Anyone done one and how problematic is it? We have a very slopey roof on edwardian semi, and really need to do a hip to gable plus dormer at back to have a double bedroom and ensuite. Some houses very simillar have a gable end already from time of their construction, so would planners be ok if our semi doesnt match the other half but looks more similar to other houses on the streer. Without doing the hip to gable we might get a small double with no bathroom and not sure if it is worth it. Is it worth getting an architect to come up with a clever idea?