General
Flashings are the terminal closures of a roofing system which perform a waterproofing, and, in some systems, a decorative function. Flashings must be installed at all intersections formed by vertical surfaces. Water entering the roofing system through flashings will destroy the effectiveness of the roofing.

Koppers flashings are an integral part of a Koppers roof. Designed for flexibility so that slight movements do not dislodge them and fastened securely to the wall, they give many years of service.

It is particularly important that the top edge of the flashing be protected by a three course application of Koppers Cold Applied Polyester or Asphalt Glasfab embedded and covered with Koppers Flash-On 441 or Koppers ONYX Modified Flashing Cement and then counterflashing installed which will assure a diversion of the water away from any opening which may develop between flashing and wall.

Metalwork is only useful for decoration, water shedding, or protection against mechanical damage, and is not a waterproofing part of the flashing system.

Flashing should be installed as roofing progresses to prevent water damage to insulation or deck under the roofing. If this is not possible, water stops must be installed and completely removed prior to continuation. Metal counterflashing must be installed as flashing progresses.

The basic Koppers flashings require the use of metal counterflashing. When using throughwall counterflashing, it is recommended that the designer specify two piece counterflashing to facilitate ease of flashing installation, maintenance and repair.

Metal counterflashing is to have not less than a four (4) inch (102mm) exposed apron extending down over the base flashing.

NOTE:
  1. If warranted flashing is required, it must be installed in conjunction with a Koppers warranted roof and can be warranted for up to but not greater than the period for which the roofing is warranted. To be warranted, flashing must be set at least 8" (203mm) above the roofing base.
  2. The maximum warranty period for flashings are as follows:
    1. 10 years: Nos. 172 & 174
    2. 20 years: Nos. 176, 180, & 182.
  3. Metal counterflashings are not included under any flashing warranty.
  4. Metalwork of any description used as flashing or a part of a flashing system is not included under any flashing warranty.
  5. Care should be taken not to cover weep holes.
  6. Koppers requires the use of an anchor bar (1/8" thick) (3 mm) system for fastening the top edge of vertical flashing systems. If wood nailers are provided, nailing through the top edge of the flashing system on eight (8) inch (203mm) centers using 1" diameter cap nails is an acceptable alternate in lieu of anchor bars. Sealing the top edge is required.
  7. Recommended application rates as provided in each of the following specifications are to be used as guides. Actual application rates will depend upon substrate surface, weather conditions, and other factors at the job site.
  8. It is recommended that all curb, wall, projection and reentry corners be reinforced by applying a layer of Hot Polyester membrane (gray color) or woven glass fabric in an application of the specified roofing bitumen, over the completed membrane but before aggregate or coating surfacing. Apply a full width sheet around the roof top opening out from the base of the flashing, overlapping the corners and from wall reentry corners 8' (2.4m) down each side overlapping the corner.
  9. Koppers requires that flashings be inspected periodically and repaired as necessary. Koppers requires that smooth surface flashings be recoated with aluminum roof coating at least every five years.
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