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Missing middle · The supply strategy

The cheapest
housing we can
build is the
hardest to build.

Townhomes, duplexes, triplexes, fourplexes and condominiums. Marion County has 264,000 single-family houses and 9,356 duplex parcels. If we want more homes and lower prices, this is the fastest and least expensive place to get them.

2.1% Share of Marion County's housing that is a duplex. Detached single-family houses are 59 percent. Census American Community Survey, 2020 to 2024.

What the middle is

Between a detached house on its own lot and a large apartment building sits everything most American neighborhoods were built out of before 1940, and almost nothing built since.

Townhome

1 unit, attached. Shares side walls, owns its own lot and front door. The cheapest form of ownership housing there is.

Duplex

2 units. Two homes, one building. An owner can live in one side and rent the other, which is how a first house gets paid for.

Triplex and fourplex

3 or 4 units. Reads as a large house from the street. Four families on the land that holds one.

Courtyard building

5 to 9 units. Two or three storeys around a shared yard. Still wood frame, still no elevator, still walk-up.

Condominium

Owned, not rented. The same buildings, sold by the unit instead of rented. The only way most of this becomes ownership housing.

What these share is why they are cheap. Wood frame instead of steel and concrete. Walk-up instead of an elevator. Surface parking or a driveway instead of a structured garage. Built by small local builders on single lots, not by national capital on assembled land. A fourplex costs a fraction per home of what a mid-rise costs, and it can go up on a vacant lot that already has water, sewer and a street in front of it.

They also fit where we need them. A Reinvestment on the east side is full of 30 and 40 foot platted lots with the infrastructure already paid for. That lot will never hold an apartment building. It will hold a duplex.

What we have,
and what we stopped building

Marion County has 441,040 housing units. The middle is 16 percent of them, and most of that is old.

One unit, detached
261,039
One unit, attached
34,107
Two units
9,207
Three or four units
29,250
Five to nine units
35,121
Ten or more units
65,183
Mobile home
6,825

Gold bars are the missing middle. Census , 2020 to 2024, table B25024. Bar length is relative to detached single-family.

's records tell the same story from the ownership side. Marion County has 264,216 single-family residential parcels and 19,207 condominium parcels, against 9,356 two-family parcels and 316 three-family parcels. Three hundred sixteen. In a county of nearly a million people.

The point of those numbers

This is not a market preference. Duplexes and fourplexes were normal here, and then the zoning code made them illegal or discretionary on most residential land, and we built almost none for two generations. The stock we have is largely pre-war. When people say the market does not want this product, what they mean is the market has not been allowed to try.

Abatement by right,
aimed at the middle

These are one strategy, not two. A published earned is what makes a small building pencil, and the middle is where a published abatement does the most good per dollar.

The schedule

100% for ten years

An two-to-four unit building gets the full abatement on the value it creates, in any zone, including zones where a detached house would get 75 percent or nothing at all.

Why owner occupancy

The rent pays the mortgage

A household that could not carry a $400,000 house can carry a $400,000 duplex, because the other unit pays a share of it. This is the oldest wealth-building machine in American cities and we zoned it out.

Why by right

Small builders cannot wait

A national homebuilder can absorb a year of hearings. The person building one fourplex cannot. Certainty is worth more to them than the money, and it costs the city nothing to give.

What it produces

Rental without a landlord from out of state

Every owner-occupied fourplex is three rental homes whose owner lives on site. Compare that to the accountability problem on the accountability page.

Cincinnati already gives extra abated value to two-to-four unit projects, so there is precedent for writing it exactly this way. And the money lands harder here than on a house: because rental property is capped at 2 percent of value instead of 1 percent, an abatement on a fourplex delivers about 72 percent of its face value against 38 percent on a homestead. That is roughly $83,000 over ten years on a $520,000 fourplex, and $3,526 per home per year on an apartment building. The arithmetic is on the abatement page.

What actually
blocks it

Money is rarely the first obstacle. Four other things kill these buildings before a lender is ever called.

The zoning code

Most residential land in Marion County allows one dwelling per lot. A duplex needs a or a variance, which means a hearing, a lawyer, notice to neighbors and months of calendar. The 2026 state housing law requires the city to review the code against exactly this list of barriers by January 1, 2027.

FixMake two-to-four unit buildings a permitted use on residential lots that meet objective standards, in the code review the state already requires. That is a text amendment, and under current law only the can start one. That is its own problem.

Lot size, setbacks and parking

Even where the use is allowed, a minimum lot size written for a ranch house, a required side yard on both sides, and two parking spaces per unit can make a fourplex physically impossible on a 40-foot lot. The rules do not ban the building; the arithmetic does.

FixObjective form standards for small buildings: height, setback, entry placement, and no parking minimum where transit or an alley exists. The state's review list names parking, lot size, setbacks, roof pitch and garages specifically.

Nobody has drawn the plans

A small builder pays an architect for a custom design on every project, which can be $20,000 to $40,000 spread across four units. Cities that publish permit-ready plans remove that cost entirely. South Bend gives its infill plans away and claims hundreds of thousands in design savings; Bryan, Texas reports more than $8,000 per unit.

FixFinish and publish the pre-reviewed housing plans the put out for bid in early 2026, and pair each plan with by-right permitting and the abatement schedule.

Condominiums are hard to finance and to insure

Selling the units instead of renting them is what turns this into ownership housing, but small condominium projects carry construction-defect exposure, association requirements and lender rules that many builders will not touch. Much of what does get built ends up rental by default.

FixThis one I do not have solved. It is partly state law and partly the insurance market. I want to hear from builders and lenders on what would actually change the answer, and I have flagged it as open rather than pretending otherwise.

What this
would add up to

The honest version, without a projection I cannot defend.

Marion County permitted 1,342 housing units in 2025. The region needs roughly 8,400 a year by the regional planning organization's 2024 estimate. Nobody is closing that gap with fourplexes alone, and I am not going to claim they will.

What I will claim is the arithmetic of where the next thousand homes are cheapest. There are more than 19,000 vacant platted residential lots in this county, most of them in neighborhoods where the streets and sewers already exist and a detached house will not pencil. Putting two to four homes on a lot instead of one, with a published abatement and a permit-ready plan, is the lowest-cost new supply available to us. It needs no land assembly, no structured parking, no state money, and no new department.

What I would need before claiming a number

A count of how many of those vacant lots actually meet lot-width and frontage standards for a two-to-four unit building, and what a duplex costs per square foot here against a detached house. The first is a mapping exercise on data the city already holds. The second should come from builders, not from me.

What this means for you

Pick who you are in the bar at the top and this section changes.

If you build homes

The three questions I need answered: what does a fourplex cost per unit here against a detached house, what lot width do you actually need, and would a published plan set plus by-right permitting get you to build one this year. If the answer is that condo exposure makes ownership impossible, say that too.

If you sell homes

Appraisals are the quiet killer here. If there are no recent sales of small multifamily in a neighborhood, the appraisal comes in low and the loan fails. Tell me how bad the comparable-sales problem is in the Reinvestment tracts, because if it is the binding constraint then the abatement is not the first fix.

If you design homes

The pre-reviewed plan sets are the single highest-leverage thing on this page. A fourplex that fits a 40-foot platted lot, meets the code without a variance, and can be financed by a household at is the drawing the whole strategy waits on.

If you finance homes

Owner-occupied two-to-four unit is a conventional product with well-understood , and rental income counts. What I want to know is where it breaks locally: appraisal comparables, construction lending for a builder doing one building, or condominium project approval.

If you run a housing nonprofit

A fourplex where the owner lives in one unit produces three rentals with an on-site owner, at a cost per home well below new construction elsewhere. If your model can hold the land or the ground lease under that, the combination reaches deeper than either tool alone.

If you live here

This is not about towers. It is about buildings that look like large houses and were normal on Indianapolis streets a century ago. If there is a vacant lot on your block, the realistic choice is a duplex or nothing, not a duplex or a single-family house.

If you make policy

The code review the state requires by January 1, 2027 is the opening. Two-to-four unit by right with objective standards, no parking minimum near transit, and the abatement schedule attached is one coherent package, and the hearing to do it is already on our calendar by law.