The easiest way to determine the boundaries between properties is to consult the official town planning diagrams kept by the local authority in control of the area. In the event of a dispute over the dividing line between two properties, the first point of reference would be the official property plans (diagrams). One can refer to the title deeds of the properties concerned to ascertain plan numbers and with which deeds the plans are filed.

In the absence of proof that a boundary wall or fence 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 jointly owned by the owners of the adjoining properties.

It is important to take note that the law relating to such encroaching boundary walls reflects the influence of both trains of thought and does not concretely swing in either direction. An owner who transfers his property automatically transfers his 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 my 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. Also, an owner is under no obligation to replace with a similar structure a boundary wall that was unreasonably expensive when it was originally erected.

Although both parties are entitled to reasonable use of the boundary wall, this right does not include reducing its strength or making it unstable but does however include improving and altering the appearance of the side that fronts your property. Subject to local authority regulations, either owner my use his side of the boundary wall as support or a beam or for water pipes and may even build on it if it is strong enough.

Title deeds might determine who is responsible for repairing shared walls or fences. A servitude could also make a single owner entirely liable for the costs of upkeep. If one neighbour refuses to make essential repairs, anyone who is entitled to enforce the servitude may obtain an estimate of the costs of repairs, though it is unlikely that a contractor will undertake to handle the repairs if the person responsible for payment refuses to do so.

The owner of a wall who is not bound by a servitude is usually under no obligation to carry out repairs. However, in the case of deterioration that is likely to prove dangerous to the public, a local authority might order the owner(s) of the property to carry out repairs. Should no servitude exist, repairs must be carried out by agreement between the two owners.

In both the High Court judgments of Van Bergen v Van Niekerk & Another and Passano v Leissler, the court reiterated the same stance in accordance with the principles laid down in Voet’s Commentarius ad Pandectas.

The respective courts held that in case of doubt, a wall intermediate between two adjoining properties is presumed to have been built on the common boundary. Such a party wall belongs to both the owners of the adjoining properties, irrespective of who built it. Although this is not co-ownership in the accepted sense of the term, the owners of neighbouring properties do have rights against each other.

One view which was taken was that the owners have the rights of co-owners in the sense that each is entitled to the maintenance of the wall encroaching on his neighbour’s property, as well as the part standing on his own property. Another view is that while each owner has no right of ownership in the portion of the wall standing on his neighbour’s ground, each owner is entitled to demand that the other co-owner should keep his half of the wall in a proper state of repair.

The courts seemed to favour the view that each owner owns half of the wall on his side of the median line with reciprocal servitudes of lateral support. Accordingly both neighbours are liable for the cost of the maintenance of the wall and both must refrain from doing anything which may detrimentally affect the stability of the wall.