What the key site and zoning numbers mean.

Floor area ratio (FAR)

FAR compares a building’s counted floor area to the lot area. A 50% FAR on a 6,400 sq ft lot suggests up to about 3,200 sq ft of counted floor area before exclusions, bonuses, or other code provisions.

It does not tell you the building footprint. A two-story 3,200 sq ft home might have a footprint near 1,600 sq ft; a one-story home with the same floor area would need much more ground area.

Lot coverage

Lot coverage is the share of the lot covered by buildings and, in some jurisdictions, other defined improvements. A 50% limit on a 6,400 sq ft lot is a preliminary cap of about 3,200 sq ft.

Setbacks, easements, tree protection, and the city’s specific definition of “coverage” can make the usable footprint much smaller. It is not a guarantee that the full percentage can be placed anywhere on the lot.

Impervious surface

Impervious surface generally means ground that does not readily absorb water, such as roofs, driveways, patios, and walkways. It matters for drainage and stormwater requirements.

Impervious surface and lot coverage can overlap, but they are not interchangeable. A feasibility study uses a city’s published standard as an early screen; a civil engineer confirms the actual areas from a site plan and drainage design.

Height

Height is measured using a city-specific method—often from average building elevation, finished grade, or another defined point. A “25 ft” maximum is therefore not a simple tape-measure limit from the street or the lowest corner of the lot.

Setbacks and buildable envelope

Setbacks are required open areas from property lines. After setbacks, easements, critical-area buffers, utility areas, and tree protection are accounted for, the remaining area is the practical buildable envelope. That envelope needs a current survey and site-specific design review to confirm.

How to use the numbers

1. Open the Source link beside each feasibility-study metric to see the underlying public map or code.
2. Use the numbers to compare concepts and decide what to investigate first—not to finalize a house size.
3. Before committing to a purchase, design, or permit path, confirm the site with the city plus an architect, licensed surveyor, geotechnical engineer, arborist, and civil engineer as applicable.

Build Eastside feasibility studies are preliminary screens based on publicly available data. They are not confirmed feasibility, a survey, tree inventory, geotechnical opinion, engineering design, code interpretation, or permit approval.