Portland’s zoning allowances use measurable standards such as limits for height, lot coverage, setbacks and yard area to define a building envelope that limits how large a single family house can be on a lot. While the building envelope allowance has remained relatively unchanged, the size of houses built has increased steadily as a nationwide trend. Larger homes can result in loss of space for yard, gardens or trees; more shading on adjacent lots; greater energy and material consumption; and less neighborhood compatibility.
Building coverage regulations and height limits currently control house size. On a 5,000 square foot lot for example, the maximum building coverage is 2,250 square feet and the maximum height is 30 feet.
|Comparison of house sizes on 5,000 square foot lots|
|Maximum building coverage allowed (square feet)||Maximum height (feet)||Maximum house size allowed (square feet)||Average house built in 2013 (square feet)||Largest house built in 2013 (square feet)|
|2,250||30 (three stories)||6,750||2,680||4,461|
The proposal would add a new square foot limit via a sliding scale tied to lot size.
|Proposed house size limits based on lot size|
|Lot size (square feet)||2,500||5,000||7,500||10,000||12,500|
|Proposed house size (square feet)||1,750||2,500||3,000||3,500||3,750|