What is an encroachment?
An encroachment is a part of a building that sits over, on or under someone else’s land. Think of a roof overhang, a bay window or a balcony that crosses the boundary, or a foundation or service pipe running under the neighbouring plot. In construction the same word is also used loosely for a raised structure built over an existing level — a mezzanine, or a storey above a passageway.
Encroachment and boundary law
Encroachment is primarily a legal matter. The starting point everywhere is that you may not build on someone else’s land. Most legal systems then soften that rule for a builder who crossed the boundary in good faith, typically by allowing the structure to remain in exchange for compensation or a registered right, provided the neighbour did not object immediately. The details vary by country, so check the position locally before relying on it.
Practical consequences:
- Measure before you build. The boundary is not necessarily where the fence stands. If in doubt, have the line set out by a licensed surveyor — far cheaper than a dispute afterwards.
- Watch the overhang. A roof overhang or gutter crossing the line is already an encroachment, even if the wall itself stands inside the boundary. When building an extension right up to the line, allow for the gutter width.
- Record any agreement. If a neighbour accepts an encroachment, register it as an easement. A verbal agreement lapses when the neighbouring property is sold.
- Planning permission is a separate matter. A permit says nothing about private property rights. You can hold a valid permission for something that is nevertheless not allowed under boundary law.
Encroachment as a structural issue
Where a building part is carried over a passage, a road or another property, it needs its own load-bearing structure, sufficient clear headroom below, and a fire strategy for the space underneath. Access for future maintenance is worth settling in writing at the same time — you will need to reach the underside of that structure eventually.
Related terms
- Boundary line
- Easement
- Cantilever
- Roof overhang
- Planning permission
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