Attic Draftstopping Detail

The space between the ceiling beams of the top story and the roof rafters.

Attic draftstopping detail.

Draftstopping is used to subdivide flooring at specific intervals and in attics and crawl spaces. This self closing and self latching access door allows for access from both sides of the door. 2 if the assembly isn t concealed an open floor ceiling assembly above a basement draftstoppingisn t required. Where the assembly is enclosed by a floor membrane above and a ceiling membrane below draftstopping shall be provided in floor ceiling assemblies under the following circumstances.

Click to view a larger image draft stop access door the babcock davis draft stop door is a non rated access door designed to provide access through draft stop spaces in the attic while preventing a back draft from one section of the attic to another. O draftstopping must be installed to subdivide concealed combustible attic spaces into areas not exceeding 3 000 sq ft or above every two dwelling units whichever is smaller where a corridor also serves as a dwelling unit separation draftstopping is only required above one of the corridor walls. In combustible construction nearly all the codes specify that lumber or wood structural panels may be used for this purpose. Draftstopping shall divide the concealed space into approximately equal areas.

A horizontal area of 1 000 ft sq between draftstops is a typical requirement in non residential buildings in floors. There are some points to be made about the draftstoppingrequirements. Draftstopping is usually provided by requiring a plywood or gypsum board barrier at 3 000 ft sq intervals in attic spaces. In combustible construction draftstopping shall be installed to subdivide attic spaces and concealed roof spaces in the locations prescribed in sections 718 4 2 and 718 4 3.

If there is no useable space above the assembly an attic or below it a crawlspace draftstopping isn t required. 3 if draftstoppingis required the 1 000 sflimit applies but the divided spaces must be approximately equal. 718 4 draftstopping in attics. Multi unit housing projects are often draftstopped at specific intervals to prevent fire from jumping between adjacent units via a common attic space.

Similar to fireblocking draftstopping is installed to prevent the movement of air within open building areas and is most often installed in crawl spaces attics and floor assemblies. Ceiling is suspended under the floor framing. Ventilation of concealed roof spaces shall be maintained in accordance with section 1203 2. Some codes include other draftstopping materials such as gypsum board cement fiber board or particleboard.

If draftstopping is required the 1 000 sf limit applies but the divided spaces must be approximately. In combustible construction draftstopping shall be installed to subdivide attic spaces and concealed roof spaces in the locations prescribed in sections 718 4 2 and 718 4 3.