Standards related to the building envelope also regulate the height of homes and the distance houses are set back from the property line.

The method currently used to determine a house’s height can result in new homes that are taller than surrounding dwellings, impacting shading and privacy.

Setbacks maintain light, air, privacy and separation for fire protection while reflecting nearby placement patterns of houses. When houses built to minimum allowed setbacks are out of alignment with houses on either side, block patterns can be disrupted.

Height


What is currently allowed

Each single-dwelling zone has a maximum building height (30 feet in most zones, 35 feet in the R2.5 zone). Two reference points are needed to determine a house’s height: a bottom base point and a top reference point, which do not have to be in alignment with one another. The top point is measured at either the highest point (on a flat roof) or the midpoint (on a pitched or “gabled” roof). On most lots, the bottom base point is measured from the highest grade five feet away from an exterior wall. This method can have the effect of a much taller wall on the downhill side and is also susceptible to manipulating adjacent ground to establish a higher base point to increase a house’s height. Lowered house roofline graphicClick to enlarge

Proposal: Lower the house roofline.

  • Measure from the lowest point 5 feet from a house, not the highest point
  • Retain current measurement to midpoints of pitched roofs and to the tops of flat roofs
  • Reduce the height of flat roofs by 5 feet to lessen undesirable shading impacts
  • Limit dormer projections that are over height limits to 50 percent of roof length

HOUSES ON STANDARD LOTS: The draft proposal would reduce the maximum allowed height of flat roofs from 30 to 25 feet. This minimizes impacts of shading on adjacent properties. The draft proposal would not affect houses with pitched roofs.

HOUSES ON NARROW LOTS: The draft proposal would establish a single height limit for all narrow lots. The maximum allowed height for pitched roofs would become 23 feet. The maximum allowed height for flat roofs would become 20 feet. This draft proposed change still allows for two-story houses.

ATTACHED HOUSES: The draft proposal establishes a maximum allowed height of 30 feet for pitched roofs and 25 feet for flat roofs in all cases.

DORMERS: The proposal would allow dormers (limited to 50 percent of the length of the roof) to project beyond the maximum allowed height. This limit intends to prevent dormers from significantly affecting the scale of a house.

Setbacks


What is currently allowed

In most single-dwelling zones, houses must be set back at least 10 feet from the front property line and 5 feet from all other property lines. Certain building features, such as eaves and bay windows, are allowed to project into setbacks to create articulation and accentuation that helps break up scale and allows for more diversity of building styles. Current code allows these features to project up to 20 percent (typically one foot) into side setbacks.

Typical setbacksClick to enlarge

Typical building setback minimums for most single-dwelling zones

Typical setbacksClick to enlarge

Narrow eaves, common in many new Portland houses, are often the result of current code limits.

Typical setbacksClick to enlarge

Wider eaves help to reduce the perceived scale of a house. Bay window projections also help to break up the massing of building walls. 

Proposal: Make front setbacks consistent with setbacks on existing, immediately adjacent homes.

  • Increase minimum front setback by 5 feet (to 15 feet) with exceptions for matching front setbacks on existing, immediately adjacent homes
  • Retain current side and rear setback minimums (5 feet for most homes)
  • Allow eaves to project 2 feet and bay windows to project 18 inches into setbacks

Proposed Setback 1Click to enlarge

In R2.5 and R5 zones, for example, the draft proposal establishes a new minimum allowed front setback of 15 feet, five feet more than what is currently required.

Proposed Setback 2Click to enlarge

The draft proposal also has an exception that allows new or remodeled houses to match the setbacks of existing, immediately adjacent homes.

Proposed Setback 3Click to enlarge

Increasing front setbacks for new or remodeled houses generally affords for larger front yards and landscaping. However, allowing these houses to match the setbacks of existing, immediately adjacent houses also gives flexibility to better ensure compatibility with older homes on a block.

Download the Residential Infill Project draft proposal booklet.