In recent news, the dangers of RAAC within public sector buildings have been highlighted across the UK. Considered to be an innovative solution within the construction industry, The Standing Committee on Structural Safety (SCOSS) report issued in May 2019 (https://www.cross-safety.org/sites/default/files/2019-05/failure-reinforced-autoclaved-aerated-concrete-planks.pdf ) highlights the significant risk of failure in RAAC.
In this article we explore what is RAAC, what is being done across the UK to overcome potential risks and how scaffolding is an important aspect when dealing with RAAC in buildings.
What is RAAC?
RAAC is a lightweight form of precast concrete, which was used often in public sector buildings in the UK. It was mostly used from the 1960’s to the 1990’s. During this time, RAAC was considered an innovative construction material. What makes RAAC different to normal, dense concrete is the lack of coarse aggregate, and is instead made in factories using fine aggregate, chemicals and heat.
Why was RAAC used?
In comparison to traditional methods, RAAC was relatively lightweight, which made transportation, lifting and handling easier, and reduced the load to supporting structures. Although RAAC has good thermal properties and good fire resistance, it is susceptible to moisture and water, causing corrosion of the embedded reinforcement.
Why is RAAC a safety risk?
Whilst RAAC is light, its composition makes it less durable than traditional concrete, also having a lower loading capacity. RAAC has an estimated life span of around 30 years, according to gov.wales. This along with being susceptible to the elements causing corrosion, poses risks to buildings it was used in.
What is being done about RAAC?
In August, the government announced the closure of several buildings, whilst it worked to increase the number of temporary buildings to accommodate students and teachers, during this period the School Rebuilding Programme has been launched.
RAAC is prone to collapse without warning, therefore full removal is considered the safest option.
Why is Scaffolding essential when dealing with RAAC?
According to a blog found on the .gov website (https://educationhub.blog.gov.uk/2023/09/19/new-guidance-on-raac-in-education-settings/ ) RAAC is commonly found as precast panels in roofs, commonly in flat roofs, and occasionally in floors and walls. Scaffolding becomes an essential element when tackling RAAC within public sector buildings. How exactly can scaffolding assist in this time-critical matter? This will differ from case to case, depending on the complexity of the building, scaffolding provides workers safe access in order to work from heights. Works may consist of back propped support and containment scaffolding, especially if demolition works need to commence. You can see an example of works like this at our Broadwater Farm case study here:
https://innercityscaffolding.co.uk/case-studies/broadwater-farm/
If you require expert scaffolding services to assist with RAAC inspection, propping or removal, please do not hesitate to contact one of our team on 01708 932304, or email info@innercityscaffolding.co.uk
Sources:
The concrete crisis: what’s being done to address RAAC risks?
https://educationhub.blog.gov.uk/2023/09/19/new-guidance-on-raac-in-education-settings/
https://www.scotsman.com/education/what-is-raac-why-was-the-concrete-used-to-build-schools-and-hospitals-across-much-of-scotland-4280363
https://www.cross-safety.org/uk/safety-information/cross-theme-page/structural-safety-reinforced-autoclaved-aerated-concrete-raac-planks
https://www.theguardian.com/education/2023/sep/19/schools-england-raac-reinforced-autoclaved-aerated-concrete
https://www.lboro.ac.uk/news-events/news/2023/march/reinforced-autoclaved-aerated–concrete-raac/
https://www.telegraph.co.uk/news/2023/09/19/what-is-raac-concrete-why-dangerous-schools-close/
https://www.gov.wales/reinforced-autoclaved-aerated-concrete-raac-frequently-asked-questions
