Roofing FAQs

1. Does KARNAK offer Warranties or Guarantees on Roofing products?

YES! Please contact KARNAK Corporation for Warranty information.

2. Does KARNAK offer an approved roofers program?

KARNAK realizes that from time to time the need arises for KARNAK materials to be applied by an approved applicator. KARNAK does recognize the ability of applicators that install KARNAK products if they have been doing such installations for at least three (3) years. This is with the understanding that the KARNAK materials are installed in accordance with KARNAK’s specifications.

3. Where can I obtain KARNAK products?

KARNAK products are available through a variety of distributors in the U.S. and overseas. Please contact KARNAK for your nearest distributor: Phone 1-800-526-4236, 1-732-388-0300, Fax 1-732-388-9422 or email KARNAK

4. What is the dry or cure time for KARNAK products?

The dry or cure time for KARNAK products depends on the specific product used and the outside ambient temperature. For the most part, KARNAK brush or spray grade coatings will dry in 24 hours. KARNAK flashing cements and mastics, will “skin” over in 24 hours, but take longer to fully dry because they are applied at a heavier rate than spray or brush grade coatings.

5. Can I apply KARNAK coatings or cements if rain is imminent?

KARNAK products should not be applied if rain is imminent within 24 hours. The exception to this is KARNAK’s #155, #155AF Amphikote and #19 Ultra Rubberized Flashing Cement, these products are designed to be used in either wet or dry conditions, thereby making them ideal for use as emergency repair situations.

6. How soon after it rains can KARNAK products be applied?

24 to 48 hours, if surface is fully dry.

7. How do I clean up a spilled KARNAK product?

Consult MSDS on the specific product

8. Why should I use an aluminum coating to coat my roof?

Aluminum coatings can form an invaluable part of a smooth surface built-up roof (BUR), smooth or mineral surface modified roofs (SBS) or torch-down (APP) roofing systems. Aluminum coatings form a highly reflective surface that reduces roof surface temperatures (approximately 15 to 20(F), which can equate in lower internal temperatures. Aluminum coatings also protect the underlying membrane (BUR, SBS, or APP) from UV degradation, thereby helping prolong its life.

In brief, Aluminum coatings:

  • Extend the life of the roof system.
  • Reduce roof surface temperatures.
  • Reduce thermal shock and stress to the roof.
  • Make leaks easier to identify.
  • Help the environment by reflecting heat and reducing temperature.
  • Provide fire protection (See UL Class A Fire Ratings)

9. What is the life expectancy of KARNAK's Aluminum roof coatings?

Normally, aluminum roof coatings have a service life of between 3 to 7 years, depending on the surface coated and other factors.

10. What factors can affect the reflectivity and life expectancy of aluminum coatings?

Factors that affect reflectivity and life expectancy of aluminum coatings are:

  • Improper drainage: Improper drainage can cause water to accumulate on the roof (Ponding) and may lead to delamination of the aluminum coating.
  • Surface preparation: Poor or improper preparation of the substrate surface may still leave contaminates behind, which can affect the adhesion of the aluminum coating to the surface.
  • Material application: Inadequate coverage rates or over working the aluminum coating can result in the aluminum coating improperly leafing out and failing prematurely. Also, multi-directional rolling or brushing can lead to poor aesthetics of the dried aluminum coating.
  • Traffic: Heavy roof surface traffic can shorten the life expectancy of the aluminum coating.
  • Weather severity: depending on the geographical location of the building, weather conditions, such as, freeze / thaw and constant rain can affect the aluminum coating.
  • Surface contamination: Surface contaminates which can accumulate on the roof surface may consist of broad a range of pollutants. They include, but are not limited to dust, dirt, oils, animal fats, greases, pollen, acids, alkalis, solvents and other chemicals either as fine particles or liquids.
  • Improper mixing: Aluminum pigment tends to settle out during storage and shipment. Mixing should be used to ensure that all the aluminum pigment is evenly dispersed. If dispersion is not complete, there may be streaking during application. Aluminum pigment left in the bottom of the pail will result in the aluminum coating not being as reflective as desired. Product should be applied immediately after mixing or additional mixing will be required.
  • Ponding water: Ponding water is the accumulation of water that remains on the roof surface 24 to 48 hours or longer.

11. What should I use to mix KARNAK's aluminum coatings?

Mechanical mixer, such as a 1/2″ drill with a double bladed – paddle mixer or similar device can be used: (i.e.: Jiffy Mixer).

12. How do I obtain a UL fire Rating for my roof?

If the roof system you have is classified with KARNAK, coating it according to U.L.’s specifications for KARNAK listed products, will give the roof a UL Class A Rating. One common misconception is that when any roof is coated with a UL labeled material, the roof automatically achieves a UL fire rating. This is not true. In order to achieve a UL fire rating, the entire roof assembly must be tested with Underwriters Labs. Please consult the UL roofing and material system directory (Click Here for KARNAK UL Listing).

13. Is there a listing of KARNAK UL and FM rated products and systems?

14. Can KARNAK products be thinned and if so, with what type of thinner?

KARNAK products should not be altered or thinned. Any attempts at thinning the products can alter their designed physical properties, thereby resulting in possible product failure and/or shorten longevity of the cured material. Thinning of solvent base products is in direct violation of V.O.C. (Volatile Organic Compound) laws and regulations.

15. How soon can I coat a installed APP Modified Bitumen roof membrane?

KARNAK recommends coating new modified bitumen (APP) membranes as soon as possible after the membrane has been installed. If more than 30 days, follow RCMA/ARMA Field Surface Evaluation Guidelines.

16. What effect does ponded water have on aluminum coatings?

Aluminum coatings do not perform well on roofs that pond water. Dirt can accumulate in depressions and inhibit the reflectance of the coating. If an aluminum coating is under water for a prolonged period of time, the water may work its way under the coating causing it to lift and peel up. Positive drainage is necessary to flush away any accumulation of surface dirt from the roof and keep the reflective properties of the aluminum coating intact.

17. How soon can I coat a newly installed built-up roof with an aluminum roof coating?

New asphalt built-up roof (BUR) surfaces, should weather a minimum of 90 to 180 days, prior to coating with a KARNAK’s aluminum roof coating’s (i.e.: #27AF, #28AF, #97, #97AF, #169AF and #298 Alumin-r).

18. Can new built-up roofing (BUR) systems be coated with aluminum coatings sooner than the recommended 90 to 180 days weathering period?

If an aluminum surface coating must be applied sooner to a new built-up roof, an emulsion (water base) coating should be used instead of an asphalt flood coat. An emulsion coating, such as KARNAK’s #220AF Emulsion Coating, will provide a firm base on which to apply the KARNAK aluminum coating 5 to 10 days after the emulsion has cured.

19. Should primers be used with aluminum coatings?

Cutback asphalt primers can act as an asphalt glaze coating and bleed through the aluminum coating unless the primer is allowed to weather 90 to 180 days.