Changing a Duplex to a Triplex with the City of Seattle

Changing a Duplex to a Triplex with the City of Seattle

Rental Property Investor · Seattle, WA · Member since 2017 · 13 posts · 4 votes

Hi All, 

I have been looking at a Triplex in Seattle very close to where I currently live that would allow the potential to house hack.  It is listed as a Triplex, however might be considered as a Duplex by the City of Seattle. Does anyone have experience changing a Duplex into a Triplex with the City? Is it a difficult process? Should I even bother?

I have inquired with the listing realtor about the property and here are the details: 

• We believe the property has been used as a 3-unit building since roughly 1953 (prior to the City of Seattle annexing the area).

• Unfortunately, it was not continuously used as a triplex (the triplex use was apparently interrupted in 1971), so it was established that it would not be grandfathered in and no longer be considered a legal triplex by the city (even though the County records designate it a triplex).

• Property records obtained from the City of Seattle Permit Center are available upon request

• It is currently considered a legal duplex by the city.

• After meeting with the City of Seattle Permit Center, it was found that there is a path to getting three rentable units without an owner occupancy requirement:

• The owner would need to file a building permit for a change of use.

In order qualify, the owner would have to do the following:

• Change the use to a SINGLE-FAMILY home with two accessory dwelling units ("ADU"). Duplexes are not allowed to have ADU's.

• Because of the age of the house, there are no restrictions to how large the ADU units can be. The current configuration of two units that are roughly the same size, and one smaller unit, is apparently OK.

• One of the ADU units must either be built to a high environmental standard OR must be reserved for low-income housing. The property would need to show that the units meet safety standards (ingress/egress, etc.), but we understand the paperwork is otherwise fairly simple.

▪ The review time is about 2-3 months once the application is submitted.

Any feedback or input is appreciated. 

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  • Architect · Providence, RI · Member since 2016 · 258 posts · 195 votes
    6y

    Sounds like you have your answer! I have a buddy (architect) who does this stuff in Seattle, let me know if you need a recommendation. 

  • Member since 2019 · 4 posts · 5 votes
    6y

    It sounds like the same answer i recently received. I have a duplex in Seattle that I'm looking at adding a DADU to, and in order to add that third unit I need to reclassify the home as a single family residence with an ADU first. Then I can get the permit for the DADU approved. Seems backward to change a home to a SFR in order to get 3 units, but that is the way it is. Good luck if you move forward with it!

  • Rental Property Investor · Seattle, WA · Member since 2017 · 13 posts · 4 votes
    6y

    @Christian Nossum I agree, the process seems backwards! I just inquired with the permits office today for alternative options.  I will let you know if I find out anything else.

  • Seattle, WA · Member since 2017 · 275 posts · 223 votes
    6y

    My triplex (built as, but was in an area downzoned in the 80's to SFR) was grandfathered, but showed on county records and building permits as a triplex. Also has 3 electric meters. I was advised at the time that this was sufficient that if anybody ever complained about its being used as such (triplex rental property) this would be enough that any court would sustain the current use regardless of zoning or if it had been continuously occupied or not.

    If the property has 3 electric meters or other improvements that likely had permits in order to be converted for use as a triplex, then regardless of whether it had continued occupancy or not it might be OK.

    That said,  I am no land use attorney and you should probably ignore me and talk to one of them.

    I guess the other question is what constitutes 'high environmental standard' - high efficiency heating, plumbing and electrical is comparatively easy in many cases.   Upgrading walls and ceilings on an existing structure to be thick enough for R-<bignumber> could cause a lot of problems with existing layout. 

  • Rental Property Investor · Seattle, WA · Member since 2017 · 13 posts · 4 votes
    6y

    @Brian Hughes Thanks for the input.  I am looking for an alternate solution to hopefully stay away from having to make those high environmental standard improvements or keep one of the units reserved for section 8. I will double check to make sure the property has 3 separate electric meters.  

  • Architect · Seattle, WA · Member since 2017 · 160 posts · 81 votes
    6y

    @Devin Chong I'm an Architect in Seattle, just saw this thread and thought I would reach out. Feel free to DM me if you have any other questions or want an Architect / investor to put a set of eyes on something.

    Best,

  • Asheville, NC · Member since 2017 · 385 posts · 274 votes
    6y

    This may not work given the circumstances you described but I would ask the city zoning board if the property could be designated as a "nonconforming legal triplex" . That is what I had to do when I bought my duplex. It had two meters and the units were separate. I wrote that contingency into my purchase offer. Does the property have 3 meters and are the units completely separate? Mine was considered a SFH for some reason.

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