My Neighbour has Built Their New Dormer on Top of the Party Wall

by: The Party Wall Surveyor


We signed a party wall agreement for my neighbour to build a dormer for his loft conversion. However, the work is now finished and we have realised that the dormer has encroached by about 5 inches over the boundary. Now we want to convert our loft and this encroachment is going to cause us problems. Do we have a right to remove, or to ask him to remove, any parts of his building which come over our side of the boundary line? I have also been told that this encroachment will devalue our property.


I cannot comment in any detail on the encroachment issue as that is a boundary dispute rather than a party wall matter.

As it is the side of a dormer that is encroaching presumably it is sitting over the party wall. Section 2(2)(h) gives you the right to cut away any part of an Adjoining Owner’s building that is overhanging a party wall. You will need to serve the relevant notice to exercise that right and you would generally be responsible for the costs of making good your neighbour’s property following your work.