Boulder’s rules are complex and constantly changing. When you show a property to your client, unless they love the house exactly the way it is, they probably have asked you, “Can I do x with my property? Add an ADU? Pop the top? Convert the garage into living space? Scrape?” There are hundreds of questions – I’ll cover some of the most commonly asked ones here. In subsequent months’ articles I’ll go into greater depth with some of the most common questions, but here’s a quick primer to help you know how to answer the big ones.
City of Boulder:
· Size: Every lot in the city has a maximum Floor Area Ratio and maximum Building Coverage; these numbers are based on the zone and the size of the lot (to find out yours, Google those words and it will take you to the city’s calculator). There are no exceptions except for historic properties. Note that a certain portion of the basement will count if it’s exposed above grade. Many homes in Boulder are already maxed out.
o In 2010, the Compatible Development Ordinance drastically reduced the development capacity of most lots in Boulder.
· Height: Many sloping lots in Boulder are actually restricted to one story (plus possibly a walk-out basement). A licensed surveyor must map the topography and find the lowest point where the house meets the land, draw a 25 ft. radius, and the lowest point in that radius is your “Low Point”. No part of the house (other than the chimney) may exceed 35 ft. above that (20 ft. for detached accessory buildings). No exceptions.
o Additionally, Solar Shadow restrictions that prevent a property from shading its neighbor can often further limit a house’s ability to go up, especially close to the property lines. This can get particularly restrictive on narrow or north sloping lots.
· Massing: There are strict and overlapping rules for the setbacks, bulk and even the shape of the house above and beyond height and solar shadow restrictions.
· Floodplain: If you’re in the 500 year flood zone, no worries. In the 100 year, if the new/remodeled construction exceeds 50% of the assessed value of the house (not the total property), or if an addition exceeds 50% of the entire house, the entire house must comply with FEMA’s new construction rules. This mostly affects the required elevation of habitable floors, which can sometimes mean that it’s almost impossible to meet the FEMA requirements. There are a host of other rules, but that’s the most common serious issue. If you’re in the “Conveyance Zone,” you are extremely limited on what you can do. In the high-hazard zone, ‘fuggedaboutit.’
· Historic: If a property is over 50 years, it is potentially eligible, but in reality, unless a historically significant person lived there or created it, it’s a ‘contributing’ structure in a historic district, or it’s a very special example of a particular style of architecture, it is unlikely to be landmarked unless it was built prior to WWII. Importantly, the City does not consider its current condition in its determination. They do, however, eliminate it from Landmark consideration if it has been significantly altered.
· ADU’s & OAU’s: only allowed in certain zones and are subject to a host of rules about size, parking, design, owner’s residency and connection to the main house.
· Green building: the value of any new construction (relative to the value of the existing house) triggers increasingly robust levels of green building requirements. In many large remodel/additions of older homes, it can force the entire home to comply with “new home” requirements. In some cases, this means the near demolition of the house.
Boulder County:
· Size: all new homes, additions over 1000 s.f., and any addition to a home that is larger than the Presumptive Maximum Size (PSM) have to go through Site Plan Review (SPR) before submitting for building permit. You start with an SPR “Pre-app meeting,” where the planner will tell you what your PSM is. It’s 125% of the median of all homes in a 1500 ft. radius. Basements, garages, and all non-ag structures count. Exceptions are possible, but are rare and hard to win.
· Height: 30 ft. Although this is less than the City because they measure straight down to the dirt below that portion of the home, nearly all homes in the County can be at least two stories.
· Materials: The County regulates exterior materials both for visual impact and fire-resistance. In the mountains, wood is largely prohibited on the exterior.
· Access: Not all legal building lots are buildable and the most common obstacle is the driveway. A Civil Engineer and a survey are required determine if a legal driveway can be built.
· Historic: similar to the City
· Flood: Floodway bad. Floodplain less bad. Equivalent to the high hazard/conveyance zone & 100 year zones in the city respectively.
· Green building: Similar to the City. Increases in rigor as the scope of work increases.
A few important final notes:
· Just because a neighboring house did it, doesn’t mean you can (likely it was built prior to the newer codes). Every property only has to comply with the rules that were in place at the time of their application. The rules are constantly getting stricter.
· Properties that are in a P.U.D. (like Devils Thumb or Wonderland) may have rules that supersede standard zoning rules.
· Properties that have an HOA typically comply with both the municipality’s rules and the HOA’s. In some cases the HOA is more restrictive.
· Surrounding towns have totally different (and easier) rules.
About the author:
Scott Rodwin, AIA, LEED AP is the owner of the Rodwin Architecture/ Skycastle Construction, a 13 person award-winning design/build firm specializing in high-end custom green homes in Boulder. He teaches a free course (good for 2 CEU’s) called “Understanding the Rules for Building in Boulder” through BARA several times a year that goes into depth on these topics. [email protected] www.rodwinarch.com
Read the full Article here (p.10)