Building a small, L-shaped ADU?
Hi,
I am toying with the idea of building a small ADU in our back yard. I want to build a 1 bedroom ADU with a kitchen and 3/4 bath, and it has to be L shaped for our lot. I also want a loft above the bathroom/closet area to be additional space for kids to sleep. With all those desires, it's hard to find a prefab that would work - but does anyone know a prefab company that might be able to customize this? Or have a firm they recommend to design/build one? I'm looking for something on a moderate budget. I've seen some designers that build ADUs for an average of $385K that is out of my range...
Nov 23, 2020
Parent Replies
That was my conclusion, too, that prefab wouldn't work. We are building it in the regular way, and it will be in the range you described. We plan to get a loan and do it!
We've been getting bids to build an ADU during the past year. First of all, check the regulations for ADUs for your city so you know what you can and can't do. For example: ADUs must have a full bathroom; you can't do a 3/4 bath. There are strict height and square footage requirements too.
Here is what we found out about pre-fab ADUs: The reason they are cheaper is because one size fits all - economy of scale. What they sell is what you get. Some firms manufacture the pieces and deliver them to your site on a flatbed truck or with a crane. Other firms sell you a "pattern" that you pay someone else to build. They might have network of contractors that they will recommend or you might need to find one yourself. A big expense will be site preparation, which is not included in the price of a pre-fab ADU. Creating a level spot for your ADU could cost a lot of money. Also I found that pre-fab ADU companies seem to come and go. Over the course of a year researching ADU's, I found that websites would suddenly disappear - even the ones I had read about in trustworthy articles and online reviews just a few months earlier. So make sure you are dealing with a firm that has been in business for a while and has good recommendations, and that is experienced building ADUs in the Bay Area.
After we paid an architect and started taking bids from contractors, the biggest shocker for us was the cost of preparing the site. Our backyard is not completely flat, and it's not super easy to access, so it was going to cost a lot of money to excavate it, haul away rock and debris, and put in retaining walls and drainage. The bids we got were in the $500K range for a 500sf ADU because of the site. In the end we decided not to go ahead with it. I would recommend that you talk to an experienced local ADU designer, tell them what your budget is, and see what they recommend.