Speed of construction/faster return on investment. Modular construction allows for the building and the site work to be performed simultaneously. According to some materials, this can decrease the overall completion schedule by up to 50%. This also reduces labor, financing and oversight costs. To save even more time and money, the majority of engineering and design areas are a part of the production procedure. Also unique to modular structure is the ability to simultaneously construct a building's floors, walls, ceilings, rafters, and roofs. During site-built construction, walls can't be placed until flooring are set up, and ceilings and rafters can't be added till walls have been erected. On the other hand, with modular structure, walls, flooring, ceilings, and rafters are all built at precisely the same time, and then brought together at precisely the exact same factory to form a building. This procedure can allow modular construction times of half an conventional, stick-built structure.
Improved Air Quality - A lot of the indoor air quality issues identified in new structure result from elevated moisture levels in the framing materials. Because the modular construction is substantially completed in a factory-controlled setting using abrasive materials, the potential for elevated levels of moisture being trapped in the new construction is eliminated.
Ability to service remote locations. Particularly in countries in which prospective markets might be found far from industrial facilities, such as Australia, there may be much higher prices to build a site-built house in a distant area or an area experiencing a construction boom like mining cities. Modular buildings are also beneficial in providing sanitary and medical facilities where space, time, and money are an issue.
Indoor construction. Assembly is independent of weather, which may increase work efficiency and averts damaged building material.
Environmentally friendly construction process. The controlled environment of the mill allows for more accurate construction when allowing the additional stuff to be recycled in-house. 
Modular buildings have been argued to have benefits over traditional buildings, for a variety of factors.
Quality. Combining traditional building techniques, quality manufacturing and third-party agencies that provide random inspections, testing, and certification solutions for quality control, commercial modular structures are built in strict accordance with appropriate local, state, and national regulations and codes. On account of the need to transport modules to the last website, each module must be built to independently withstand travel and setup prerequisites. Thus the closing module-to-module assembly of independently durable elements can yield a last product that is more durable than site-built constructions. Modular buildings frequently use Structural Insulated Panels (SIPs) in construction, which offer a range of advantages over traditional construction materials. SIPs panels are a mild yet lasting combination of board and either closed-cell polyurethane (PU) or expanded polystyrene (EPS) insulating foam. They also offer exceptional damp and cold immunity when compared to timber and other materials, and are immune to both compression decreasing and cold bridging.  Modular units may also be made to fit in with external aesthetics of any existing building and modular units after constructed can be virtually indistinguishable from a site-built structure.
Flexibility. An individual can add to your modular building, such as creating high rises. When the needs alter, modular buildings can be disassembled and the modules emptied or refurbished to their next usage reducing the demand for raw materials and minimizing the total amount of energy expended to create a building to meet the new demand. Essentially, the entire construction can be recycled in some cases.
Modular construction may also give an advantage in similar classes in the International Green Construction Code.
Low waste. With the same programs being constantly built, the producer has records of precisely what amount of materials are necessary for a specified job. With the consistency, builders can design systems that use common lengths of lumber, wallboard, etc., cut things with maximum efficiency, or be able to order exceptional spans in bulk. While waste from a site-built residence may generally fill several large dumpsters, construction of a modular house creates much less waste. As stated by the UK group WRAP, up to a 90% reduction in substances can be achieved via using modular structure.