The separation wall between neighbors
(Hadrian's wall as an imposing dividing wall between neighbors -English men and Scots)
Wall and planting between neighbors
1.Our open space is getting smaller, we are living closer together, more and more in apartments, every centimeter is slowly starting to count.
A new neighbor building next to you will want to shield his privacy through fences (which are now becoming more aesthetic).
He will then place his own fence on his property (so not on the boundary line) in order to be able to choose the type of fence himself (unabridged possible rules for a subdivision permit or an environmental permit, otherwise the wall must generally be 2m60 high and in cities with more than 50,000 inhabitants even 3m20.[1]
2. Normally, the new neighbor will contact you and talk to you about the placing of the fence.
If he does not do this and therefore wishes to use the fence as common, you can request him to stop and, if necessary, even have his work stopped by means of a preliminary conjunction procedure.[2]
Admittedly, this does not prevent you from asking your neighbor that your existing fence on the boundary line be made common (he must then pay half of its value and of the land).
If there was a very narrow strip between the boundary of the lot and this fence, and you wish to make it common, your neighbor could even be forced to sell this piece of land.[3]
Conversely, if your neighbor installs constructions on your wall or uses the foundation of the existing wall, this can lead to a forced purchase (by your neighbor).
However, this does not suffice when, for example, installing insulating material or installing slabs or coverstones to prevent moisture seeping in.
3. When buying an apartment in a city, the buyer could be faced with a wall commonality caveat clause. This then provides the property promoter with the option to have this neighbor pay for the construction of an adjacent building. Normally this must be settled with the purchase price, but this can be checked.
4. Plants can also be a source of great irritation.
Hence, for tall trees or trees that are naturally considered to be tall trees, a minimum distance to the border of 2 m is required, and for the low-stemmed trees 50 cm.
Trees that are espalier (ie guided in one direction) may be placed closer and are the exception.
You can cut the roots of neighboring trees yourself (after informing your neighbor in writing and waiting 60 days).
You cannot do this with overhanging branches but you can always request that they be pruned.
You can only assert a right to the abandonment of plants for a period of 30 years, after which the limitation period has expired.
If a judgment has been intervened whereby your neighbor has to grub a tree (for the nuisance he causes with it or for not respecting the distance), the administrative authority must generally also respect this decision. However, all this is certainly not yet streamlined, so that the practice with a difficult neighbor can still cause problem
[1] Article 663 C.C.
[2] T.B.O. 2018, Johan Van De Voorde, The Common Wall and the Distance from Planting and Fences to the Border Line, pg. 169 with references
[3]