If talking about a general contractor then he/she is someone who undertakes construction projects of any size, new... moreIf talking about a general contractor then he/she is someone who undertakes construction projects of any size, new buildings, additions, or alterations to existing ones. Managers of such building projects typically employ Plumbing contractors in London or subcontractors to carry out the actual building. They are also in charge of sourcing all the project's materials. The general contractor oversees the project and keeping everyone on the same page.