Registered engineers will have to be appointed to monitor construction of high-risk structures on small village houses under new control measures introduced today. But the measures, proposed after the collapse of a balcony at Swallow Garden, Fanling, in December, were attacked yesterday as unfair and problematic. Director of Buildings Choi Yu-leuk said the measures, supported by the Hong Kong Institution of Engineers and Heung Yee Kuk, would add about $80,000 - or 10 per cent - to the cost of building a small house. Under the new measures, a registered structural or professional engineer must monitor construction of balconies and canopies. A person with a specified qualification and work experience will have to be appointed to supervise construction of the entire house. On completion, the engineers and supervisor will have to sign a construction completion report. Additional safety conditions will be attached to criteria needed for exemption from the department's safety checks, which developers can enjoy under the 'small house' policy. The Lands Department, which inspects the building process, admitted it had to rely on engineers' judgment as it did not have the expertise to make final technical checks on completed houses. But it can refuse to issue a satisfaction certificate if it finds the contractors have failed to follow the new guidelines. The Government is also reviewing the Buildings Ordinance to see if there is a need to further tighten controls on small houses in the long term. Dr Choi said the measures could not be applied to the 1,000 small village houses already under construction. But surveyor David Chan Wah-wai said the monitoring system was problematic with contractors exempted from signing the completion report as legal liability problems might arise in case of an accident. He said the independence of the construction supervisors would be undermined if they were hired by the contractor. But Dr Choi said: 'If the two parties [the engineers and the supervisor] fail to do a proper check, we can easily identify who should be held responsible in case of an accident and take action in accordance with the Buildings Ordinance.' The report on the Swallow Garden balcony collapse released yesterday said a wrongly bent reinforcing bar, existence of a construction joint and a concave area between a beam and the balcony slab were possible causes. Dr Choi said he would study if any parties should be held responsible.