Background
A pair of semi-detached houses, freehold. One house is longer than the other. Shorter house is midway through constructing a wooden structure over their patio. Not sure what to call it, it's a tasteful permanent rain shelter over the patio, maybe a gazebo.
The structure has 2 sides formed by rear wall of shorter house and side wall of longer house, no walls on the other 2 sides, vertical wooden posts support sloping beams each maybe a metre apart to form the roof which slopes from the back wall of the shorter house down to the end of the patio, it will have a wood, perspex or glass roof supported by these sloping beams. Height of the structure is approx 3 metres at the highest point, so where it joins the wall of the constructor's own house. It's a DIY project.
Key points and questions
Constructor has drilled into the exterior of the longer house's brick side wall to affix part of the wooden structure.
Constructor informed longer house owner that work was about to start, didn't formally ask permission, longer house owner didn't explicitly disagree or agree.
I have read party wall information and don't understand it well enough. My questions are:
- Is a party wall agreement or other permission needed or helpful?
- If "yes" and if this isn't in place, will it affect either owner's ease of selling their house in the next few months or years?
- If the longer house owner hasn't objected yet, how long until it is too late to object?
- Anything else to think about to protect the interests of both house owners and to maintain a good relationship?
Thank you for knowledge you may have. Once I have read it, I can seek formal advice from a surveyor or solicitor. Even better if it becomes clear that party wall agreements are irrelevant to this situation.