It will be built on the car park behind the posts and will feature six RFU approved changing rooms as well as changing for male and female officials.
There will be a community room capable of multi-use and able to accommodate up to 200 peope for a dinner or similar function together with club bar, kitchen and a fitness room to house the existing gym equipment.
Site investigations will begin within the next few weeks and at the same time the architects, Smith Smalley of Harrogate, will seek to obtain full planning permission - the project already has outline permission.
The successful tender should be announced in the autumn with a start date in October and completion in mid-2014.
Club Chairman Peter Olsen says:"This is the start of a whole new chapter in the history of the club.
"The developoment we have planned will sustain rugby at West for years to come, and it was appropriate that the decision was taken at a board meeting which welcomed two new young members in players Chris Young and Martin Todd."
More details of the project and plans for extra fundraising will follow.
