Boundary (party) walls or fences
In the absence of proof that a boundary wall, fence or hedge is entirely on one of two adjoining properties, it is presumed to be half on one property and half on the other. Some legal authorities state that each part is separately owned by the owner of the property on which it stands, but that there are reciprocal servitudes of support. Other authorities state that the wall is owned jointly by the owners of the adjoining properties. The law relating to such encroaching boundary walls reflects the influence of both theories. An owner who transfers his or her property, automatically transfers the joint ownership. Neither owner may, without the consent of the other remove, raise or lower the boundary wall or tamper with it in any way except in an emergency, although in terms of common law a neighbour is allowed to break down a wooden fence and replace it at own cost with a more expensive partition.
Either owner may re-erect a boundary wall destroyed by an act of God, such as fire or flood; the other owner would have to contribute half the cost - if he or she will derive any benefit from it. Each owner is obliged to contribute to the maintenance and repair of the wall, although an owner can refuse to contribute to the cost of an unreasonably expensive new wall. Moreover, an owner is under no obligation to replace with a similar structure a boundary wall that was unreasonably expensive when it was originally erected.
It is best to come to an agreement with your neighbour on the amount to be spent on the wall. Although both of you would be entitled to reasonable use of the boundary wall, fence or hedge, this right does not include reducing its strength or making it unstable. It does, however, include improving and altering the appearance of the side that fronts your property. Subject to local-authority regulations, you may use your side of the boundary wall as support for a beam or for water pipes. If it is strong enough, you may even build on it.
