Denver’s Missing-Middle Plan Is Really a Preservation Bargain

One question I keep coming back to whenever Denver considers a housing change is pretty simple.

What is the city actually trying to make easier?

The obvious answer here is more homes.

Denver’s Unlocking Housing Choices proposal is exploring where small, house-scaled forms such as duplexes, tandem houses, fourplexes, and cottage housing could fit in low- and medium-intensity residential areas.

But after reading the city’s new financial-feasibility study, I think the more interesting answer is preservation.

The first phase would not simply create more housing options. It would also limit the scale of new house-sized buildings, then offer additional housing potential when an owner keeps the existing primary house or includes income-restricted housing.

That turns the usual zoning debate sideways.

Density and preservation are normally treated as opposites. Denver is asking whether one can be used to encourage the other.

The draft first phase has three linked pieces.

First, it would limit the mass and scale of new house-sized forms. That is the part aimed most directly at the very large replacement house.

Second, it would create a retention and infill bonus. An owner who keeps the existing primary structure could gain additional housing potential on the same lot.

Third, it would create an affordability bonus. More housing could be allowed when one or more income-restricted homes are included.

The city says the approach would be context-sensitive rather than identical on every block. The feasibility study says the proposed changes could touch at least part of 68 of Denver’s 78 neighborhoods, but in some neighborhoods that may mean only several blocks.

Denver’s expected-outcomes analysis looked at 3,559 single-unit homes redeveloped between January 2010 and April 2025.

About 65 percent were replaced by another detached house. About 35 percent became missing-middle housing.

Translated into an average year, that is roughly 237 redeveloped properties: 155 replaced by one new detached house and 82 replaced by missing-middle housing.

Where missing-middle housing was already allowed by right, the result was very different. Eighty-seven percent of the redeveloped properties became missing-middle housing, while 13 percent became a new detached house.

That sounds like a strong argument for allowing more units. It is, but it also exposes the preservation problem.

At least 98 percent of those conversions to missing-middle housing involved demolition of the original house.

Permission for more housing changed what replaced the house. It did not usually save the house.

My read is that the retention bonus is an attempt to change that last step.

The owner gets something valuable: the ability to add housing. The city asks for something in return: keep the existing primary structure.

The feasibility study found that this approach can work for homeowners, small market-rate builders, nonprofits, and affordable-housing developers because the existing house still carries value. Avoiding a full demolition and replacement can reduce part of the project cost, while the added home or homes create another source of value.

That is the preservation bargain.

It is not preservation through a blanket prohibition. It is preservation through a more attractive alternative.

The distinction matters because zoning arguments often assume only two choices: freeze a block as it is, or clear lots for larger projects. Denver is testing a third path in which the existing house becomes part of the economics of adding supply.

The city’s construction data helps explain why it is interested in the trade.

Among new homes built from 2019 through April 2025 in the affected zoning areas, 82 percent of detached houses were larger than 3,000 square feet and 79 percent were appraised above $1.4 million.

By comparison, 74 percent of new missing-middle units were smaller than 3,000 square feet and 40 percent were appraised below $800,000.

Those figures do not mean every missing-middle home was affordable. An appraised value is not a sale price, and a home below $800,000 is still beyond many Denver households.

What the numbers support is a narrower conclusion: the missing-middle units were generally smaller, and a meaningful share occupied a lower price tier than the new detached houses built in the same broad zoning areas.

That can widen the range of choices without solving affordability by itself.

The feasibility study tested ownership housing restricted at 100 percent of area median income and rental housing restricted at 70 percent. Those were modeling assumptions, not final policy terms.

Some ownership scenarios reached the study’s feasibility thresholds. Many rental scenarios still showed financial gaps, especially when a developer had to buy land at market value.

The affordability bonus looked more workable for affordable-housing developers that already owned the land, acquired it below market value, or had access to subsidy.

This is an important limit. Zoning can make a project legal. It cannot make land, labor, construction financing, insurance, or materials inexpensive.

The city’s study is useful partly because it does not pretend the zoning text controls the whole outcome.

Interviews with builders and housing organizations identified permitting time, infrastructure fees, condominium liability, financing, and administrative complexity as continuing barriers.

Some retention scenarios also assumed the existing house needed no improvements. A real owner may discover foundation work, electrical upgrades, utility changes, access requirements, or repairs that substantially alter the calculation.

Access to capital matters too. A right that exists on paper is not equally usable by a homeowner with limited equity, a cash buyer, and an experienced developer.

There is also a reasonable risk that additional development rights become reflected in land prices. That is an inference, not a conclusion in the city’s study, and it is one reason the final details will matter. A preservation incentive works only if keeping the house remains competitive after the market prices the new option.