Architects Paul Robinson and Laurence Bowen start on a project that is going to push them in a completely new direction - a state-of-the-art factory-built house. If all goes to plan then this incredible structure will go up in just five days, but even getting it on site turns out to be more tricky than anyone had anticipated.

And in Radlett, Hertfordshire, local architect Bob Thompson tackles the design of a new extension to a 1950s house. Will client David be able to deal with the responsibility of managing the whole project himself? Show less