vent extension

vent extension

A pipe from the uppermost drainage branch connection through the roof to the atmosphere.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
To release the underlap, clip the left seam allowance to the dot, then press under the serging on the left vent extension and edgestitch (7).
Press the vent extension on top of the right vent extension, creating the underlap.