Private House, Glastonbury, Somerset
Approved Installer: Premier Construction Ltd
Client: Royal Insurance
 
  PROBLEM

In 1995 this property, built on the side of a steep hill of clay overlaying rock, was suffering from masonry cracking due to widespread ground movement.

The main building, on stepped footings, was separating from a rear extension, built on a concrete slab, and moving down the hill.

The front corner of the building had fallen away due to subsidence, caused by an adjacent tree, and vertical cracks were running from the upper windows to the DPC. There appeared to be no obvious practical options as piling or mass underpinning were likely to disturb the footings and accelerate movement. The owners and insurers needed to find a cost-effective solution.

  SOLUTION

In one of the first insurance-backed Helibeam repair programmes, pairs of stainless steel HeliBars were grouted into five specified mortar beds around all sides of the main structure and its extension to create deep masonry beams: two above the DPC, two under the upper storey windows and one under the eaves, with grouted CemTies installed on the internal corner.

The whole structure was reinforced and secured as one unit while loads were redistributed allowing the masonry to bridge over areas of subsidence. Individual cracks were stitched with concealed grouted HeliBars.

Differential movement was arrested, integrity was reinstated, future cracking and small cyclical movements prevented and all repairs were hidden. The property regained insurable status, was mortgageable and was sold and over 10 years later no further problems had occurred.