I have a back to back end of terraced property. I want to put a single storey, standard construction lean to extension on the side. what I would like help with is wether I need planning permission or just regs to build a 3m out from the side of the house and 4.2 m back along the side. I understand the heights and boundary laws, just the overall size issue. Can anyone help me?! As i have no back of property and no other buildings or never been extended, can i pay and crack on?!