Following the award of our first official contract as part of the Trust’s extensive estates and maintenance programme, we have successfully delivered a variety of projects of around £18m in total including initial remedial works (temporary propping, timber end bearing supports), main failsafe support works, RAAC panel works and anode installations around the hospital.

Reinforced Autoclaved Aerated Concrete (RAAC)
RAAC is a lightweight form of pre-cast concrete, which gained prevalence in the 1950’s and was commonly used in the construction of roof and wall panels in schools, offices and hospitals until the mid-1980’s.

It differs from standard concrete during the production process where a fine aggregate and gas producing chemicals to create bubbles in the mix which are cured using heat, with no coarse aggregate used.

Some key issues with RAAC, which are currently being brought into the spotlight include:

• Relatively weak bond formed between concrete and metal reinforcement
• Inadequate length of steel reinforcement, resulting in shearing to panel
• Very high span to depth ratio
• Poor aggregate mix
• Corrosion to metal reinforcement, due to failure in the performance of roof membranes
• Excessive and progressive deflection associated with widespread hairline cracking
• Cracking resulting from moisture and temperature related movements in the planks
• Roof planks acting independently, as opposed to a single structure

The specialist works that we have completed to date have served to strengthen the existing building and preserve its structure ahead of its re-location to the new facility on the Hardwick Manor site in 2030.

Challenges Faced and How we added value
Given the specialist nature of the works, we encountered several challenges requiring a swift resolution from our delivery team. This included:

• Minimising Disruption to the Live Hospital: We established a regular and effective communication protocol with the Trust’s Estates Team and developed carefully considered phasing plans tailored around the daily operations and specific requirements of the hospital.
• Ensuring Patient Privacy: We incorporated vision film to courtyard windows to ensure that works could be carried out to the required sequence and provide the patients with the required level of privacy.
• Adapting Access Requirements: We overcame the initial realisation that our proposed access strategy, of mobile tower scaffolds, would elongate the process, given the extensive time required to continuously dismantle and re-locate the tower to the next wall panel. We added value and found greater success in erecting a scaffold system, which was trialled in one courtyard and continued future phases to optimise programme outcomes.
• Developing Quality Assurance Procedures: We developed a quality assurance system that gave each RAAC panel a unique identification number and checking sheet, to ensure that all corresponding documentation could be clearly linked to the specific panel. This process was agreed post-commencement and following a trial of various alternative methods and detailed discussions with all relevant stakeholders.

We are extremely proud of all elements of our RAAC panel works at West Suffolk Hospital and thoroughly believe that the expert knowledge we have gained through the delivery of all relevant projects can be applied across sectors to assist with the growing concerns associated with the presence of RAAC panels.

We are delighted to have the opportunity to continue delivering projects at West Suffolk Hospital in the future and, following a recent contract award, be extending our specialist knowledge and experience to Queens Hospital in Kings Lynn, who are continuing their own RAAC panel structure and support works.