The builder of a $73 million public project that collapsed mid-construction has been telling clients for six months that faulty design was to blame for the potentially fatal accident, a claim its inner-Melbourne council client has now called out as unproven and “simply not supported”.

The steel-trussed roof structure of the Kew Recreation Centre in Melbourne’s inner east collapsed on October 20 last year, and in a letter sent to at least one other client in March this year Adco Constructions said it commissioned a structural engineer’s report that found it was not to blame.