When is Big Too Big?

County addressing infill housing and lot coverage

Renovation or McMansion? While much infill development is healthy and a welcome investment in our community, Arlington residents have expressed strong concerns about the undesirable effects of certain infill development—building on vacant lots or redeveloping parcels within established neighborhoods. As a result, the County Board is considering changes to Arlington’s Zoning Ordinance that decrease the amount of a residential lot that can be covered by houses, accessory buildings and driveways, known as “lot coverage.”

For example, on a lot zoned R-6, if the area occupied by the buildings and driveway is 2,400 sq. ft. and the total lot is 6,000 sq. ft, the coverage would be 2,400 divided by 6,000 or 40 percent. The maximum allowable lot coverage in Arlington is 56 percent for all five of the County’s residential zoning districts regardless of lot size, which allows oversized, out-of-character homes to be built right next to smaller homes. Based on a Planning staff analysis, very few homes approach or exceed 56 percent coverage.

This issue has generated a great deal of public interest in the community, and some confusion, as well. Staff has recommended that it be deferred until the June 6 Planning Commission meeting and the June 18 County Board meeting.

Residents’ concerns

In recent years, the Board has received numerous complaints from residents about infill development, including loss of open space, bulky and incongruous homes that are incompatible with neighborhood character, loss of separation between houses, visual intrusions, loss of trees, and more area devoted to parking and driveways. Arlington is a largely “built out” community, and when new single-family homes are constructed here, often it is on lots previously occupied by homes. In the case of larger lots, sometimes one older home might be torn down and replaced by two or more houses. Few new residences are built on vacant lots.

What’s been done so far: Lot coverage studied

Over the past few years, responding to residents’ concerns, the County Board has directed the Zoning Ordinance Review Committee (ZORC) and Planning Division staff to research and recommend amendments to the Zoning Ordinance to address certain undesirable effects of infill development on established neighborhoods. To date, amendments have been adopted addressing building height, setbacks and pipe-stem lots. Lot coverage is the fourth issue identified and the only one remaining. A study was undertaken to determine reasonable coverage limits that would protect neighborhoods from very large houses in the future while still allowing reasonably sized houses for today’s market. At this point there are two options before the County Board, both incorporating a “sliding scale,” yet differing on the application of the sliding scale.

Option #1: New coverage rules apply to all properties

Establish a sliding-scale requirement that would reduce overall coverage in each of the five districts zoned for single family residences, but allow larger coverage on smaller lots. For example, this would reduce the maximum coverage from 56 percent to 45 percent for the R-5 district (the smallest) and from 56 percent to 20 percent for R-20 (the largest). Coverage limits for the other three districts—R-6, R-8 and R-10—also would be reduced similarly as follows:

• 45 percent in R-5 zoning districts, to 25 percent in R-20.
• 48 percent in R-5 to 28 percent in R-20 (with front porches).
• 50 percent in R-5 to 30 percent in R-20 (with detached rear garage)
• 53 percent in R-5 to 33 percent in R-20 (with a front porch and rear garage)

This option also proposes a zoning ordinance amendment to limit the main building footprint size and a maximum main building footprint cap for oversized lots. Five percent additional coverage would be permitted for detached garages located in rear yards and 3 percent additional coverage for front porches—so as not to discourage these desirable features. Main building footprint coverages and caps would vary as follows:

Maximum main building footprint coverage ranges

• 34 percent in R-5 to 16 percent in R-20
• 37 percent in R-5 to 19 percent in R-20 (with front porch)

Main building footprint cap

• 2040 square feet in R-5 to 3,880 in R-20
• 2200 square feet in R-5 to 4610 in R-20 (with front porch)

If approved, this recommendation would apply to all existing residences, new construction and substantial additions and renovations. It also would allow a main structure that was destroyed by fire or calamity to be rebuilt to its original coverage, even if that exceeds the new coverage limits.

Option #2: New rules apply to new construction or major additions

The County Manager’s recommendation differs from Option #1 in one distinct way. The new coverage requirements reflected in the sliding scale would only apply to new home construction and substantial modifications of existing houses, i.e., additions that more than double the existing main building footprint, or remove more than 50 percent of the existing exterior walls. This alternative would still deal with the most egregious examples of overbuilding. However, it would avoid any unintended consequences for existing homeowners, such as limiting their ability to build appropriate additions.

For further information

For an in-depth discussion of these issues, please visit the Dept. of Community Planning, Housing and Development’s Web pages, accessible from the County’s homepage, www.arlingtonva.us/lotcoverage.

County Planning staff has been making presentations to the Neighborhood Conservation Advisory Committee and several civic associations. For more information or to request a presentation to your civic association, a hotline has been established: (703) 228-4793. Homeowners may also call with questions and for help determining if specific properties would be in compliance with the proposal.