Statutes, codes, and regulations
District Of Columbia Administrative Code
Title 12 - CONSTRUCTION CODES SUPPLEMENT OF 2017Subtitle 12-A - BUILDING CODE SUPPLEMENT OF 2017
Appendix 12-A-G - FLOOD-RESISTANT CONSTRUCTION
Rule 12-A-G801 - OTHER BUILDING WORK

D.C. Mun. Regs. tit. 12, app 12-A-G r. 12-A-G801

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Current through Register Vol. 71, No. 52, December 27, 2024
Rule 12-A-G801 - OTHER BUILDING WORK
G801.1

Garages and accessory structures. Garages and accessory structures located wholly or partially within flood hazard areas shall be designed and constructed in accordance with ASCE 24 and comply with the following conditions as applicable.

G801.1.1

DOEE covenant required. No permit to construct or to make substantial improvement in an accessory structure located wholly or partially within a flood hazard area will be issued by the Department without evidence of DOEE's approval of a non-conversion agreement not to convert the accessory structure to a residential use.

G801.1.2

Size Limitation. No code modifications or variances will be granted to allow an accessory structure located wholly or partially within a flood hazard area to exceed 600 square feet (55.74 m2).

G801.1.3

Exception to Chapter 16 requirements for certain accessory structures.

Accessory structures that are less than 600 square feet (55.74 m2) in area and are not elevated or dry floodproofed in accordance with Chapter 16 of the Building Code are allowed where the accessory structure meets the following conditions:

1. Constructed with flood damage-resistant materials below the design flood elevation;
2. Constructed and placed to offer the minimum resistance to the flow of floodwaters;
3. Anchored to prevent flotation;
4. Electrical service and mechanical equipment elevated to or above the design flood elevation; and
5. Provided with flood openings that meet the following criteria:
a. There shall be a minimum of two flood openings on different sides of each enclosed area; if an accessory structure has more than one enclosure below the lowest floor, each such enclosure shall have flood openings on exterior walls;
b. The total net area of all flood openings shall be at least one square inch for each one square foot of enclosed area (non-engineered flood openings), or the flood openings shall be engineered flood openings that are designed and certified by a licensed professional engineer to automatically allow entry and exit of floodwaters; the certification requirement is allowed to be met by the professional engineer's certification or by submission of an Evaluation Report issued by the ICC Evaluation Service or another approved entity;
c. The bottom of each flood opening shall be one foot or less above the higher of either the interior floor or grade or the exterior grade immediately below the opening; and
d. Any louvers, screens, or other covers for the flood openings shall allow the automatic flow of floodwaters into and out of the enclosed area.
G801.1.4

Underground garages in basements. Underground garages located in basements (for flood loads) of an existing or proposed building or structure that:

(a) is located on a development site wholly or partially within a flood hazard area, and
(b) is used or will be used partially for Residential Group R occupancies, including a mixed use building with Residential Group R occupancies, will not be approved in permit applications for new construction or substantial improvement, without a code modification granted pursuant to Section G105.
G801.2

Fences. Fences in floodways that may block the passage of floodwaters, such as stockade fences and wire mesh fences, shall meet the requirement of Section G103.4.

G801.3

Oil derricks. Oil derricks located wholly or partially in flood hazard areas shall be designed in conformance with the flood loads in Sections 1603.1.7 and 1612.

G801.4

Retaining walls, sidewalks and driveways. Retaining walls, sidewalks and driveways located wholly or partially within flood hazard areas shall meet the requirements of Section 1804.5.

G801.5

Swimming pools. Swimming pools located wholly or partially within flood hazard areas shall be designed and constructed in accordance with ASCE 24. Above- ground swimming pools, on-ground swimming pools and in- ground swimming pools that involve placement of fill in floodways shall also meet the requirements of Section G103.4.

G801.6

Decks, porches, and patios. Decks, porches and patios located wholly or partially within flood hazard areas shall be designed and constructed in accordance with ASCE 24.

G801.7

Roads and watercourse crossings in regulated floodways. Roads and watercourse crossings that encroach into regulated floodways, including roads, bridges, culverts, low-water crossings and similar means for vehicles or pedestrians to travel from one side of a watercourse to the other, shall meet the requirement of Section G103.4.

D.C. Mun. Regs. tit. 12, app 12-A-G r. 12-A-G801

Final Rulemaking published at 67 DCR 5679 (5/29/2020)