Converting duplex to single home or Triplex to duplex

Hey guys. Any reason that you shouldn’t be able to convert a duplex to an SFR by connecting the units (assuming the garages aren’t in between) or a triplex to a duplex or SFR same way?

Example: Two units have same layout and are stacked, so you build a stairwell between the two living rooms converting a set of 2BR, 1BA to 4BR, 2BA.

Assume that I don’t care about merging the utilities. (Also assume that locations of most interest to me are on the Peninsula, especially RWC and San Mateo.)

Don’t you need to pull permits? And change tax record to reflect the change?

Sidebar: I saw multi-fam prices in SF and around softening in the last 12 months or so. Many have undergone some price reductions. It’s a different world from SFH.


I don’t know. I don’t see why other than pulling permits, I should need to do anything. If a family occupies two halfs of a duplex does it matter?

I’m wondering because a realtor told me some cities might not allow it. I figured maybe elt1 or ptiemann might know.

I think SF has restrictions on converting multi-fam like duplexes to SFH. They don’t want to see a reduction of housing units. Other cities may have similar rules.

It’s about property taxes. 2 addresses, two dings. Uncle Sam wants his blood, I mean, his taxes.

Isn’t that considered a commercial property?

It’s a planing change. Could involve zoning change as well. Since RWC has no rent control, it might be doable. You can go talk to the city building or planning department, it’s possible. They could say that there’s a housing shortage and you are reducing housing supply by merging units

But do you bother to go through the trouble? Is a duplex cheaper than a converted SFR?

Assuming work w/o permit, In some cases, if city finds unpermitted work, they may fine you and ask you to remove/change and do not yield at all.

If you do not get permit, it is an issue when you want to sell the home ! All changes are becoming unpermitted or bonus changes and you need to declare this on sale. Depending on situation, lenders may not approve loan application for your perspective buyers and you will land into TFT issues.

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Its ok in SM and RWC…If there is rent control and tenants then it could be an issue, like in SF…I would not recommend it…R2 neighborhoods are less desirable than R1 sfh neighborhoods…So conversion would not be the highest and best use of the property. .Plus what do you do with the extra kitchen and flow issues?

A duplex is cheaper than an SFR. Not sure what you mean by converted.

I still don’t see why it’s a big deal–what’s to stop me from taking up two sides of a duplex after buying it? So I feel like putting a doorway down the middle and suddenly it’s an issue?

Well, we’re only able to afford the R2 neighborhoods now anyways, and I want a duplex anyways, so the zoning is good for me.

Extra kitchen: Turn it into a laundry/utility room (laundry is currently a rented coin-op unit near the carport–give that exclusively to the third unit). One of the places I’m looking at needs remodelling anyways (original 1950s kitchen with original oven). Remodel and return it to a kitchen on the way out. Another place I saw, the kitchens were both renovated with similar cabinets and are adjacent–get rid of extra freestanding fridge and stove, and turn the second one into…something… bills/work area?

Flow isn’t that bad on either one.

It should be fine if you buy a duplex and use it as a
single family. You won’t sue yourself for illegal conversion anyway.

It could be a plus when your kids all grow up and move out. You can live in one and rent another, possibly to one of your grown children

Is a duplex less expensive than a SFR in the same neighborhood? I did not see this pricing in non-rent controlled cities.

Gentrification is easy in RWC and San Mateo. R2 neighborhood can easily become a place full of tech workers. EPA and east Menlo park might be tough to become desirable neighborhood

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I was thinking the exact same thing-especially with the Triplex which has 2BR/2BAths. That could last for a while–even to the kids having kids. It could really give them all a step up if they wanted to stay. Though I’d have to make sure they’re saving for a down payment at the same time.

I’m seeing some duplexes on for $500/sq ft or less in RWC. SFRs seem to be going for around $700-$900 in same neighborhoods. Very odd. Of course ask and sell are two different things, but one of them is still on the market weeks past offer date.

Agreed with RWC and SM. I hear even EPA and EMP are getting better–they’ll be slower, but probably still gentrify.

Forgot to respond to this.

I think if we bought a duplex/triplex, I’d want to keep it for the long-term. I’d also undo all the changes on the way out and return it to duplex/triplex status to get higher rent yields.

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The difference in pricing isn’t odd per se. The closer you get to multifamily the more the yield matters. Pricing on SFH don’t typically follow yield. What you describe makes things seem more rational.

The difference in costs could be a reflection of condition and quality. Also, it’s possible that while they are in the same neighborhood, the specific neighbors are different enough to affect price quite a bit.

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actually, now that I think about it, the extra kitchen means that I can renovate the lower one (which would be kept) and use the upper one for cooking :slight_smile:

If you don’t like duplexes they are actually more affordable. Mortgage is easier to qualify because you can at least count the other unit’s income.

I don’t think the banks count the other unit’s income in mortgage qualification unless you’ve had two years of experience as a landlord per your tax return (which is BS IMO).

You can buy a tenant occupied duplex and then evict one tenant so that you can live in one unit. That way you can use the income from both units to qualify. This could be a good option if you want to move to SF

In RWC, it would be easier. You can buy a tenant occupied duplex with a very modest income. Then give notice to both tenants so that you can occupy both units. This can be a good strategy for income challenged buyer who have 25% down

Banks don’t allow the use of rental income generated from the tenant occupied unit in a duplex if you don’t have experience operating as a landlord, unless the rules have changed since the last time I inquired about this. If this was possible I’d have done this a long time ago.

Our mortgage broker told us that for an owner occupied duplex that is properly zoned, that we’d need 20% down and could count part of the rent (something like 75%) of the other unit towards mortgage. If the unit is zoned for SFR and has an inlaw unit, then we could not count the rental income because of the R1 zoning.