The real cost of building an ADU will depend on the type of ADU , usually most people assume a pre manufactured ADU will be less costly but that is not always the case . Pre manufactured ADU's only include the material shipped to the site and may not include the labor , and pre construction costs , plans , permits, engineering , foundation, utility connections and interior finish. These items can add up to a substantial amount of your construction cost . A custom ADU should include all these items but will cost a little more because of the custom design and construction involved . ADU4U2 includes some of the pre construction cost as an option but includes all the building costs required . The larger your ADU the lower cost per sqft normally . Cost per square foot runs in the range from $250 to $350 per sqft .

In the Southern California area your prices may be higher than other parts of the country because of the higher cost of materials and labor and this reflects in the price of homes. You can save some money if you do some finish work yourself such as painting , floor coverings , cabinet installation etc. Most good contractors will be close in price in estimating an ADU , if you get a low bid more than likely that contractor is not as experienced in the construction estimating process and may have underbid the project , this could lead to a poor quality build as he tries to save money to complete your project . Contractors essentially pay the same for materials anywhere so there is no saving for them , and labor cost for good journey man trades people and subcontractors is pretty consistent . There are some areas you can save on such as acrylic shower units vs ceramic tile which is 5 times the cost . Standard assemble cabinets vs pre assembled can save you 30 % of the cost of cabinets . Pre fabricated granite countertops vs custom fabricated counter tops can save you 50 % on countertops. Luxury vinyl laminate vs tile or carpet vs Luxury vinyl laminate can save you 20 % . These are just some of the savings you can plan in building your new ADU ,