I have recently had a flat roof re-felted, but whereas the original felt overlapped the gutter so that rain water ran straight into the gutter, the company who re-felted has left the felt short so that rain water runs down BEHIND the gutter onto the ground, windows and doors. Obviously I have asked them back but that was three weks ago and I have not seen them since. This is not some cowboy company but a local firm run by somebody I have know since birth and I think it is only pressure of work that stops him coming. However I would like to get this solved as soon as. My question is, is there such a thing as extension pieces that clip onto the edge of a gutter to extend the height of the sides. I am sure that this would solve the problem.