Modular construction allows for the construction and the site work to be performed simultaneously. According to some materials, this can decrease the total completion schedule by as much as 50%. This reduces labor, financing and oversight expenses. To save even more time and money, the majority of design and engineering disciplines are part of the production process. During site-built construction, walls can't be placed until flooring are in position, and ceilings and rafters can't be added till walls have been erected. On the flip side, with modular structure, walls, floors, ceilings, and rafters are all built at the exact same time, then brought together at precisely the exact same factory to form a construction. This procedure can allow modular construction times of half that of conventional, stick-built construction.
Modular construction can also provide an advantage in similar classes from the International Green Construction Code.
Modular buildings are argued to have benefits over traditional buildings, for many different factors.
Quality. Mixing traditional construction methods, quality manufacturing and third-party agencies who offer random inspections, testing, and certification services for quality management, commercial modular structures are built in strict accordance with appropriate local, state, and national rules and regulations. Due to the requirement to transport modules to the final site, each module must be constructed to independently withstand travel and setup requirements. Thus the closing module-to-module meeting of independently durable components can yield a final product which is more durable than site-built structures. Modular buildings frequently use Structural Insulated Panels (SIPs) in construction, which provide a range of benefits over traditional construction materials. SIPs panels are a mild yet durable mix of panel board and either closed-cell polyurethane (PU) or expanded polystyrene (EPS) insulation. They also offer superior moist and cold resistance when compared to wood and other substances, and are immune to both compression shrinking and cold bridging.  Modular units may also be designed to match in with external aesthetics of any present building and modular units after assembled can be almost indistinguishable from a site-built construction.
Ability to support remote locations. Particularly in countries where prospective markets might be found far from industrial centers, such as Australia, there can be a lot higher costs to build a site-built house in a remote area or a place experiencing a construction boom like mining towns. Modular buildings can also be beneficial in providing medical and sanitary facilities where space, time, and funds are a problem.
Indoor construction. Assembly is different from weather, which may boost work efficiency and averts damaged construction material.
Flexibility. One can continually add to a modular construction, such as creating high rises. When the needs change, modular buildings can be disassembled and the modules relocated or refurbished to their next use reducing the demand for raw materials and minimizing the total amount of energy expended to create a building to meet the new demand. In essence, the entire construction could be recycled in some instances.
Environmentally friendly building process. Modular construction reduces waste and site disturbance compared to site-built structures. The controlled environment of the factory allows for more precise structure when permitting the additional stuff to be recycled in house. 
Improved Air Quality - Many of the indoor air quality issues identified in new construction result from high humidity levels from the farming materials. Since the modular structure is substantially completed in a factory-controlled setting using dry materials, the prospect of high levels of moisture being trapped in the new construction is eliminated.
Low waste. With the same programs being continuously built, the producer has records of precisely what quantity of materials are needed for a specified job. With the consistency, most builders can design systems that use common lengths of timber, wallboard, etc., cut things with maximum efficacy, or have the ability to order exceptional spans in bulk. While squander from a site-built residence may generally fill several large dumpsters, building 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 through the use of modular construction.