Housing, Policy Analysis

Attainable Housing Part 2: ADUs

This piece is part two of a series on workable policy solutions to address the shortage of attainable housing in Kirkwood. Part one, on reforming our minimum lot size regulations, can be found here.


I’ve been working on Accessory Dwelling Unit (ADU) policy a lot for my day job recently and the more I’ve delved into it, the more I’ve thought about its potential in Kirkwood. Kirkwood actually already has ADU legislation. Back in 2021, Kirkwood passed zoning changes that legalized ADUs for the first time.

But ADU legislation is really hard to get right. California, faced with an attainable housing crisis of its own, legalized ADUs statewide in 2016 but saw almost no units come online due to the hydra-like nature of land use regulations. You cut off one head of the snake (legalize ADUs) and five more show up.

Kirkwood has faced similar challenges in getting our ADU regs right. Overly wrought stipulations that I warned would likely ensure relatively few ADUs were built, have achieved just that. In fact, if anything I underestimated their impact. According to Kirkwood’s planning department, no additional ADUs have been permitted since the legislation was enacted.

But California’s example also presents a vision for how to move forward. California has revised their initial 2016 ADU legislation more than six times in the intervening years to address flaws in the original bill. With each revision, the process of building ADUs has grown easier and production has grown proportionally. I think that’s what we’re going to have to do in Kirkwood too. It’s really good Kirkwood has some ADU legislation on the books; that gives us something to tweak. Now it’s just time to actually tweak it.

So what I want to do is go through the five relevant sections of the existing ADU legislation and see where exactly we need to make adjustments. Let’s start where we last left off: Those pesky minimum lot sizes.

1. Minimum Lot Size

(8) There shall be a minimum lot area of 15,000 square feet for any lot that contains an accessory dwelling unit.

As we talked about last week, Kirkwood has four different Minimum Lot Sizes depending on what variety of single-family zone you fall into. 15,000 sq ft is the second smallest MLS, so this requirement excludes all the R-4 Single Family zone (7,500 sq ft). That’s unfortunate, because R-4 zoning not only comprises a large chunk of Kirkwood, but it also comprises some of our most walkable and amenity-rich neighborhoods. We should change that.

Kirkwood zoning map showing where ADUs are currently legal
The flesh colored portions of the map are currently excluded from ADU construction

Even more, the R-4 exclusion ensures that the places in Kirkwood with the single easiest use cases, detached garages with alley access like those on Heege pictured below, are all ineligible as they each fall within the R-4 zone. More on this in a second.

The alley-facing garages on Heege Ave presented here offer a perfect opportunity for ADUs

So I think all Kirkwood single-family lots should be eligible for ADUs, including R-4. Now because the minimum lot size reforms I suggested last week applied to everything besides R-4, the two issues should pair nicely together: R-1, R-2, and R-3 property owners get reduced minimum lot sizes (and the splitting privileges that comes with it) and R-4 owners would get to build the ADUs that are already (ostensibly) legal in the other three single-family zones.

2. Setback Requirements

(4) An accessory dwelling unit that is in a separate, detached building or is added to a detached building shall be constructed in a manner that reflects the architectural style, materials, colors, and roof design of the principal dwelling. Such detached building shall meet the setback requirements for principal buildings in the applicable zoning district.

The first portion of this regulation is annoying and I think in bad taste, but if the community really wants all its buildings to look fake old, so be it. It’s the second sentence that I think is the much bigger problem and what want to focus on.

Because only R-1 through R-3 lots are currently eligible, ADUs currently have to be at least 35 feet from the rear property line. If you have an alley, half of its width can be counted towards that distance.

This is a recurring issue with the ADU legislation that was passed: converting any existing structure into an ADU annuls the grandfathered-in status of that structure. So if you have a detached garage that sits on your property line, converting that garage into an ADU would bring it out of compliance of the setback requirement even though nothing about the exterior of the building changed. Instead, you’d have to tear down the garage, move it however far back it needs to be, and build it from the ground up.

Obviously no one is going to do that, so that means that we’re basically banning ADUs from the places where they’d most naturally fit and be the cheapest to construct. If you’re building a new ADU from the ground up, sure, we can require that it comply with the setback rules (even though the existence of the setbacks themselves aren’t ideal), but if a building is already there, it should keep its legal status. After all, nothing is changing! This feels like the lowest hanging fruit for reform.

3. Maximum Size Restrictions

(9) The maximum size of an accessory dwelling unit shall be 750 square feet of floor area and shall not contain more than two bedrooms. The calculation of floor area shall include basements but shall not include garage space when said accessory dwelling unit is part of a detached garage.

In California, communities are barred from setting maximum unit size requirements smaller than 850 square feet. If ADUs have more than one bedroom, that allowed maximum size gets bumped up to 1,000 sq ft. If California has identified small maximum sizes as a hurdle to ADU production, we should heed the warning and bring our regulations in line with theirs, but this one feels like a little bit smaller potatoes compared to the other changes I’d like to see.

4. Parking Requirements

(10) One off-street parking space shall be provided in addition to any spaces required in § 25-65. Such parking space shall have direct, drivable access to a street.

If I do a “Part 3” on workable attainable housing reforms, it’ll be on parking minimums. Parking requirements giving up on the basic conceit that you can add housing without adding a proportional amount of traffic —which is an argument you have to win if youre going to convince a community to build more housing.

Instituting minimum parking requirements for ADUs in particular is doubly annoying since residents of ADUs have a lower propensity to drive than the average person. This is thanks to ADUs’s popularity with the elderly and those who can’t quite live completely independently due to physical or mental disabilities. Both of these populations drive in much lower numbers, but even if you’re building an ADU specifically for grandma who can’t live alone anymore and doesn’t drive, the city is still going to make you add a parking spot.

Requiring additional parking spaces in situations like these increases both the land required to build an ADU and their associated cost of construction which further discourages their production. Let people add a parking space when they build an ADU if they want to, but don’t require it. On to owner occupancy.

5. Owner Occupancy Requirements

(11) The owner of the lot shall reside in either the principal dwelling or accessory dwelling unit as long as both dwelling units are occupied as residences.

The most restrictive of ADU laws often require the owner of the lot to reside in the principal dwelling unit, which we’ve luckily avoided here. Still, we need to take one more step and not require the owner to live in either the primary or the accessory structure. I admit this sounds like a strange suggestion. From an optics standpoint, you’d probably prefer a dynamic where local residents are building ADUs for their elderly mother to live in rather than some guy who lives in Florida renting out both the primary house and the accessory one.

But California has shown us that owner occupancy requirements in practice have few benefits but potentially large costs. California has banned local municipalities from requiring owners occupy either the primary or accessory structure, and yet the vast majority of properties with ADUs still see an owner occupant. Instead, the biggest impact of this regulation is in curtailing the financing ADUs, because ADUs are expensive.

I’m not quite fluent in finance so I’m just going to defer to this really good piece from Seattle that I found on the subject:

Of the 124,000 eligible single-family lots in Seattle, less than 800 have a permitted ADU.  This is in part because of the cost: the average ADU costs roughly $185,000 — enough to require most to take out a loan.  But ADUs do not appraise; there are too few in the market so banks risk not recouping the value of their loan. It’s a Catch-22: to get a loan for an ADU, you must first have the equity you need to construct one or already have built one to appraise.

https://www.fiximpactdev.com/backyard-cottage-adu-owner-occupancy/

Now investors who already have the necessary equity even without the ADU being appraised present an exception to this Catch-22. The problem is, that those investors typically aren’t owner-occupiers so they’re barred from building ADUs in Kirkwood. We should change that.

The idea here is that you let these investors build ADUs, those ADUs get appraised, and then, now that local banks have an idea of the value of an ADU, they can start offering loans to everyday people where the ADU itself counts towards the equity.

Now just 26.4% of Kirkwood’s housing is renter occupied and a lot of that is tied up in multi-family units which are ineligible for ADUs, so I’m not sure how big the universe of non-occupant single-family homeowners investors is here, but all we need are a few. Repeal the owner-occupancy requirements and you open up the financing floodgates.

ADUs: Our Best Shot at Affordability

Building more housing is such a tough issue to deal with at the local level politically because its benefits are dispersed across the entire region while the costs are concentrated on the voters of the municipality enacting the change. Everyone in the St. Louis area benefits a little from Kirkwood being a more accessible place to live, but only Kirkwood voters bear the immediate burden of construction noise and increased traffic in their “backyard,” and they’re the one who get to vote.

ADUs, much like the Minimum Lot Size reforms I suggested last week, present a way to add housing that flips the script on that dynamic. The region benefits from Kirkwood becoming a more affordable place to live and Kirkwood homeowners benefit from renting out their ADUs (or at least owning a piece of property that has increased value from its ADU potential).

Further, ADUs disperse the cost of additional housing widely and thinly within Kirkwood contributing to a “softer density” than other options. Instead of the 200 new cars worth of traffic that an apartment might add on a single street, ADUs might add four or five cars worth of traffic on every street in Kirkwood.

These qualities give ADUs a uniquely viable political coalition and make them, I think, the single most important factor in tackling Kirkwood’s attainable housing problem. We don’t even have to come up with anything brand new, we tweak some very technical language, see if it has an effect, and then come back and tweak some more.

Advocacy requires some realpolitik if it hopes to actually improve people’s lives. These are my attempts at that compromise. If other people don’t like these particular ideas for adding attainable housing, that’s fine. I just encourage them to offer solutions of their own. The option of keeping Kirkwood the same, for better or worse, has been taken off the table. The only question is how we change and whether we are an active participant in that change or we are simply along for the ride. I think we’ll all be happier with the results if it’s the former.

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Mike Burke

You should read this article before praising ADRs in California. This describes an area in my home town of San Diego. I’ve been living in Oakland, MO fir two decades, and I don’t want to see the same difficulties here. “Where the Suburbs End, New Tork
times, 8 October 2021.

Gwyn Wahlmann

California has a problem with over-population. St Louis County does not. From Normandy down to Lemay, there are plenty of areas crying out for re-development. What makes you think Kirkwood should be singled out to increase density, build out beyond our limited street and utility infrastructure, increase impervious surfacing and stormwater run-off, increase noise, traffic and stress and reduce quality of life?

Mike Burke

Gwyn–I’m with you–runoff from infill housing in Kirkwood has become an enormous issue, one I think the city has corrected recently by amending its codes. The recent July-August rainstorms caused flooding in areas where flooding had never occurred before, even here in Oakland, where I live. The more surface area covered by structure, the more runoff and flooding issues have to be addressed. I think that is one of the major reasons Kirkwood restricts ADUs on smaller (7500 sq ft) lots–where will the water go?

The larger point is, as you say, whether or not increasing the density of homes in Kirkwood makes sense, when there is so much of the county that could be redeveloped. St Louis City is slowly creating new housing in old industrial areas–look at the Hill, even, or the Steelcote project off Chouteau.

Gwyn Wahlmann

—as a Sugar Creek resident, I’m acutely aware of Kirkwood stormwater issues, and with climate science warning of “warmer and wetter” for our region with “more frequent and severe storms” I see Kirkwood’s building, impervious surfacing, stormwater run-off and tree ordinances already inadequate in preventing private property damage. It truly is, “Flood thy neighbor.”

— I agree about County redevelopment. Doubling down on Kirkwood shifts dollars from county municipalities acutely in need while reducing Kirkwood quality of life with unnecessary density.

Look at the horrible photo shown as Gadfly’s example. Too much impervious surfacing, too few trees. How could anyone see that example as an improvement in Kirkwood?

—Kirkwood has no links to Metrolink or any plans to link in the future. It’s illogical to intensify density and worsen traffic problems in a land-locked small town streetscape when areas surrounding the Metrolink network cry out for redevelopment.

Linda Fenton

I’m with Mike and Gwyn. I don’t live in New York City or Oakland, CA for a reason. Diversity, choice in what quality of life means to each of us is important to retain. Not to mention that if climate change isn’t addressed, none of this will matter anyway.

Mike Burke

Parker–I think you’re creating a bit of a false dilemma here–the folks who would want to live in Kirkwood are not likely going to consider the alternative to be Hazelwood. Webster Groves, Des Peres, Town and Country–and of course places out in St Charles County–are more likely competitors. Even with (some number of) ADUs, Kirkwood will remain relatively expensive.

And Kirkwood folks pay more in school taxes than almost any other district in St Louis County–I think Lindbergh schools get very similar average results in terms of college placement and ACT scores on about 2/3 the school taxes. It used to be that Kirkwood and Webster Groves were almost interchangeable in terms of demographics, taxes, and home prices, but Kirkwood home prices have risen since 2008 market crash while WG’s have gone down somewhat in relative terms. I think the perceived quality of the school system has something to do with that. As for people who live in Kirkwood and who work there as well, I wonder just how many 63122 residents actually work in that ZIP code. I wonder how we could find that out. I think I’m the only one of my neighbors who worked in this ZIP code (I taught at STLCC-Meramec for 20 years)–the others have businesses or practices or other jobs outside of this area.

I understand there’s less concern over flooding in downtown Kirkwood than in other parts of the city, but the runoff issues on streets adjacent to downtown are quite real. Look at streets like Harrison with lots of infills after a rainstorm. I don’t think any of this is unsolvabale, but I also think it’s not as simple as it might seem.

Gwyn Wahlmann

Parker Pence says:
“Us shutting ourselves off to people isn’t going to redirect dollars to Normandy, it’s just going to create economic inefficiencies that hurt the whole region.”

Absolutely disagree. A philosophy of centralizing opportunities in an already well-fed community is no way to create, renew, diversify and extend housing and employment opportunities throughout the metropolitan region. It is a flawed concept to pretend all of StLouis County can and should live in Kirkwood.

Gwyn Wahlmann

Rather than encouraging housing, jobs, commerce, etc THROUGHOUT the St Louis County region, you think it should all be jam-packed into a single municipality? That makes no sense. Higher density only destroys Kirkwood while depriving the larger region of much needed renewal. A lose-lose.

Please transpose your concepts onto a larger context. For instance, high-density multi-family housing near Metrolink stations, where it is needed and makes sense. Not some land-locked small town with a constricted street network and already over-burdened infrastructure as it is.

Linda Fenton

Unsolicited advice, commentary, personal opinions, telling a community what they should be doing that you don’t even live in or understand from the distance you are at, is really pretty bodacious and arrogant. No doubt you have been educated on planning matters and I enjoy reading and contemplating diverse opinions like yours. Having lived on the E. Coast NY/NJ area for several years, I understand what shapes your opinions. But I do think you are sorely out of step with the residents & leadership preferences here in Kirkwood. In fact, reading your lengthy lengthy commentary actually solidifies many readers I heard from today on the existing goals and future planning residents have already stated in statistically valid surveys and community forums. Thank you very much for taking the time to share you opinions.

Gwyn Wahlmann

When it comes to a limited resource, supply cannot always meet demand.

Our planet is a closed system, human population growth, land use and consumption can’t increase indefinitely without destroying the source. Well, same with the microcosm of Kirkwood.

Do you know the story of killing the goose that laid the golden eggs? That was about destroying a resource by trying to extract too much from it. What made Kirkwood desirable is being destroyed by excessive demands.

Anonymous

Kirkwood needs cheaper housing for people and thats why i also support the new apartment buildings going in. the new Apartment building called The James is a perfect example of what downtown Kirkwood needs more of. we need more attainable and affordable housing and the removable of parking lots and replacing them with apartments is one way we can do this.