Understanding Chevy Chase's Proposed FAR Ordinance

Much of this summary is based on the Town of Chevy Chase’s Land Use Committee’s report. The clarity of the report greatly assisted my efforts.

This post explains the concept of FAR and how it is measured in the Town of Chevy Chase's proposed ordinance.

The Basic Idea

The Town of Chevy Chase’s Land Use Committee has proposed a building ordinance which would limit the maximum size of homes based on Floor Area Ratio (FAR), the gross floor area of a building divided by lot size. FAR limits the bulk or volume of a building but allows for more flexibility in building design than limits based primarily on lot coverage or height which tend to result in box-like structures.

The base FAR proposed for Chevy Chase is .30 which would permit a 3,000 square foot home on a 10,000 square foot lot. The Land Use Committee has proposed giving bonus FAR for homes that adhere to certain performance standards or incentives. New construction (i.e. teardowns) could have an FAR as high as .45 which would allow for a 4,500 square foot home on the same 10,000 square foot lot.

The Committee has proposed a maximum FAR of .50 for houses with additions. At this FAR, one could construct a 5,000 square foot home on a 10,000 square foot lot. The purpose of a higher FAR for homes with additions is to provide an incentive to retain existing homes and preserve the Town’s character.

Why FAR Tends to Underestimate What You Can Really Build

The figures cited above tend to underestimate greatly the permitted floor space within any building except on really large lots. Here is why:

Minimum of 2,500 Square Feet Allowed
No matter how small your lot, you can still construct a house of 2,500 square feet. Small lots are thus protected and given a bonus over large lots in terms of permitted floor space.

Below-Ground Floors Usually Don’t Count Toward Allowed Floor Space
Many below-ground areas thought of as basements by most people are legally classed as cellars. In general, if over one-half of the below-ground level is below the average elevation of the finished grade, this area is classed as a cellar as does not count toward your allowed floor space.

For example, my home contains a finished basement. Since it is clearly well more than 50% below grade, it is legally classed as a cellar and doesn’t count toward my total permitted floor space.

Unenclosed One-Story Porches Don’t Count Toward Allowed Floor Space
Porches are part of many existing homes in the Town. In order to help protect them and encourage their inclusion in new construction, the Committee recommended that unenclosed one-story porches not count toward your allowed floor space.

First 240 Feet of Detached Accessory Structures Don’t Count
This exemption is designed to encourage the preservation of detached rear garages which are characteristic in many parts of the Town. Caution: If you build an addition which attaches them to your home, then the first 240 feet will count as they are no longer an accessory structure.

Attics Count Only If They Have Structural Headroom of 6 Feet, 6 Inches
In other words, more traditional short attics don’t count toward the floor space limit.

Many Projections from the Home Don’t Count
For example, bay windows don’t count toward the allowed floor space unless they run from the bottom to the top floor of the house.

A Couple of Important Caveats Which Limit Home Size

Maximum of 5,000 Square Feet Is Allowed
Even if your FAR theoretically allows you to build more, you can only build up to a maximum of 5,000 square feet. However, remember that this limit excludes all of exceptions mentioned above which do not count toward the limit. A below-grade basement, for example, could greatly expand the useable space in such a home.

Two-Story Rooms Are Counted Twice
Even if a floor isn’t laid, two-story areas (defined as 14 feet or higher) are counted twice under the recommendation, so you don’t get a break for cathedral ceilings. This makes sense since the goal of the Committee’s recommendation is to limit the bulk of homes. You can’t double your home size by having extra-high ceilings in every room.

My second post on the proposed ordinance discusses incentives which permit a homeowner to receive a higher FAR.