Flashing Policy


  • Flashing material will be three(3) ounce copper coated flexible material of proper width to turn up two(2) inches behind wall board or two(2) inches into block back-up – down back-up no less than eight(8) inches through cavity, completely through face and left visible. If wallboard or back-up wall is already in place we require use of a termination bar and cut off mastic.
  • Flashing between two(2) masonry materials will be bedded on a thin bed of mortar with a thin bed of mortar on top – all laps installed with mastic and any penetrations patched with mastic. Mastic will be as recommended by flashing manufacturer.
  • Flashing termination in masonry will be end dammed. Corners will be carefully lapped, fitted, and sealed as recommended by flashing manufacturer.
  • Weep holes will be cotton sash cord rope penetrating the face, turned up 16 inches, and attached to back-up. Cavities filled two(2) inches high with river pea gravel – Keep cavities relatively clean – with no extruded mortar blocking the cavity.
  • Under all shelf angles, a thin soft joint material will be installed and joints will be left free of mortar for caulking under flashing turned out. At all expansions joints and control joints, joint is to be totally free from bridging mortar.
  • Flashing will be used under all free-standing wall copings or rowlock caps.
  • Head and bed joints will be filled. Pin holes will be pointed as work progresses.
  • Tops of masonry walls will be covered daily.
  • Scaffold boards adjacent to exposed masonry walls will be swept or removed at end of each day.

Our policy intends to comply with BIA Technical Note #7 – Water Resistance of Brick Masonry Design and Detailing, and NCMA Technical Note #19 Series.

This policy is WASCO, Inc.’s preferred method of installation and preferred product types. We will use other types of flashing when specified, but strongly encourage no usage of PVC flashings. The weep hole rope is our recommendation based upon experience. We will install alternative materials but strongly discourage tubes. Pea gravel is our recommended method of protecting the cavity and flashing base but other specified materials are acceptable. Cavity vents at tops of walls, in our opinion, improve the breathability of the cavity preventing condensation buildup.