Building and engineering products group Alumasc said it had made a good start to the new financial year and maintained the momentum of the previous 12 months. Revenues have tracked slightly ahead of last year's levels since the start of July and it reported further expansion in its operating margins. The margin growth has been driven partly by a strong performance from its rainwater and drainage brands, improving results from its roofing business and narrowing losses at its Alumasc Precision division, the company said.It added: "In view of the positive trends remaining as before, the board's expectations for the full year are unchanged."Net debt so far this financial year has been on average £3m lower than a year ago.Its order book has dropped to £36m from £44m at the end of June following the delivery of work on a large order in Canada.Shares in the company were flat at 135p in 15:45 on Thursday.TB