Consider a terrace of three two-storey houses
We own the middle house, numbered 2 on the diagram. The upstairs is slightly larger than the downstairs, because there is an alley (exclusive to our house, with a door on the front) which gives us access between the front and back of the house.
Our neighbour believes that our side of the shared ground-floor wall, between our alley and his house, is "owned by the council" (he is a tenant in a housing association house, we own our house) and that we should not do anything to that wall such as paint it, stack firewood and bags of coal against it or hang objects from nails/hooks in that wall.
This sounds absurd. My understanding is that, irrespective of ownership of boundaries as set out in deeds, you are allowed to paint, stack against etc, as long as you don't cause any damage - if I drilled into it and disturbed the plaster in his house or if things stacked against it caused damp, that would be a problem. But normal usage is different.
Who is right? I'm trying to get the housing association to give a definitive answer of their understanding, to be able to quote to him, but I think this goes beyond the fact that his house happens to be owned by a housing association rather than him. If what he was saying was true, you'd not be allowed to paint your own bedroom wall or hang pictures on it because it happened to be shared with the neighbour!
What are the normal rules about shared walls? I know with boundary fences/hedges, it is defined in the deeds which house is responsible for which wall. But what about shared internal walls? Is there any difference because the space on our side of the wall is an alley rather than a habitable room?