DFE-18 (LB). CSI 3-Part Specifications.

	BITUMINOUS FLASHINGS
	Specification DFE-18 (LB)

DynaClad Base Flashing for Load-Bearing Masonry Construction

General

This flashing specification is for use on masonry parapets that can accept and retain the required mechanical fasteners, and where the roof deck is supported by the parapet.

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 base flashing.

Apply JM Concrete Primer to the masonry wall, to the full height of the proposed base flashing and counterflashing, and allow the primer to dry thoroughly.

Materials

Base Flashing: Approximately 100 lineal feet (30.5 lineal meters) of base flashing (8" [203 mm] high above the roof) 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) nor more than 28" (71.1 m) above the level of the roof, and shall extend onto the roof membrane a minimum of 6" (102 mm). DynaBase is installed as a backer felt in hot Type III* or Type IV asphalt. The bottom edge of the DynaBase should terminate at the bottom edge (base) of the cant. The top of the DynaBase should be nailed 9" (229 mm) o.c. across the top of the sheet.

Cut the DynaClad into sections that can be easily handled and installed, and position on the membrane.

Heat Weld Application: Using a propane torch, apply the flame to the surface of the roll until the surface reaches the proper application temperature (approx. 330�F [166�C]). The flame should be moved from side to side and the DynaClad slowly rolled into place while pressing it onto the underlying surface. As the surface of the roll is heated, the polyolefin film will melt and the SBS modified bitumen compound will develop a sheen. The generation of smoke is an indication that the material is being overheated.

Subsequent pieces of DynaClad should be installed in the same manner, making sure to heat the exposed selvage edge (see below) of the previously applied sheet. Maintain min. 4" (102 mm) side laps.

Seam Applications: Lightly heat the top metal surface of the flashing at the 4" (102 mm) lap and gently score the surface with a knife in a straight line. Remove the 4" (102 mm) of metal surfacing, creating the selvage edge. Next, apply heat to the lap that is being seamed, making sure there is a good compound flow to adhere the two surfaces. Check all laps for good adhesion.

As an alternate method, the metal surface to be seamed can be primed with JM Metal Primer. Prime the metal surface, letting it set until thoroughly dry. Next, apply heat to the overlapping sheet and install it to the dry primed surface making sure it adheres well to the metal surface. Check all laps for good adhesion.

The installed DynaClad must be nailed across the top edge 6" (152 mm) o.c. Use a damp burlap to cover and protect the exposed metal surface from excessive flame of the torch. Use a wet soapy sponge or wool rag to rub/press the material to assure the sheet conforms to the substrate and at flashing seams. Crimp all cut or exposed metal edges into the hot modified compound flow. Cut and remove all voids in the metal surfacing and repair with an additional piece of DynaClad.

For heat weld application, all safety procedures must be reviewed prior to application. All contractors must understand, review and adhere to the information contained in the following sources:

Metal Coping: Metal coping should be installed in accordance with the coping manufacturer’s specifications and details, or in accordance with SMACNA procedures.

Surfacing: DynaClad requires no additional surfacing.

For an identical copy of this specification, ask for RS-4230.