Hi AMB,

I see your dilemma. I don't have first experience of your situation so I'm not sure if my comments will be of any help but I'm going to be starting a loft conversion too next month and I'm in an edwardian terrace ( one neighbour already has a loft done ). From my experience, it is best to casually speak to your neighbour about your future intentions because when the time comes you will have to ask them to sign a Party Wall Agreement anyway.

Just a few questions -

Is the dormer side/cheek built right up to the boundary/party wall? If yes and you want to maximise the size of your dormer, do you plan to join your dormer with your neighbour's dormer if they agree to block out window? If neighbour does not allow you to join onto their dormer, you will have to build the dormer 500mm in from Party Wall because the builder needs space to tile the dormer side ( so your loft will not be so wide ). This is the dilemma we had but luckily our neighbours agreed to join onto theirs. You may wish to speak to a builder about this 500mm gap but that it what our architect and builder told us.

I'm not an expert on the 'right to light' but if you neighbour already has another window and if you decide to build within your boundary I don't see why it should stop you, I assume you are doing it through the Permitted Development route?

Do you also have a chimney stack at the back?

Have you met your neighbours? It's a bit of a tricky situation because you haven't bought the property yet and you don't know what they are like. I don't think it matters their window overlooks your roof as they will just get a view your tiles and you can't see into their window, they should have thought about that before they built their dormer. Did they build it a long time ago?

Just to add to that, my neighbour has their loft bathroom extractor fan facing our roof ( so similar to your window situation ) but they have agreed to move it ( at our cost ) as we want to join onto their dormer leaving no gap in between the dormers, otherwise we would have to build 500mm from Party Wall leaving us with a smaller loft.

It might be worth arranging an appointment with estate agent, you and an experience building company that does a lot of lofts to get a ball park quote for a loft conversion and you can ask the builder questions there and then. Hopefully getting an experienced company doing lofts might give you advice on how to deal with this. They might have even had a similar situation before.

Is there anyone else out there who can provide me with some advice? I am yet to exchange contracts but it is a genuine worry and putting me off the purchase.