Costs: What a Denver Second-Story Addition Costs in 2026

The short answer

For a typical Denver pop top in 2026, plan on between $450 and $575 per finished square foot for the new upstairs space. Across the whole project that lands between $250,000 and $775,000. What you add, and how far the work reaches down into the house you already have, drives most of that spread.

Add a primary suite plus a bedroom or two, call it 800 to 1,200 square feet upstairs, and you are usually looking at $440,000 to $650,000.

Treat these as a place to start. A real quote comes from a builder who has stood in your house. Two homes on the same block can come in six figures apart for reasons that have nothing to do with the finishes.

What that buys, by size

You add	Rough finished area	Typical 2026 range
A primary suite	~500-700 sq ft	$250k-$390k
A suite plus one or two bedrooms	~800-1,200 sq ft	$440k-$650k
A full second floor over the whole footprint	~1,200-1,800 sq ft	$650k-$775k+

Cost per square foot drops as the addition grows. The costly fixed work happens once. Pulling off the roof and reinforcing the frame runs about the same whether you add 600 feet or 1,600, so a bigger addition spreads that money over more room.

What moves the price

Square footage is only the opening figure. Here is what separates a $340,000 bid from a $615,000 one on additions of about the same size.

Structure and foundation

A second story is weight the original house was never built to carry. In Denver's older brick bungalows, an engineer can find that the foundation or the main-floor walls need reinforcing. That work vanishes behind the finished walls, but it can add a great deal to the bill.

How much of the main floor gets touched

The cleanest pop tops leave the ground floor alone. A staircase has to land somewhere, and once you open the main floor to fit one, redoing the kitchen while the walls are already open starts to look sensible. A second-story addition slides into a whole-house remodel this way, and the budget can double.

Systems

A bigger house asks more of its mechanical systems. A larger furnace, a heavier electrical panel, a water heater that can serve another bathroom, sometimes a fatter service line from the street: none of it shows up in the room you are picturing, and all of it costs.

Finishes

Across 1,000 square feet, the gap between builder-grade and high-end finishes reaches $85,000 to $170,000. This is one you largely control.

Where you live during construction

A pop top runs about 8 to 14 months. A few of those go to design and permitting, then most of a year goes to construction, and for a good part of it the house is open to the weather. Plenty of families move out for a stretch, so put six months or more of rent in the budget.

Costs that surprise people

• Design and engineering. Architectural drawings and a structural engineer can come to 5 to 10 percent of the project.
• Permits and fees. Denver's review and permit costs climb with how much the work is worth.
• Code upgrades. Pull a major permit and in some cases parts of the existing house may have to meet current code.
• Landscaping. A year of heavy construction is hard on a yard, consider if now is the time for a landscaping refresh as well.

Hold back 10 to 15 percent on top of the bid. On a job this size, something behind the walls will surprise you, and you want the cash ready when it does.

Keeping the number down

There are real ways to hold a pop top budget down without gutting what matters. Designing inside the footprint you already have is the biggest one. You can also phase the finishes over time, and stay disciplined about scope creep on the main floor once those walls are open. Each of those earns a longer look, and the guide to controlling pop top costs walks through them one at a time.

A pop top costs a lot, but so does every other way of getting the space. Moving to a bigger home takes agent commissions, closing costs, a higher price per foot, and uprooting from the neighborhood you picked in the first place. For plenty of Denver families on a lot they love, especially those holding a great mortgage rate, the second story comes out ahead.

See it before you price it

Looking at homes that have already done it is the fastest way to size up what your money buys. Browse the gallery of real Denver pop tops to see finish levels across neighborhoods, or check what's being built right now to find projects near you.

When a rough budget needs to become a real one, the next step is a builder who has done additions like these.