How to Prepare to Build a Duplex. There are some important differences between regular home construction and building a duplex. While maximizing space is one benefit to building this way, it also increases the land development use and shares the cost of construction. Here's how to build a duplex.
Check your local building codes. Each municipality has its own rules as to what property can be used in what fashion. Duplexes are generally considered "Residential 2" which means that they are multi-family structures. Some zoning districts do not allow this type of home to be built.
Acquire a piece of property in a zone that allows multi-family structures to build a duplex. Once you have done your research as to which property can be used in what fashion, narrow your land search.
Consider the infrastructure before you purchase the land. Consider things such as water, sewer, gas and roadway development as well. Make sure you have an initial survey done to see what you are actually purchasing.
Design your duplex or acquire pre-made plans and get the drawings approved by the municipality. Contact your local building code officer for the specific steps your municipality requires for approval.
Contract the work to build the duplex. Your duplex needs large scale plumbing, paving, block, framing, interior and other contractors to get the job done. You may want to be the general building contractor, or you may want to hire a general building contractor.
Survey the property again to set the new property lines between the halves of your duplex. In building a duplex, the second survey is needed to place the property line. This is done after the structure is built to ensure no part of the building was inadvertently built to one side or the other of the property line.