[DiverDude]

That house looks pretty new so I'd be asking some questions about who goofed on the surveying.

Regardless, I'd look into the possibility of an easement. There has to be a limit butfor the sake of 5cm, it seems extreme.

When my neighbor sold his house, the city forced him to re-survey it and it was determined that his fence wasn't quite straight and one end was something like 5 inches onto my property. Now I know this isn't a FIRE issue, but I granted him and easement for the fence and the problem was solved. Had I not done that though, he would have had to either pay me to give in or tear down the fence.

Did the house design show bedrooms in the basement ? A window is required for egress in basement bedrooms so you'd have even more ammo against the builder because you wouldn't be able to move the window because you'd need it for the bedroom.

Bottom line is that the window thing should be someone else's problem; not yours.