How We Increased Duplex Cash Flow 46% in 3 Years

The Situation

In 2018, the owner of this Denver duplex was done. The primary unit — a 4BR/2BA — had long-term tenants paying $2,200/month when the market was at $2,600. The secondary unit, a 2BR/1BA ADU was worse: tenants who'd started out fine had slipped into hoarding over time. Trash on every surface. Plumbing clogged. Rent at $1,300 on a unit worth $1,600.

The mortgage was covered, barely — but the property was falling apart. What should've been passive income had become something the owner dreaded dealing with.

The Strategy

We built a three-year plan around the fact that the two units were different problems.

The secondary unit needed money now — it wasn't rentable until we fixed it, so we went in with targeted renovations right away. The primary unit needed work too, but we'd pay for that out of the property's own cash flow over time. The owner didn't have to write a big check for both at once.

Step 1: Solving the Hoarding Problem

We went straight to the secondary-unit tenants. The unit wasn't rentable with them in it, and they needed to leave — but dragging it into an eviction fight would've cost more than it was worth. So we made them an offer: walk away clean within two weeks and we don't pursue legal action. They took it.

Step 2: Practical Renovation

Once it was vacant, we went through our standard process: pull out the damaged flooring and fixtures, put in vinyl plank throughout (durable, cheap, and clean-looking), repaint, refinish the bathroom and kitchen, service all the mechanical systems, replace the blinds and light fixtures.

Nothing fancy. It works.

Step 3: Marketing and Tenant Quality

We listed the renovated unit across multiple channels and screened for stable, long-term tenants. It leased at $2,000/month — a $700 jump from what the previous tenants had been paying. Getting the unit in good shape and marketing it well is what moved the number.

Step 4: Aligning Incentives with the Primary Unit

The family in the primary unit had been reliable for six years. We didn't want to force them out and deal with a vacancy, but we needed to get in and take care of the deferred maintenance. We were upfront about that — and it turned out they were already planning to move within the year anyway. They agreed to a one-year lease extension at a $100 increase (to $2,300) in exchange for letting us in on weekends to renovate room by room. No vacancy, no drama.

Step 5: Seamless Turnover

Over the course of that year, we worked around the family — new flooring and repairs on weekends. By the time they moved out, the unit was nearly done. It sat vacant for less than a month and re-rented at $3,000/month.

The Numbers

Monthly rents went from $3,500 to $5,000 — a $1,500 jump. Once the deferred maintenance was cleared, operating expenses stabilized too. Total monthly cash-flow gain: $1,800, a 46% increase.

Using a standard 144x rent multiple, the property's value went up by over $200,000.

What Actually Mattered Here

Three things:

Practical renovations. We didn't over-improve. Vinyl plank, fresh paint, working systems. The unit needed to be clean and functional — not impressive.

Creative problem-solving. Eviction is expensive and slow. We negotiated the problem tenants out instead. We gave the long-term tenants a reason to cooperate instead of forcing them out. Both moves saved money and kept the vacancy risk low.

Market-rate pricing. The owner had been taking below-market rents for years. Once the units were in shape and marketed properly, tenants paid market. That's what most owners miss.

The Takeaway

If you own a rental and it's generating stress instead of income — problem tenants, deferred maintenance, rents that are too low — the fix almost always comes down to the same three things: get the property in good shape, price it at market, and find stable tenants who'll pay for it.

This duplex is proof that the math works. If you're sitting on a property that's underperforming and want to talk through what a plan could look like, reach out. I'll walk you through what's possible on your specific situation.

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Paul McCoy, Realtor | Fathom Realty | License #: FA.100105533 | (319) 325-0668 | pmccoy626@gmail.com

Paul McCoy is a licensed real estate professional in Colorado. Equal Housing Opportunity.