Boulder Explained: Flat roofs, boxy shapes — why do Boulder’s new buildings all look alike?

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A reader asked: I’d like to know more about the process of approval of new construction, and why do so many large new buildings in the city look so ugly?

Whether or not new buildings in Boulder are “ugly” is subjective. But many large developments in Boulder do tend to look similar — flat, square and boxy, without major embellishments. Some resemble stacked wedding cakes: a square base with a smaller square on top.

We asked a few architects why. 

The short answer: time, cost and risk. 

Bouder’s site review process is known for being time-consuming and expensive. The longer a project takes, the riskier and costlier it becomes. To avoid delays, developers often stick to standardized designs that are more likely to be approved quickly. 

Another major factor is land value. Boulder’s real estate is among the most expensive in the country, and developers aim to maximize space — often resulting in boxy buildings. Height restrictions also play a role, virtually ensuring that larger buildings have flat roofs, according to Ryan Hanneman, an architect with RHAP Architecture and Planning. Boulder’s zoning code requires measuring a building’s height at its highest point, discouraging sloped roofs since they reduce usable interior space.

“You never leave any square foot behind,” Hanneman said. “You could say the same in Denver: Why is everything so massive and boxy? It’s because you have to max everything out to have it pencil out as a developer.” 

Risk is another major reason for the lack of architectural experimentation. Mayor Pro Tem and architect at HMH Architecture + Interiors Lauren Folkerts, explained that construction carries significant financial risks. Developers who start building an apartment today are betting it will be profitable years later when it’s completed. Any delays increase costs and add unpredictability, making the investment even riskier. “People are always looking for ways to mitigate that risk,” she said.

In Boulder, most large projects require site review, a discretionary process that allows developers to build outside city code but which introduces more uncertainty. “You could put in all this work to do this design, and someone might say, ‘No, we just don’t want that in our community,’” Folkerts said. 

The review process can take six months and be too costly for developers to afford to repeat. With so much at stake, developers rarely gamble on unique designs.

“Most of our clients avoid site review like the plague,” Hanneman said.

Developers also tend to work with the same architects who have successfully navigated Boulder’s process before. These architects, in turn, stick to design elements that have already been approved, reducing risk but limiting creativity.

“You’re stacking all of these different processes on top of each other where people can say ‘no’ to you. And in the past, they [the city] have said no quite a lot. So that makes the developer nervous,” Folkerts said. 

Ironically, site review was intended to encourage creativity by allowing developers to experiment outside standard code. But its unpredictability has had the opposite effect, according to some, pushing developers toward safer, conventional designs.

Additionally, in 2016, Boulder introduced more form-based code, which was meant to clarify design expectations. But instead of fostering originality, it imposes strict aesthetic guidelines — even specifying limits to window spacing down to the inch. 

“It’s very prescriptive,” Folkerts said. “Of course all the buildings built under that code are going to look very similar.” 

We’d be remiss not to mention some exceptions. The new North Boulder Library, designed by WORKac, has an unconventional shape made up of three long conjoined triangles, a variety of materials and a tube slide out the back. That city project began in 2018 and opened in 2024.

In another example, Boulder Housing Partners is converting the historic Geological Society office — a prairie-style, Brutalist building featuring exposed concrete partially composed of gravel from the Boulder Creek floodplain — into affordable housing, while maintaining many of the building’s unique design elements.