Construction consultant John Rowan & Partners and Walker Sime, a project manager and quantity surveyor, have formed an alliance.
Stephen Gee, John Rowan's managing partner, said the rationale behind the alliance was to expand into the north of England.
He said: "We have made a commitment to increase our business in the North and we expect our agreement with Walker Sime to play an important role in delivering that growth."
The plan is that while John Rowan is able to offer its clients in the North more support from the Manchester-based Walker Sime, the latter will benefit from John Rowan's presence in southern England.
John Rowan expects to reach a £3.6m turnover at its year-end in April, which is twice Walter Sime's £1.8m turnover in 2005.
John Rowan made the approach to Walker Sime because it wanted to be seen as a national company rather than just a southern-based regional consultant.
Gee, who stood for the Liberal Democrats at last year's general election, said: "It was important that we shared similar cultures and values so we carried our a series of meetings and exercises before drawing up the agreement."
We expect our agreement to help deliver growth
Stephen Gee, John Rowan
The alliance does not preclude either company from bidding for new business independently of the other.
Derek Walker, partner at Walker Sime, said: "As a company we have ambitions to double in size and we expect this relationship to play an important part in underpinning that growth."
Both companies work in the residential and hotel sectors. John Rowan also works in the retail sector, whereas Walker Sime also has commercial, leisure and distribution work.
Gee said the tie-up with Walker Sime would be of immediate benefit for its client De Vere Hotels, which is based in Warrington, as John Rowan could use the Manchester office as a base.