Specification & Codes
Restoration of Graveled Roof Areas
All preliminary steps for restoration are to be done, as specified, prior to the application of Karnak's P-21 System.
- Remove all loose aggregate as well as all dirt, dust and other foreign material from the roof surface. This may be done by power vacuum, brooming, high pressure air or water or any combination that assures a clean surface.
Note: If water is used, caution should be exercised to assure the water does not enter the insulation or decking through surface breaks in the roof mat. Caution should also be exercised so the amount of air or water pressure used does not damage the roof surface.
- Trim all raised and/or standing seams flush with the roof mat and, if necessary, restore or reinforce as necessary.
- Apply Karnak #108 Primer at a rate of 1 to 2 gallons per 100 square feet extending the primer a few feet beyond the area that will receive coating (this should seal all loose dirt below the gravel surface and block moisture penetration from the sides).
DRAINS AND PROJECTIONS
- Spud and scrape off the remaining gravel to as smooth a surface as possible around each drain or projection, approximately to the flashing-shield line. Care should be taken not to damage the roofing felts.
- Thoroughly clean the area free of all dust and dirt.
- Apply Karnak #108 Asphalt Primer at a rate of 1 to 2 gallons per 100 square feet, covering all surfaces that will receive flashing cement or coating.
- Apply Karnak #19 or #19AF Flashing Cement at the rate of 4 to 6 gallons per 100 square feet (on drains, up to the flange but being careful not to cover weep holes).
- Embed Karnak #31 Fiberglass Membrane into the freshly applied Flashing Cement, smoothing out any voids, wrinkles or fishmouths.
- Apply a second coat over the mat with Karnak No. 19 Flashing Cement.
- Apply Karnak #78AF Cold Process Cement at a rate of 6 gallons per 100 square feet.
- Embed Karnak #5540 Resat-Mat into the wet coating carefully pressing the mat into the coating to displace all trapped air.
- Apply a second coat of Karnak #78AF Cold Process Cement at a rate of 4-5 gallons per 100 square feet.