Boundary installations, fence and boundary wall: ownership, maintenance and costs

Boundary installations are structures that separate two neighbouring plots from one another. Under the ABGB these include fences, hedges, walls, earth furrows, dividing partitions and similar installations. They stand on the boundary line and serve both neighbours to demarcate their properties.

For such installations section 854 ABGB sets up a presumption. Boundary installations between two neighbouring plots count as joint property of both neighbours, unless marks such as coats of arms, inscriptions or other evidence prove the contrary. The presumption therefore applies whenever nothing points to sole ownership.

It is important that this presumption is rebuttable. Whoever claims that the installation belongs to them alone must prove it, for example by coats of arms, inscriptions or other indications. If the proof fails, the installation remains joint property. A hedge or a fence wholly on one plot, by contrast, does not trigger the presumption at all but is sole property from the outset.

Where a boundary installation is joint property, its use concerns both neighbours. Section 855 ABGB governs for a common wall how far each may use it. Each co-owner may use the common wall on their side up to half its thickness, for example for recesses or cupboards, as long as they do not endanger the wall and do not hinder the neighbour in the use of their side.

From joint ownership it also follows that maintenance and costs concern both sides. A genuinely common installation is, by the logic of co-ownership, to be maintained and borne jointly. A purely own installation on one’s own ground, by contrast, is solely the matter of the respective owner who erected and maintains it.

Before a repair or alteration is due, it is therefore worth looking at the ownership position. If the installation belongs to both, coordination and cost-sharing are required. If it belongs to one alone, that owner bears the costs alone. Where there is a dispute about use or the bearing of costs, a legal assessment clarifies which rule applies in the individual case.

The law knows no general duty to enclose one’s plot. Section 858 ABGB, however, obliges every owner to provide for the necessary separation on the right side of their main entrance. Whoever meets this duty erects the installation there on their own responsibility, in so far as it concerns only them.

On the costs a distinction must be drawn. The costs of a genuinely common installation are, by the logic of joint ownership, to be shared. A purely own installation on one’s own ground, by contrast, is solely the matter of the one who erects it. Whoever puts up a fence only on their own ground therefore bears it alone and cannot readily make the neighbour share the costs.

Where neighbours dispute the course of the boundary itself, section 851 ABGB applies. Where the boundaries have genuinely become unrecognisable or are disputed, they are fixed according to the last peaceful state of possession. Where this too cannot be established, the court allocates the disputed strip by equitable discretion. Each party may additionally pursue a better right in ordinary proceedings. More on trees and hedges at the boundary can be found in our article on trees, roots and branches at the property boundary.

With trees and hedges the position is decisive. A tree or a hedge planted wholly on one plot is the sole property of that owner. The neighbour has no share in it, even if branches or shade reach onto their side. The presumption of sec. 854 ABGB does not apply here, because the installation does not stand on the boundary.

It is different with a hedge or a shrub on the boundary line itself. Where the installation genuinely stands on the boundary, it counts as joint property under sec. 854 ABGB, unless marks prove the contrary. Maintenance and costs then concern both neighbours, as with a common fence or a common wall.

Whoever plants or puts up a fence should therefore consider the position relative to the boundary. An installation just on one’s own side remains sole property, an installation on the boundary becomes common. This small difference decides who later maintains and pays. A legal assessment helps to judge the position correctly.

First settle the position: does the installation stand on the boundary or wholly on one plot? Secure photographs, old plans and any survey documents. Look out for marks such as coats of arms or inscriptions that could point to sole ownership. This clarification is the basis of every further assessment.

Seek a conversation with the neighbour and put any agreement about repair and costs in writing. With joint ownership coordination and cost-sharing are required. With a sole installation the owner bears the costs alone. If no agreement is reached, examine which legal path works.

If the boundary itself is disputed or the other side does not respond, early legal advice is sensible. A legal assessment clarifies whether the issue concerns ownership, maintenance, costs or the course of the boundary. An overview is provided on our focus page on construction damages and liability.