Party Wall

Unless restricted by a conveyance, transfer, or a party wall agreement, either owner can add to, alter, or repair the wall. In doing so, the owner must not damage the adjoining property or impair the easement to which the owner is entitled.

Either party, for example, may increase the height of the wall, provided the increase does not diminish its strength. Similarly either party may underpin the wall and sink the foundation deeper or increase the thickness of the wall by adding to it on his own land.