This guideline is intended to provide the homeowner/contractor with the basic information needed to apply for a building and trade permits to finish or partially finish most residential basements. You will need to fill out applications for the building, electrical, and if applicable plumbing and a mechanical permits.
Submit two (2) complete sets of detailed building construction plans drawn to 1/4" = 1'-0"scale and containing the following:
General Plan Preparation Information
The building construction plans need to identify existing and new construction. Show basement area room layout and identify use of each room/space by name and indicate both new and existing walls/partitions. Basements with Habitable space and every sleeping room must have at least one emergency escape and rescue window or door opening for emergency escape and rescue. i.e. a door to the exterior or a window and window well meeting the egress requirements of section R-310 of the 2000 International Residential Code. The emergency escape window shall be operable from the inside without the use of special knowledge, tool, or extra force, beyond that required for normal window operation.
Habitable Room Sizes & Ceiling Heights
- Habitable rooms shall have an area of not less than 70 square feet and shall not be less than 7 feet in any dimension.
- Habitable rooms, bathrooms, hallways, and laundry rooms shall have a minimum ceiling height of 7'-0".
- Finished box-outs for structural or decorative beams, ductwork, plumbing and electrical systems shall have a minimum clearance of 6'-6", with a spacing of not less than 4'-0" on center.
Emergency escape and rescue Openings: Section R-310 of the 2000 International Residential Code requires that all sleeping rooms and basements with habitable space shall have at least one openable emergency escape and rescue opening. Emergency escape and rescue openings shall have a minimum net clear opening of 5.7 square feet. Except that *grade floor openings shall have a minimum net clear opening of 5 square feet. The minimum net clear opening height dimension shall be 24". The minimum net clear opening width dimension shall be 20". The openings shall have a finished sill height not more than 44" above the floor. Emergency escape and rescue openings shall be operational from the inside of the room without use of keys or tools. Window wells shall be provided when egress windows have a finished sill height below adjacent ground elevation. The well shall allow the window to be fully opened and provide a minimum accessible net clear opening of 9 square feet, with a minimum dimension of 36". Window wells with a vertical depth of more than 44" shall be equipped with a permanent ladder. *Grade floor opening: A window or other opening located such that the sill height of the opening is not more than 44” above or below the finished ground level adjacent to the opening.
Foundation walls in finished rooms/areas shall be insulated with a minimum of R-8 insulation extending down to the basement floor slab on basement walls less than 50% above grade and a minimum of R-13 insulation on basement walls that are more than 50% above grade.
The bottom Plate of framed walls in contact with concrete must be pressure treated or naturally decay resistant wood.
Indicate size and spacing of new partition studs and finish wall material.
Approved water-resistant gypsum backer board is required in bathtub and shower areas.
Interior finish materials shall not have a flame spread rating exceeding 200.
Natural Light and Ventilation
Show all new and existing window locations and indicate the overall glass size and ventilation area for each room habitable room shall be provided with natural light not be less than 8% of floor area served. One-half of this area must be available for unobstructed ventilation with screens included. Artificial lights and/or mechanical ventilation (see ventilation section) may be used as an alternative if the existing windows are of inadequate size.. For proposed bedrooms indicate the sill height, clear opening width, and clear opening height for the required emergency escape window.
Remaining unfinished rooms/areas shall have windows with unobstructed ventilation area equal to 1% of the floor area served or artificial ventilation in the amount of .05 CFM/sq. ft. of area.
Note: Existing stairways may need to be modified with new solid risers or toe board, with possibly new replacement treads having nosings (when solid risers are provided), with new graspable handrails, and/or with new intermediate balusters for open stair guards to meet current code requirements as noted below:
- Minimum tread depth shall be 9" with solid risers. The minimum 9" tread depth is measured from the leading edge (nosing) of one tread to the leading edge (nosing) of the next adjacent tread. The Maximum riser height shall be 8.25”. The greatest riser height within any flight of stairs shall not exceed the smallest riser by more than 3/8”; the greatest tread depth within any flight of stairs shall not exceed the smallest riser by more than 3/8”.
- A continuous graspable handrail shall be provided along one side of the stair located 34" to 38" above the nosing. Handrails that form part of a guard on open-sided stairs shall also meet the guard criteria below. Handrails (and other projections below the handrail) shall not project more than 3-1/2" into the required 36" stairway width.
- Handrails shall either meet a) circular cross section with minimum diameter of 1-1/4" but not more than 2", or b) other approved shapes having a maximum allowable horizontal width of 2-1/4", maximum graspable perimeter dimension of 6-1/4", and a minimum 4" graspable perimeter dimension.
- Guards along open-sided stairs shall be a minimum of 34" in height above the leading edge of the tread and minimum of 36" in height at the stair landings. Open guards shall have intermediate vertical balusters spaced less than 4" apart. Horizontal rails, rails parallel to stair treads, and ornamental patterns that provide a ladder effect are prohibited on stairs from finished basement areas.
Glazing in doors intended for human passage, patio doors, windows within 24" of a door, and shower and bathtub enclosure walls, panels or doors, shall be fully tempered, laminated safety, approved wired glass or approved shatter-resistant plastic.
Ceiling/Floor Draft stopping
Dropped ceilings below wood joists or attached directly to wood floor trusses shall be draft stopped with ½" drywall or 3/8" plywood at 1000 sq. ft. intervals and parallel to framing members.
Fire blocking shall be provided at the ceiling line in concealed spaces of stud walls/partitions, including furred or studded-off spaces of concrete foundation walls and at soffits, dropped ceilings and similar spaces.
An AC powered, U.L. listed smoke detector with battery backup shall be located in the basement level and 1 in each sleeping room. All detectors within the house shall be interconnected so that the activation of any alarm will sound all alarms throughout the house.
Heating and Air Conditioning, Ventilation, and General Mechanical
Show location of existing furnace and main supply and return ducts. Indicate location and sizes of any new ducts, register and diffuser locations for the finished area. Detail any artificial ventilation that may be proposed for any room/space, such as for new or downsized furnace rooms, bathrooms or any finished room that does not have adequate windows for natural ventilation.
Combustion Air - Gas appliances (furnaces, water heaters, clothes dryers, etc.) located in closets or utility room spaces whose volume is less than 40 cubic feet/1000 BTU/hr. input rating shall have combustion and ventilation air provided.
Using inside air: 1 sq. in. shall be provided for each 1000 BTU/hr for each opening. Openings shall not be less than 100 sq. in. One opening shall be provided within 12" of the ceiling and within 12" above finished floor.
Using outside air:
- Horizontal openings
1 sq. in./2000 BTU/hr. for ducted opening
1 sq. in./4000 BTU/hr. for direct opening
- Vertical openings
1 sq. in./4000 BTU ducted or direct
- The minimum clearance from combustibles for appliances is 18 inches, unless the listed manufacturer's installation instructions allow an alternate clearance dimension. 18 inches of clearance is required at the front of the appliance for service.
- Clothes dryers shall be independent of all other system, and exhaust to the exterior.
- Residential bathrooms without windows for natural ventilation shall be provided with an intermittent exhaust fan at a rate of 50 CFM minimum to the exterior. It is not permissible to discharge exhaust to the attic or floor joist area.
- For finished rooms without adequate windows, outdoor air (artificial ventilation) shall be supplied at a rate of 0.35 air changes per hour or 15 cubic feet per minute per person, whichever is greater. The estimated occupant load to be used for a large common room/space such as a recreation room or a rathskeller shall be based on 2 for the first bedroom and 1 for each additional bedroom within the house.
- Gas piping shall be identified at intervals of no more than 25' when placed in concealed locations.
Show location and size of electrical panel and or sub panel (if new) and location of all new receptacles, light fixtures, ceiling fans, exhaust fans and switches or other electrical devices on the floor plans or indicate as a performance specification. Identify all 240-volt receptacles/circuits. Indicate which light and/or switches control receptacles. Any Junction boxes must remain accessible.
Ground fault circuit interrupters are required for receptacles and/or circuits installed in the following locations:
- Unfinished basement spaces except for laundry circuit and single receptacle dedicated to sump pumps.
- Receptacles to serve counter top surfaces within 6' of a wet bar.
Receptacles are required to be installed in the following areas:
- In all habitable rooms except bathrooms so that no space along a wall is more than 6' from a receptacle. All wall areas 2' wide or greater required receptacles.
- In hallways of 10' or more in length.
- In bathrooms installed adjacent to the basin.
- At least 1 receptacle in laundry area and at least one receptacle in basement unfinished area in addition to the laundry receptacle.
Lighting is required in the following areas:
- At least 1-switched lighting outlet shall be installed in every habitable room, bathroom, hallway, stairway and at exterior doors.
- Lighting installed at interior stairways shall have switches accessible at the top and bottom of each stairway without traversing any stairs, or lighting that stay on continuously or are automatically activated.
- At least 1 lighting outlet is required in each unfinished basement space or utility room that is used for storage or contains heating, air-conditioning or other equipment requiring servicing. The light switch shall be located at the point of entry.
Lighting fixtures in clothes closets:
- The use of incandescent fixtures with open or only partially enclosed lamps and the use of pendant fixtures are prohibited.
- Fixtures may be located only where there are the following minimum clearances to the nearest point of storage space.
- - Surface mounted incandescent fixtures - 12" minimum.
- - Surface mounted florescent fixtures and recessed fixtures - 6" minimum.
- Circuit breaker panels shall not be concealed and are not permitted in bathrooms or clothes closets.
- Lighting is required in the vicinity of the electrical panel.
- A minimum of 3' clearance is required in front of existing electrical panels.
Show location of any new plumbing fixture such as bar sink(s), lavatories, water closets, bathtubs, showers, hot water heater(s), floor drain(s) and other plumbing fixtures on the floor plans. Show location of plumbing chases. Show the location of new washer hose connection bibs and laundry standpipe in new laundry rooms/space.
Note: The preceding requirements apply to most simple residential basement finishing projects. However, the Plan Reviewer may determine that unusual circumstances dictate the need for additional information on any particular project. It should also be emphasized that especially on interior renovation projects many Code requirements are verified through the inspection process and are not necessarily reflected within the approve plan documents.
The minimum permit fee is $51.00 for each required permit (building, plumbing, electrical and mechanical)
If you should have any questions Please call the Department of Building Inspections at (703)-335-8815 Monday through Friday from 8:30 AM to 5:00 P.M.
Minimum Inspection Requirements
- Plumbing, Electrical or Mechanical Ground works Inspection-prior to cover or backfilling trenches or openings
- Framing Inspection-prior to placement of any insulating material or wall covering
- Electrical close in-Inspection-prior to placement of any insulating material or wall coverings
- Mechanical close-in Inspection-prior to placement of any insulating material or wall coverings
- Plumbing close in Inspection-prior to placement of any insulating material or wall coverings
- Final inspection upon completion of all work