FAQ

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 and humidity.  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 cure because they are applied at a heavier rate than spray or brush grade coatings.

When flashing cement cures it will continue to have a "putty-like" consistency.  This is the nature of roofing asphalt and is advantageous because it allows the repair sealant to expand and contract with the roof substrate."  The curing process will continue depending on the thickness of the applied material and may take several weeks or longer.  This process, as well, depending on the ambient temperature, may be longer or shorter.

Once applied, the either the KARNAK #19 or #19 Ultra or#155 will perform as designed throughout the "Skinning Over"/"Curing" process.  Depending on the application, expansion/contraction movement and nature of repair, the flashing cement can perform for upward of several years or longer.  This time frame can vary either longer or shorter.

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

Most KARNAK products should not be applied if rain is imminent within 24 hours.  The exception to this is KARNAK’s 155Amphibikote or 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. 502MSKarna-Flex may also be applied to applicable wet roof surfaces as an emergency repair sealant.

How soon after it rains can KARNAK products be applied?

24 to 48 hours, if surface is fully dry.

What temperatures can KARNAK products be applied at?

The recommended application temperature for most all coatings and sealants is 40°F and rising.  See individual product data sheets for recommended application temperature. The exception to this are aluminum coatings, which should be applied at 50°F and rising.

Asphalt flashing cements and thermoplastic sealants may be applied below 40°F but understand the application may be difficult due to the increase in viscosity that occurs when the product’s temperature is lowered.  The application of products at or below freezing temperatures could result in adhesive failure unless special precautions are taken to ensure the surface is free of moisture or ice crystals.  

Do reflective roof coatings stop leaks?

No, reflective roof coatings help protect the roof in the condition it is in at the time of coating application.  Reflective roof coatings protect the underlying roof from direct UV exposure thereby helping prolong roof life.  They also reduce roof surface temperatures which can reduce heat transfer into the structure.  If a roof is leaking, the leaks needs to be stopped by either repairing with like material or using one of KARNAK’s appropriate flashing cements or sealants. Once all roof leaks are stopped then an appropriate coating may be applied.

How many different roof coating options does KARNAK offer?

Not all roofs are the same so KARNAK offers a number of roof coating options based on roof substrate, budget and desired results:

·       Asphalt

·       Elastomeric Asphalt

·       Aluminum

·       Elastomeric Aluminum

·       Acrylic

·       Thermoplastic Rubber

·       Silicone

Contact KARNAK Technical Services at 800-526-4236 to hear what options are available for your roof.

Does KARNAK offer Warranties on roofing products?

YES! Please check out the Warranty tab or contact KARNAK for warranty information.

Where can I obtain KARNAK products?

KARNAK products are available through a variety of distributors in the U.S. and overseas. Please contact KARNAK Customer Service for your nearest distributor: Phone 800-526-4236 or email info@KARNAKcorp.com.

What factors can affect the life expectancy of reflective coatings?

·       Improper drainage: Improper drainage can cause water to accumulate on the roof (Ponding) and may lead to delamination of the coating.  Silicone coatings are the exception as they perform well in ponding conditions.

·       Surface preparation: Poor or improper preparation of the substrate surface may still leave contaminates behind, which can affect the adhesion of roof coatings to the surface.

·       Material application: Inadequate coverage rates can result in the coating failing prematurely.

·       Traffic: Heavy roof surface traffic can shorten the life expectancy of the coating.

·       Weather severity: depending on the geographical location of the building, weather conditions, such as, freeze / thaw and constant rain can affect the 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.  These can adversely affect the coating and reduce reflectivity.

·       Improper mixing: Mixing should be used to ensure that a coating is homogenous.  It’s especially important for aluminum coatings as the aluminum pigment settles out during storage and shipment.  If coatings are not mixed to an even consistency, there may be streaking during application and the finish coating will not be as even and reflective as intended.  Coatings 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.

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, roof assembly must be tested with Underwriters Labs.  Please consult the UL roofing and material system directory or contact KARNAK Technical Services at 800-526-4236.

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.  The only exception to this is 180 Karna-Sil Epoxy Primer which may be thinned with water. Check the product data sheet for thinning instructions.  

How soon can I coat an installed torch-applied 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.

What effect does ponding water have on reflective roof coatings?

Reflective roof coatings in general do not perform well on roofs that pond water.  Dirt can accumulate in depressions and inhibit the reflectance of the coating.  If an aluminum or acrylic coating is underwater 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 coating intact.  Silicone coatings exhibit excellent resistance to ponding water making them a good choice for roofs subject to these conditions.

Should primers be used with aluminum coatings?

If a “primer” is needed over an asphalt built-up (BUR) roof, smooth or granular modified bitumen membrane or granule cap sheet, one of KARNAK’s asphalt emulsion coatings (100 Non-Fibered Emulsion Roof Coating or 220 Fibered Emulsion Roof Coating) may be applied to provide a firm base on which to apply the KARNAK aluminum coating 7 to 10 days after the emulsion coating has cured.

How can I be sure if a coating will adhere to a Single-Ply (TPO/PVC/Hypalon) or previously coated roof?

An adhesion test is the best way to determine if a coating will adhere. Contact your KARNAK Regional Sales Manager to set up an adhesion test and discuss the application.

Can I use your asphalt/tar remove on cars or siding?

KARNAK 709 Karna-Klean is a biodegradable, petroleum free and chlorinated solvent free cleaner/degreaser with all natural ingredients. The base ingredient in this highly concentrated formulation is a natural solvent obtained from orange peel and pulp. KARNAK 709 Karna-Klean dissolves and removes asphalt, tar, grease, grime, and asphalt emulsions. Cleans asphalt and tar from brick, cement, stucco, concrete, metal and all types of roofing equipment. Also cleans and removes ink, adhesives, oil residues and most paints, graphite, dirt and scale.

NOTE: 709 Karna-Klean is a solvent. As a result, some staining may occur. Pretest on all plastic or other questionable surfaces prior to use.

How do I apply your products?

Application of KARNAK products, ​depending on which product, i.e., "Brush Grade", "Trowel Grade" or "Spray Grade" is used, can be applied be either Trowel, Brush, Roller, Squeegee or Spray Equipment.

Can I use your products to coat over my old shingle roof?

Most shingles are not designed to handle any type of protective coating, in fact the National Roofing Contractors Association (NRCA)does not recommend any type of protective coating be applied to shingle roofs, especially in warm parts of the country, such as Florida as well as in Northern U.S. states.

Additionally, state and/or local building codes should be checked since field applied coatings may change the performance characteristics of the roof, including but not limited to fire classification, of the roof.  Some of the problems encountered after asphalt shingle roofs have been coated include but not limited to shrinkage of the coating, which may result in curling and/or cupping of the shingles, loosening of the shingles granule surfacing. Also, application of a non-permeable roof coatings may create a vapor retarding layer that can increases the potential for rotting of the roof deck caused by moisture accumulation in the attic space.

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