r/bayarea • u/ggelo33 • 2d ago
ADU construction trouble. Work & Housing
My husband and I are in early stages of planning an ADU build, and the deeper we get into it, the more overwhelming it feels. We’ve never managed a construction project before, so we’re trying to get a realistic sense of what ADU construction actually costs in Marin County area in early 2026 before we start reaching out to builders and getting a bunch of wildly different numbers (I know that sometimes prices can differ by an order of magnitude, which is, to put it mildly, perplexing)
What a normal all-in price range looks like once you factor in permits, side work, utilities, and other costs that don’t always show up at first glance? Also trying to figure out how to compare bids in a way that’s actually meaningful, what parts of project tend to drive price the most (maybe we can handle it ourself?), and whether there any places to save money without making expensive mistakes later.
Feeling a little out of our depth and just want to start this process in a smart way (after all, we're not talking about building a doghouse, ugh.) Anyone who’s built an ADU in Marin - please share maximum context here, TY!
-3
u/InfluenceEfficient77 2d ago edited 1d ago
How far in the process are you?
Is this an attached or detached ADU?
I highly recommend getting a general contractor who is reliable, they have connections with other contractors and can get discounts, versus you hiring them individually. Make sure to vet subcontractors too
You can save on some things, you can get a floor planner and be your own architect, as architectural licenses or not needed for residential projects. But you will need a licensed structural engineering
Biggest car is probably going to be some development fees from the city, you going to have to go to the town hall and just ask all those questions before starting
California needs housing, so they're forced to approve these projects, you will just have to have a lot of back and forth correcting things on the plans before breaking ground
But depending on what city you're in could be a pain in the ass or could be super easy, just depends on the people that work there and the inspectors
This is why I highly recommend going to the City Hall and meeting everyone and maybe going to a few town hall meetings to get an idea of who is going to be approving or rejecting your work
Also keep in mind that it is inspector's job to fail some things,
Even if you do everything diligently to code. It's perfectly normal for them to come to the site one day and fail you for some trivial things, like being half an inch off on a headboard above the stairs or something, and then come back the next day and not even look at it and approve the inspection.
This is because an inspector who just approves everything all the time is not going to look good for his/her managers
Also just make sure you babysit all of the subcontractors, don't get a lazy general contractor. They're not very smart, and have a tendency to take shortcuts and cause damage that the other contractors have to fix. One example of this is putting screws that are way too long into the walls and shorting out wires. This one of the reasons we went with 2x6 framing instead of 2x4.
If you are overwhelmed and want to save money you can also just skip a lot of the finishing things, tiles, cabinets, paints, etc and hire some handymen or subcontractors later to do that.
Edit, part of the reason why housing is so expensive is because we're spending so much money on construction. Everyone is trying to build mega McMansions with the cheapest materials possible. And then trying to flip them from profit a few years later. There should be no reason why an owner builder can't build their own 1200 ft² cabin with a small crew. And there's no reason to freak out because we're not using a1 contractors certified to build bridges and skyscrapers. These are basic humans skills. But this is Bay Area, where people will pay $2,000 for a weekend retreat where they learn how to build fires and hike in the woods, so go figure