At the back of our house, is our bathroom, which has a flat roof. Between the outside wall, and the back lane wall, we have some decking. Now, we would like to put decking on our flat roof, to use as a sundeck, with of course, handrails etc. We want to put a staircase(only about 3 steps) from our current decking to the new decking. Do we need planning permission for the new decking, as it will mean it will overlook our neighbours garden(and we don't get on with them). There are at least 5 houses in our street which have this done, and we can guarantee that as soon we start, the neighbours will complain.