DFE-1 (NLB). CSI 3-Part Specifications.

Base Flashing

For non load-bearing construction, using roof-to-wall expansion joint cover

General

This flashing specification is for use on non load-bearing construction, or where there is any potential for differential movement between the deck and the wall or parapet. The vertical wood curb should be fastened to the deck only.

Note: All general instructions contained in the current JM Commercial/Industrial Roofing Systems Manual shall be considered part of this specification.

Wall Preparation: Any previously installed metal cap or counterflashing must be lifted or removed, to permit application of the expansion joint cover.

Materials

Base Flashing and Expand-O-Flash: Approximately 100 lineal feet (30.5 lineal meters) of base flashing (8" [203 mm] high above the roof) and Expand-O-Flash can be installed with the following materials. Usage will vary depending on actual flashing height and field conditions.

Application

Base Flashing: The roofing membrane must extend to the top of the cant. The completed base flashing shall extend not less than 8" (203 mm) above the level of the roof, and shall extend onto the roof membrane a minimum of 4" (102 mm). Cut the DynaFlex into sections that can be easily handled and installed (6' - 8' [1.83 m - 2.44 m] long), and position upside down on the membrane, to allow the product to relax.

Hot Asphalt Application: Starting just above the point on the curb where the base flashing will terminate, mop the curb, the surface of the roofing felts on the cant, and out onto the roof membrane with hot Type III* or IV asphalt. Holding the upper corners of the DynaFlex, position its lower horizontal edge on the roof membrane (minimum 4" [102 mm] from base of cant) and lay it into place over the cant strip and up the curb. The sheet should be "worked-in" to ensure that it is firmly and uniformly bonded. The asphalt temperature shall be a minimum of 400�F (204�C) or at the EVT, whichever is higher, when the DynaFlex is set into it. This higher temperature maximizes the bonding of the base flashing. In cool or cold weather, the back of the DynaFlex sheet should also be mopped with the hot asphalt, and shorter lengths of DynaFlex should be used. PermaMop may not be used to install DynaFlex.

Cold Adhesive Application: Starting just above the point on the curb where the base flashing will terminate, coat the curb, the surface of the roofing felts on the cant, and out onto the roof membrane with a layer of MBR Flashing Cement approximately 1/16" (1.6 mm) thick, or a layer of MBR Utility Cement approximately 1/8" (3 mm) thick. Holding the upper corners of the DynaFlex, position its lower horizontal edge on the roof membrane (minimum 4" [102 mm] from base of cant) and lay it into place over the cant strip and up the curb. The sheet should be "worked-in" to ensure that it is firmly and uniformly bonded.

In both hot and cold applications, the vertical joints are to be overlapped a minimum of 4" (102 mm) and well sealed. Mechanically fasten the base flashing on 6" (152 mm) centers along its top edge. Fasteners must have a 1" (25 mm) minimum diameter integral cap, or be driven through 1" (25 mm) minimum diameter rigid metal discs. It is recommended that the vertical laps be covered with a 1 �8" (3 mm) thick layer of MBR Flashing Cement, or a 4" (102 mm) wide strip of fiber glass mesh or ply felt embedded in and trowelled over with a layer of MBR Utility Cement.

Expand-O-Flash Installation: Install Expand-O-Flash in accordance with the application instructions included with the product. Prefabricated inside and outside corners, as well as horizontal-to-vertical transitions, are available to complete the Expand-O-Flash installation.

Metal Counterflashing: The metal counterflashing of the wall flange should be installed in accordance with the counterflashing manufacturer’s specifications and details, or in accordance with SMACNA procedures.

Surfacing: DynaFlex requires no additional surfacing.

* Consult a JM Technical Services Specialist regarding the use of Type III asphalt in hot climates.

 

For an identical copy of this specification, ask for RS-4218.