£48,417

is the value you can add to your home in just seven days, a new survey shows. Research by the Federation of Master Builders (FMB) and Homeowners Alliance (HOA) indicates that removing an internal wall to create an open-plan kitchen-diner could add up to £48,417 to the average London home. Surrey residents can benefit from a boost worth £35,611 by building a garden room; and a kitchen overhaul with new flooring, worktops and cabinets could increase the value of a house in Dorset by £26,838.