The surface to which SOMAY ROOF MASTIC® is to be applied MUST be thoroughly clean and completely free of anything which could adversely affect the adhesion of the coating to the surface, including:  all previous coatings which are glossy, loose, scaling, chipping, flaking, blistering, powdering, peeling or chalking;  all dust, dirt, soot, sand, gravel, grease, oil, uncured or infirm tar, curing agents, parting compounds, wax, soap film, rust, oxidation or petroleum-

based residue;  lye, lime, chlorine, salt or salt film, calcimine, efflorescence, or any other chemically reactive substance;  and MUST be free of all mold, mildew, fungus and other growing organism.  Infirm surfaces MUST be made firm.

Cleaning

A high pressure (min. 2,500 P.S.I. at the tip) water blast should be used to thoroughly clean all surfaces prior to the application of a coating.  Mildew and similar growths MUST be killed with, for example, a 2%-3% chlorine solution  in water (e.g. "Clorox" diluted 1:1 with water), followed by a thorough rinse with clean water. Note:  Protect landscaping from chlorine runoff. Note:  Use caution if/and when cleaning a shingle, tar paper, roll roofing or similar fragile roof surface, so as not to damage the roof surface.

Dry the Surface:

Allow clean surfaces to dry thoroughly.  If the surface to be coated is wet or damp, wait for it to dry or accelerate the drying by using a fan or a blower from a hair dryer or the exhaust from a vacuum cleaner.

Prime All Porous Surfaces:

Following proper surface preparation, all porous surfaces such as Asphalt Shingles, Asbestos Shingles, Fiberglass Shingles, Composition Shingles, Asphalt Roll Roofing, 90 Pound "Slate", Tar Paper, Concrete, Flat Tiles, Barrel Tiles, etc. should be primed with undiluted SOMAY Product No. 777, SOMAY "PST", Primer, Sealer, Topcoat (Clear), prior to caulking or the application of the first coat of SOMAY "ROOF MASTIC".  Apply Primer using a one (1) gallon (3.79 L) to cover a maximum of 275 sq.ft. (25.54 sq.m.) of roof surface,  to seal the pores in the shingles, tiles, etc.  On very porous surfaces, such as old, dried out asphalt shingles, the spreading rate may be significantly reduced to perhaps only 80 to 100 sq.ft./gallon.  Allow to dry thoroughly.

NOTE: If applying "ROOF MASTIC" to shingles that are old, brittle or curling, prior to the application of No. 777 "PST" Primer and No. 842, SOMAY "ROOF MASTIC", apply one coat of SOMAY Product No. 789, SOMAY "SHINGLE PREP", which is formulated to soften old shingles so that they will be flexible and will lie flat on the surface. SOMAY "SHINGLE PREP" is applied at a maximum rate of 200 sq.ft. gal. but is designed to be absorbed by the shingles, not to build any film thickness on top of the shingles.

SOMAY "ROOF MASTIC" should not be applied directly over a steel (ferrous metal) surface unless the steel has been previously primed, painted or "galvanized".

Prior to the application of SOMAY "ROOF MASTIC", do NOT use a rust "Reformer", a rust "Converter", a rust "phosphatizing" solution or similar process over the rusty areas of a steel surface. These are usually acidic products, which will be incompatible with any acrylic coating.  SOMAY "ROOF MASTIC" is a 100% acrylic resin-based coating, because acrylic resins are the most resistant to degradation from the ultraviolet rays from sunlight.  However, acrylic coatings should be applied to surfaces that are neutral to slightly alkaline, but not over an acid contaminated surface.

Therefore, when applying SOMAY "ROOF MASTIC" to older, deteriorating, previously painted or galvanized, flat or corrugated steel (ferrous metal) panels that are partially or lightly rusted, we recommend:

Surface Preparation:

The loose, flaking, or chipping rust MUST be removed by hand cleaning such as scraping or wire brushing to be sure there is a firm surface on which to apply SOMAY "ROOF MASTIC" .  It is NOT necessary to remove rust which is firmly or soundly adherent to the steel substrate.

Primer:

(A)  Then "spot" prime the rusty areas with SOMAY/Carboline "Rustbond", a Clear, 100% Solids, 2-component, 1:1 mix ratio, polyamido amine epoxy containing corrosion inhibitors, which serves as a universal primer/tie-coat.  Coverage is 786 sq. ft. per gallon (or 19.26 sq.m./3.79L), at 2 mils (50 microns) dry film thickness; or

(B) Prime the bare, rust-free areas with SOMAY Product No. 636, Ferrous Metal Primer meeting U. S. Federal Government Specification TT-P-636; coverage will be approximately 300 sq.ft./gal. (27.87 sq.m./ 3.79L) at 2 mils (50 microns) dry film thickness.

Either of these coatings can be topcoated when dry, normally in approx. 12 hours @ 75 F. 

SOMAY "ROOF MASTIC" can be applied directly to clean, weathered, galvanized steel surfaces, or to primed or previously painted steel surfaces, and directly over a ferrous metal coating as in (A) and (B) above that is dry and cured.

Repair Cracks, Open Seams, etc.

It is more efficient and economical to develop a seamless waterproofing membrane with SOMAY "ROOF MASTIC" when it is applied to surfaces which are very smooth.  Therefore, all large, open seams, cracks, holes and similar irregularities should be filled and made very smooth using SOMAY Product No. 992, SOMAY Elastomeric "PATCH & SEAL".

NOTE:  It is NOT necessary to completely fill in the cut-outs between the tabs of shingles, if you wish the appearance of the shingle tabs to show through the SOMAY "ROOF MASTIC".  However, all cracks, tears, holes, etc. must be filled.

For a more economical job, it is recommended that the vertical joints between flat cement tiles be filled with SOMAY Product No. 992, "PATCH & SEAL", to make a smooth surface for the SOMAY "ROOF MASTIC".

SOMAY "PATCH & SEAL" must be applied full strength as it comes from the can.  However, if you wish to reduce the viscosity of the SOMAY "PATCH & SEAL", to make it easier to apply, you can mix in a little SOMAY "ROOF MASTIC", Product No. 842, which is made from the same resin system and therefore will be completely compatible.  NEVER THIN, DILUTE OR ADULTERATE with any other material.

Apply SOMAY "PATCH & SEAL" with a brush, putty knife, or similar tool.  SOMAY" PATCH & SEAL" should be worked into all pores, cracks and seams so they are sufficiently filled to leave a smooth finish with the adjacent surfaces.

NEVER use concrete or other substitutes.