You may be coming to the table with a ballpark idea of what your ADU could cost – we now need to get a closer look at the final costs so your financing can be ready to get your project underway.
In general the smaller the unit the more expensive per square foot it will cost. Kitchens and bathrooms are expensive compared to hallways and bedrooms. There is not much cheap square foot in a small unit – so overall build as big as you can fit and afford.
Maybe you’re hoping to do some of the work yourself and subcontract out the rest to save some money. Perhaps you have heard it will only be $25,000 to fix up the garage…well legal ADUs can cost a great deal more than that, but with today’s rental market and home values it is totally worth every penny.
There are 2 kinds of costs to add up for every construction project.
Soft Costs.
These costs are sometimes overlooked at first. Depending on the size and location of your project be sure to include in your budget:
Design fees (8% – 15% of construction cost)
Consultant Fees (Structural engineering, Energy consultants, Site Survey Fees *
City permit fees – Your city website should list these
Utility Fees – cost for the new meter/hookup fee
School fees (if ADU is over 500sq. ft. is typically 1%)
Insuring your new structure in homeowners insurance
*Your designer will be able to let you know of any extra consultant fees needed before the design can be finalized.
Hard Costs.
These costs cover the construction and all materials used to build your unit:
- Excavation and foundation
- Framing
- Roof
- Flashing and gutters
- Windows, shades, doors
- exterior trim
- Decks
- HVAC
- Plumbing
- Electrical
- Insulation
- Drywall
- Millwork
- Paint
- Tile
- Hardware
- Mirrors
- Fireplace
- Handrails
- Appliances
In southern California, the average cost to build a detached ADU can range between $300 – $400 per square foot for typical finishes. If you are adding high-end finishes to your ADU because of location and use, then the price will be higher.
A 400 sqft 2-car garage conversion could be less as you are using some of the existing structure. However, if plumbing needs moving, the slab needs cutting, adding fireproofing the walls, etc, all these things will push the costs up.
A detached ADU 499 sqft (over 500 sqft you have to pay school fees) could cost approximately $175,000 – 210,000. Depending on the location and finishes this price could also increase.
So considering the type and use of your ADU will help in counting the costs accurately. Maybe you live in an area with highly paid professionals who will expect a clean marble-clad kitchen or perhaps your parent wants cozy wood cabinetry to feel like home. These kinds of finishes can save or cost thousands of dollars.
THINGS TO ASK BEFORE HIRING A CONTRACTOR
Most homeowners will hire a General Contractor to construct their ADU. After your plans are finished get at least 3 bids from a General Contractor preferably before submitting to the city. If the bids come in too high there will be time to make changes before submitting to the city. After working with many over the years, here is a list of things to ask them and consider.
Do they have any ADU experience?
Can they provide references?
Could you see some of their work?
Are they Licensed?
Do they use a crew or sub work out?
So with all this said – if you would like a free consultation to discuss your ADU options – fill out our contact form and we look forward to helping you.
For more information about ADU uses, check out this next article here.
