When one boundary wall of a structure is built right on the property line, it is said to have a zero lot line. This technique is used in both residential and commercial construction for a variety of reasons, with homes which are laid out in this way being referred to as “zero lot line homes.” In some regions, building codes may actually prevent people from building a structure which has this type of line, while in other areas, this type of construction may be permitted. Many housing developments and subdivisions apply for waivers of setback rules, if they exist, so that zero lot line homes can be built.
One of the main reasons to build right along the property line is to create more usable space on the lot, especially if the lot is small. A home with setbacks will be surrounded by several small patches of lawn or garden which may require a lot of work for minimal returns. By contrast, a home built right along the property line can have one large outdoor area, which is why such structures are sometimes called garden, patio, or narrow-lot homes.
Building along the property line can also be used to maximize indoor space by building a larger structure, or to eliminate the need for landscaping altogether by filling the lot, as is done with some retail businesses and town homes. A store, for example, might butt up against the sidewalk with walls which are very close to the property line, and a small space in back for parking.
Promoting zero lot line development can encourage people to use available land more efficiently, and it can sometimes be used to create more environmentally friendly designs by encouraging people to pool open space together to create park-like areas which create habitats. For example, homes in a housing development might cluster around a central common area, rather than each having a small yard. People can sometimes enjoy more privacy as well by pushing a home up against one of the property lines.
There are some distinct disadvantages to zero lot line construction. One of the big issues is that it is often not possible to include windows, as another structure may be right on the other side of the property line, and sometimes structures even share a wall in a zero lot line development. The lack of space can also become an issue during disputes over noise and land use, because there is no buffer between neighbors. Maintaining the exterior of the structure can also be challenging, as any sort of cleaning, maintenance, and construction will encroach on the neighboring property or public land.