Guest blog by YIMBY Action's Denver Chapter Lead, David Pardo
When I joined YIMBY Denver in 2019, most of our organization's energy was directed toward supporting individual rezonings for apartment buildings. Over the next few years, we graduated to broader local and state advocacy. We legalized accessory dwelling units, ended occupancy limits that prevented people from sharing their homes with roommates, and legalized single-stair buildings, first in Denver and then throughout Colorado.
Denver is now looking to relegalize traditional building forms through a program called Unlocking Housing Choices, which would allow cottage courts and plexes on all residential lots. At the state level, bills to allow lot splitting and reduce minimum lot sizes both failed this year but are likely to return next year.
All of these are great achievements that have helped to drop rents in the Denver area, but now, in Colorado, California, and across the country, we’re beginning to see the next hurdles to increasing supply and reducing housing costs: building codes, related construction rules, and outdated or suboptimal standards.
Right now, single-family homes, side-by-side duplexes, and townhomes are built under local adoptions of the International Residential Code (IRC), but if a building has multiple units (like a fourplex), it must be built in accordance with the International Building Code (IBC) and related rules, which can add $30-$50 per square foot to construction costs without improving the safety, durability, or habitability of smaller multifamily homes.
Some states (North Carolina and Alaska) and cities (Houston and Memphis) have already moved 3-8-unit structures under their IRC adoptions, allowing for more single-level homes suitable for our growing senior populations, as well as legalizing the types of plexes we used to build throughout our country that fit better into neighborhoods than large apartment buildings. These reforms would also ease the conversion of larger existing homes into multiple units, allowing renovators to convert existing structures into multiple small apartments rather than just more expensive versions of their prior forms.
Elevator reforms, which allow simpler, smaller, and more standardized elevators, could reduce the cost of individual elevators from nearly $200,000 to roughly $50,000 (the cost in Italy). This would help to ensure that single-stair buildings can host seniors and disabled neighbors above their ground floors, making moving in, carrying groceries, and ferrying young kids into the family-sized apartments easier and more convenient.
In addition to single-stair, elevator, and building code fixes, there is also sprinkler simplification. Right now, the National Fire Protection Association (NFPA) has rules for sprinkler systems in three flavors (13D, 13R, and 13), which specialized contractors must install. 13D is only allowed in IRC-type structures, whereas 13R is required even in a fourplex, and 13, which is targeted at high-rises and may require pumps with backup power, is required in many medium-sized buildings, such as the currently proposed 5- and 6-story single-stair buildings.
Simpler and cheaper sprinkler systems designed to a prescriptive section of the IRC, known as P2904, can be installed, but are not widely used. They can be installed by regular plumbers using easier-to-work-with PEX piping, at lower cost and with less maintenance. Automatic fire extinguishers, which eliminate the potential for water damage from a leaking or activated water-filled sprinkler system, can be installed over stoves, the ignition source for more than half of house fires, in homes without sprinkler systems. These are both great alternatives for neighborhood infill or gut-renovation projects with limited budgets.
Plumbing, Heating, and Air Conditioning codes are also areas where improvements to our rules could increase housing supply. Europe and Asia require fewer vent pipes for their plumbing systems without compromising safety or comfort, while also allowing bottle traps and other fixtures that reduce complexity and cost for plumbing installations. Europe allows heat pumps that use R290 (high-purity propane) as the refrigerant, which is much cheaper than existing refrigerants and has lower environmental impacts due to its greatly reduced global warming potential.
Finally, our rules regarding electrical systems need work. Right-sizing calculations related to expected loads in electrical codes would allow owners to electrify existing buildings without expensive panel upgrades. New technologies make it easy for a home to be networked to the power company and to cut off large loads like EV chargers and electric water heaters during energy spikes, which will reduce the need for new power plants, save on transmission upgrade costs, and lower end-user energy bills without noticeable changes. A water tank dropping from 120F to 118F over 20 minutes during peak times of day, or an EV not charging for 20 minutes at peak periods in the evening, is a non-issue for renters and homeowners, but it can save tens of thousands of dollars in panel and service upgrades for a fourplex, and millions of dollars in network upgrades for the power company, which shows up on people’s bills in perpetuity as those capital investments get amortized.
Thus, even after passing Unlocking Housing Choices in Denver or SB9 in California, there is still plenty of work to be done to increase housing production through smaller but impactful technical changes. I highly recommend that YIMBY members join their local building code committees and push lawmakers in their statehouses to make these technical changes to building codes. We’ve already passed high-impact zoning reforms that had significant organized opposition. We can’t stop when much of what’s left is simple code cleanup, with nobody guarding the proverbial net.
This post was written by David Pardo, a policy and steering lead with YIMBY Action's Denver chapter, with assistance from Stephen Smith, the Executive Director of the Center for Building in North America, Robert Greer and Kevin Matthews, two other YIMBY Denver leads, and Joh Gehlbach, YIMBY Action’s Senior Campaigns Manager.