A form of concrete prone to sudden collapse has been found at flats in Southampton, according to a news report.

The Telegraph has reported that reinforced autoclaved aerated concrete, known as RAAC, was present in planks which formed 'both supporting and internal walls of the property'.

The paper has not disclosed which block of flats it is - but describes the building as being built in the 1970s and currently in use by residents.

READ MORE: What is Raac and what buildings has it been used in besides schools?

According to paperwork seen by the national paper, cracks are visible in these planks and they are beyond their 30 year lifespan.

This information came from a 'source familiar with the property', the Telegraph said.

Speaking to the paper, the source said: “The life expectancy of this concrete is 30 years, and it’s been nearly 50 years.
“The planks could potentially collapse without demonstrating signs of distress, as we’ve seen in schools.
“But these planks already have cracks, and they’re not even safe enough to repair. It needs to be condemned.”

This comes as Mason Moor Primary School, which was closed yesterday due to a RAAC inspection, confirmed none of the potentially hazardous material was present in their buildings - meaning the school can hopefully reopen sooner than the planned date next week.

Southampton City Council has confirmed that RAAC has been found in the outbuilding of another school - but has not said so far which school this is.

RAAC is less durable than concrete, and is prone to collapse when wet, as moisture soaks into its aerated holes.

Buildings built between the 1950s to the 1990s that have not been assessed by a structural engineer could be at risk of collapse.

The council has been approached to confirm which block of flats and which school has RAAC in it.