NINE sites in every one hundred are unsafe because of poorly fixed cladding anchor installations.
A survey carried out by Leicestershirebased Independent Fixing Consultants revealed that mechanical and resin anchors failed on almost 9 per cent of sites where proof tests had been carried out.
A five year study reported anchor failure on 16 of 182 sites where proof tests were carried out. On those 16 sites 15 per cent of the anchors failed tests.
The failures covered both resin fixed and mechanical anchors, with resin fixed anchors used on 12 of the failed sites and mechanical anchors on four.
According to the report the majority of the failed cases were due to human error with poor hole cleaning, inadequate resin injection and both over and under anchor tightening cited as the main reasons for failure.
Industry representative the Construction Fixings Association claimed that contractors must train and supervise installers or face a rash of accidents.
CFA chairman Paul Langford said: 'Most of these anchors were for safety critical applications where failure could have caused loss of life or heavy financial penalties.
Many jobs are poorly carried out but do not come to light because of the conservative safety margins built in to the allowable loads.'
Mr Langford also called for the use of anchors carrying European Technical Approvals to help combat the failures.