Engineers in North Yorkshire have been forced to condemn a row of terraced houses after heavy rain caused a retaining wall to fail. Saturated land from a week of heavy rain caused the landslip in the gardens of five properties on Aelfelda Terrace in Whitby.
“The slip itself is not that big,” said Halcrow earth engineering and sciences director Roger Moore. “Part of the problem is an old ad-hoc retaining structure.”
Moore is a technical advisor to Scarborough Council. Scarborough’s structural engineers and local building control officers from North Yorkshire County Council advised that houses three to seven be demolished to prevent damage to other buildings.
The Victorian-era terraced houses sit on a steep slope overlooking the River Esk on Whitby harbour. A build-up of groundwater from the severe rain caused the landslip overnight on 26 November.
Following detailed inspections by structural engineers and North Yorkshire Building Control, Scarborough Council decided to demolish the five terraced houses to prevent them crashing into properties further down the slope.
Moore said the ground conditions in the area made the slope prone to landslips.
“It is fairly weak glacial sediments overlying interbedded sandstone and mudrocks,” he said. Along with the poor soil conditions, the area is prone to landslips from erosion from the River Esk, according to Moore.
“In effect the whole harbour is a coastal slope,” he said. The harbour area was developed in Victorian times and built up with varying degrees of retaining walls.
The council has appointed contractor Transcore and its subcontractor RGS to carry out the demolition. English Heritage is advising on the demolition.
Heavy machinery cannot be used on the site due to its instability and inaccessibility.