Builders merchant and DIY group Grafton has completed the acquisition of Crescent Building Supplies, a general merchant business trading from three branches in West London and one in Berkshire.The addition of Crescent, which generated revenue of £10.5m in the financial year to 31 March, will improve Grafton's coverage of the merchant market in West London and South East England.Shares in the FTSE 250 group inched higher at the opening bell.