Attached ADU in Fremont (with Garage + family room)

Hello people,

[I am new to this forum and my first post]

We bought a single family home in Fremont with a side loaded garage (24 ft x 20ft) and the back of the garage is a family room (15 ft x 15ft) which we rarely use. I was doing some online research about ADUs and trying to find info to understand the pros and cons with addition of an ADU.

The document ( mentioned that in case, existing garage is converted to an ADU, the parking spaces lost as a result of conversion can be shown in different parts of the property, even in the setbacks. We have 20 feet setback between our side load garage and adjacent property of which, I am thinking of using 15ft for a single car garage (still need to check whether city allows it). So, before conversion, we had 2 in-garage + 4 on-street + 2 off-street parking spaces and after conversion, will be 1 in-garage + 4 on-street + 3 off-street parking spaces .

I am trying to understand the changes in property value with this new addition.
We will be adding around 650 sq ft of living space to the property but from a double car garage to a possibly single car garage. Can someone help us understand the issues/affects on property value or any other issues in general with ADUs ?

(This property is on a corner lot and is 100 ft wide. We have enough space on street for curb parking)

Thank you in advance for help.

Many people may not prefer buying a home without garage whether they use it or not. Garage space is usable space, but not included in sqft of the home. IMO, Value wise, it degrades.

I do not have any good experience in such conversion. City is tough on setbacks, won’t relax from standards.

Regarding conversion, you can do with city permit or without city permit (Risky as you are aware), but I do not prefer garage conversion into dwelling area.

Long back, I purchased garage modified for dwelling and converted back to original (the garage).

Thank you for the reply Jil.
We will not go for ADU if we can’t add a single car garage. Assuming, we added a single car garage in place of two car garage, can you please let us know any other issues with conversion.

All I know the wall in garage is not built for dwelling purpose, noise, heat, cold may be there. I do not think this will be suitable for old people during winter and hot summer.

The garage standards are different from in-house standards.

On any case, city setback compliance you need to look at it. If you have large lot, you can better extend the home nicely than garage conversion.

I do not have any experience, but there are few well experienced will soon give you idea.

ADUs add little value. Appraisers are gun shy and a lot of buyers don’t want strangers on their property. But they can pay for themselves in cash flow fairly quickly. Example… I had a ADU on my property in RWC. 650 SF one bedroom pool house. Legal second unit with is own address. Appraisal and cost was $75k. Rent was $2500. Paid for itself in less than three years. Added little value on sale, except that the buyer wanted it for their maid.

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:astonished: How big was the house?

4000sf. The house has to be much bigger than an ADU in San Mateo county. But if the house and ADU are similar in size you have a duplex. Definitely worth less than a comparable sfh.


Even though the government says that 150,000 ADUs could be built in the BA, very few have been built. Less the 70 in 4 years in SF. The cities make it too difficult. Have too many rules. And how many people want strangers living in their back yards?. Don’t plan on appreciation just cash flow. And be prepared for conflicts and neighborhood opposition. Parking and noise two big concerns.

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Thank you Elt1.
Our home is 1644 sqft and planned an ADU of size 600 sqft.
Looks like the pros and cons are not as straight as I thought. Might depend on too many parameters.
We will try to investigate further. We will try to go for an ADU only if we are permitted to build a single car garage in existing setbacks. Spoke to one of the contractors and looks like they will let us in this case. Will update once I investigate further.

They specialize in adu s

(Not an endorsement or referral)

All depends on the cost of the remodel. At $75k it will pay for itself in 3 years. $150k 6 years… Don’t count on appreciation. Look at other investments for better returns to complete your analysis. I am currently remodeling a 3/1 1300 SF house. Gut to the studs complete job $150k. Double what it would have cost 10 years ago.

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Suresh I am trying to build ADU as well in Fremont. I have a corner lot and I was told city has restrictions on corner lot for ADU. Wondering if you have information on restrictions?

I dont know of any such restrictions for corner lots. Though the counties in CA passed this law, there is not enough support from the government agencies. It is a very hectic process if we need to do it on our own. All this is possibly because of lobbying by real-estate companies.

Have you done your ADU project?