My neighbour in north london is about to build a loft conversion with the dormer cheeks flashed over the party wall and cut-outs from the party wall for loadbearing purposes. They say they dont need planning permission for this even though the previous owner build a back extension etc. I am concerned as i havent seen any building regs certs and my party wall surveyor seems to be going along with their plans. I may want to build in the future and am worried that their works will make my loft conversion more problematic. What should i do?
Your adjoining neighbour may be building their loft conversion within their permitted development rights and as a result full planning permission may not be required. This can be easily confirmed either on your local authority website or by calling your local authority Planning Department. Assuming the neighbour is constructing a rear dormer, the dormer cheek ( triangular side section ) must not be built past the centre of the dividing wall ( on your half ), however it is standard practice to use a code 4 lead flashing to cap over the top of the dividing wall to ensure a water tight seal. As with the construction of the dormer, the load bearing beams cut into the dividing wall must not project past the centre of the shared wall. I would advise you to study a copy of the plans and approval from Building Control prior to commencement of the works. As long as the neighbours structure does not encroach past the centre of the dividing wall you will have no difficulty building your own loft conversion at a later date, a standard method is used to join the dormer windows together to comply with fire regulations.
It would be standard practise for a Party Wall Surveyor to check all of the above when they are preparing the Party Wall Award.