Webster will start his sabbatical on November 2 and return to work on January 28 next year.
During this period the group will continue to operate as three integrated reporting regions, led at Board level by Derek Pitcher (Europe and MEAI) and Kim Berry (Asia Pacific), respectively.
The executive responsibilities which would otherwise be handled by the CEO will lie with Pitcher.
Sweett issued a profit warning to the City in June and launched a cost-cutting drive last year which is expected to deliver £2m in annual savings.
Sweett will be publishing its results for the six months ended 30 September 2012 on Friday November 23.