Minimum Lot Sizes
In order to have by-right development, a lot must meet the minimum lot size of the zoning district. Every lot that doesn’t meet the minimum lot size is immediately kicked out of the compliance model and doesn’t count towards our density total.
In order to get 90% of lots in our district into compliance and therefore to count towards our total unit density we had to choose a new minimum lot size, based on the existing lots in our proposed district. The new minimum lot size is 5,000SF for the Mixed Residential district. This is based on our analysis below/
Frontage is the measurement of the portion of a lot that “fronts” the street. The new minimum frontage will be 60ft in the Mixed Residential district, as this number brings ~85% number of lots into compliance.
Required Yard Setbacks
A required setback sets a minimum distance that any structure can be from the edge of a property. Setbacks are measured from the lot lines, not from the street or sidewalk, and are typically set around all edges of a lot. This guarantees some distance between neighbors and to have minimum required yard space visible from the street.
Because we want any potential future development to be complementary to the existing structures in our zone, we started our analysis of appropriate required minimum setbacks from the existing single-family setbacks. However, the existing setbacks in our single-family districts assume that all lots meet the district minimum lot size. When those setbacks are applied to real lots, like those in our district ranging from 5,000SF to 12,000SF, the setbacks are too restrictive on the small lots and kick them out of the compliance model. In order to get the smallest third of our existing lots into compliance, setbacks must be reduced from the existing single-family ones. Thus, our proposed setbacks are as follows:
- Required minimum front yard setback = 10ft
- Required minimum side yard setback = 10ft
- Required minimum rear yard setback = 15ft
When we did an informal survey of existing homes in our proposed district, existing front setbacks ranged from 5ft to 30ft+. Many appeared to be or were lower than the current requirement of 20ft in the zone, which was put in place far after most of these homes were built.
Those building new structures are, of course, always welcome to put them farther back the required minimum setbacks, these numbers are simply the closest to the lot line any new structures can be.
Maximum Coverage % of a Lot
Maximum lot coverage is the total area of the footprint of all of the buildings on a lot. Max lot coverage includes a primary building, any detached garages, sheds, or other accessory buildings.
We propose a general maximum lot coverage of 30% in the Mixed Residential District. We’ve taken the current single-family lot coverage of 25% and slightly increased it. The slight increase in maximum lot coverage assists us in bringing the district into compliance while still acting as a powerful limiting factor reducing the building footprint to reflect a more “house-like” lot design.
30% maximum lot coverage is still a very low lot coverage for multi-family housing; many other cities start at 40% lot coverage for multi-family housing and go up from there. Having a lower lot coverage percentage that is more in line with single-family coverage percentages reflects that residents wanted new units to complement the existing single-family nature of the areas in our district.
The max lot coverage is the primary restriction on overall building size within the district.
Maximum Building Height
We propose keeping the current maximum building height that is allowed in our Single-family residential zones, which is 35ft. A max building height of 35 feet would allow 2-4 stories, depending on the slope of the lot and the desired height of each floor.
Maximum Density Per Acre
One of the goals in our district design is to meet the requirements of the law but also limit the potential build out of lots. Given the wide range in lots sizes over the geography of our new district the density limiting factor we chose was to set a maximum density of 22 units per acre to be allowed by-right. This allows the number of units allowed to scale with the size of the lots, while acknowledging that 85% of our lots are 15,000 SF or less, meaning under the new zoning those lots could have 3 to 8 units—more detail in the table below.
Because of how the state calculates density within our compliance district, setting a 22 units per acre maximum density actually delivers a compliance density just above the required 15 units per acre.