; supported by structural engineers, Arup. This investigation uncovered the following findings:
- The structure of the building was in generally good condition with no significant deterioration to the concrete or steel construction.
- The structure of each building met with the revised wind loading requirements defined by the current building codes
- Strengthening works had not been completed as previously thought, meaning the blocks did not comply with the amended BRE guidance for the prevention of disproportionate collapse.
This left the blocks particularly vulnerable to internal explosions which could trigger an event similar to the Ronan Point collapse.
Following the Grenfell tragedy, residents were very concerned about their safety which led to an immediate need for assurance and action.
Highlighting the change
Immediate action was required to provide a safe building for residents. In August 2017 the council immediately removed piped gas from the blocks to reduce the risk of explosion. This led to a lack of heating, hot water and cooking facilities for most tenants. As part of the planned project to support tenants through this change electric cookers and alternative heating were gifted to residents who had been impacted by the loss of gas to the buildings.
The council quickly built an in-house 24/7 local Ledbury Estate team to work with the residents to keep the building safe and to provide assurance and support for residents whilst they waited for the installation of an upgraded fire alarm and monitoring system.
The Ledbury Estate team, alongside the authority leads, established a joint assurance meeting process. With the residents providing an opportunity to provide updates regularly and to set new fire safety processes for the blocks, including:
- a walking fire watch on every floor,
- zero tolerance for combustibles in common areas,
- refreshing the emergency evacuation procedures,
- works to temporarily seal cracks and gaps.
Southwark Council’s engagement process was very successful in providing assurance to the tenants of fire safety as they built plans for the future of the Ledbury Estate. The Ledbury Estate team, within the council, received very clear direction from the Council Members that the future of the estate must be designed and led by the residents. This paved the way for a resident-led decision on the estate’s future.
After receiving architectural and structural information on what is possible for the estate, four clear options were presented to the residents by the Council Ledbury Estate team, including:
- Option A - Strengthening of the blocks,
- Option B - strengthening, refurbishment and infilling areas to create more housing,
- Option C - a blend of strengthening and new build,
- Option D - demolition and new build.
The residents eventually settled on the option to demolish and provide new housing, beginning a redevelopment of the Ledbury Estate which will provide not only 224 replacement homes but also more than 100 new additional homes, built to meet current safety and efficiency regulations.
The engagement between the council and the residents helped to quickly address the initial safety concerns and create a resident-led development that will greatly improve the living conditions on the estate. This was achieved through excellent communication and engagement methods and a truly collaborative approach to the issues.
The council designed several bespoke processes to support the tenants, including:
- providing a 24-hour on-site team who support residents with easy-to-access day-to-day housing management and support for the vulnerable
- weekly information newsletters, constantly providing clear and transparent communication to the tenants
- two fire wardens per block who support the fire safety processes, ensuring bottled gas and oxygen are not brought out on site, monitoring of contractors, and a visual indicator to tenants that the council are in full support
- visual fire evacuation and information guidance to help tenants clearly understand what to do to support fire safety, including posters, information booklets and fridge magnets.
The decision on the future for the blocks was determined by a tenants’ ballot which met the need for a decision to be made by the community who live in the blocks, and the former tenants with a right to return. The ballot was carried out by an independent tenant and homeowner advisory organisation and was completely anonymous.
The ballot was decided on a simple majority, based on one vote per household, with no minimum turnout. The residents were provided with clear and transparent information on which to decide. The strength of this process helped gain tenant engagement with most households voting on the future of the estate, aiding a decision that would better benefit the community.
Lessons Learned
Southwark Council demonstrated a high level of commitment in engaging with tenants through a particularly challenging time. The open and transparent approach helped tenants to understand the risks, the required safety measures, and the possible future for the Ledbury Estates.
The level of engagement with tenants helped to improve the safety of the blocks whilst a decision was made. The tenants supported the council with fire safety, leading to a joint effort to remove hazards and prevent the build-up of debris.
The council’s approach in providing dedicated fire safety and an on-site support team, demonstrated its commitment of change to the tenants, and was available to provide easy-to-access support during a difficult time.
The council’s approach to using void units for intrusive structural inspection demonstrated that building owners should not make assumptions about LPS safety.
It is dangerous to assume past efforts at strengthening and safety measures have been successful. The council’s decision to engage with structural engineers, with a thorough knowledge of LPS construction, uncovered safety issues that could have remained hidden.