SOMAY PRODUCTS, INC.
4301 NW 35TH AVENUE
MIAMI, FLORIDA 33142-4382, USA
Tel: 305-633-6333 Fax: 305-638-5524
Toll Free: 888-2-4-SOMAY
e-mail: paint@somay.com URL: http://www.somay.com
Since 1926 – Manufacturer of Decorative and Protective Paints and Waterproofing Coatings
PROPER SURFACE PREPARATION PRIOR TO
Coating with the SOMAY “ROOF MASTIC” System
(Pigmented - White & Stock Colors)
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
organisms. 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. Be sure to protect landscaping from chlorine runoff. Use
caution 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:
On concrete or tile surfaces, apply SOMAY Product No. 777, SOMAY “PST”, Primer, Sealer,
Topcoat (Clear), prior to caulking or the application of the first coat of Pigmented or Colored
SOMAY “ROOF MASTIC”. On asphalt-based roof surfaces in good condition, such as asphalt
or fiberglass shingles, roll roofing, tarpaper, etc., apply SOMAY Product No. 7751, SOMAY
“PRIME & SEAL”. Maximum spreading rate of primers is 200 sq.ft./gal., but may be
considerably less (maybe only 100 sq.ft./gallon) on old, dried out shingles. Allow to dry
thoroughly.
NOTE: When applying SOMAY "ROOF MASTIC" Sealer & Protector in “CLEAR” (NonPigmented), NO primer is used.
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NOTE: If applying any paint or coating to asphalt shingles that are old, brittle or curling, 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.
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 “PATCH & SEAL”. Since “PATCH & SEAL” is
White in color, it should not be used on any surface where a Crystal Clear finish is desired.
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
or barrel tiles be filled with SOMAY Product No. 992, SOMAY “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.
FERROUS METAL (STEEL) SURFACES:
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
“Convertor”, 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 acidcontaminated 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:
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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 that is firmly or soundly adhered to the
steel substrate.
Primer:
Then “spot” prime the rust 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./gal. (or
19.26 sq.m./3.79 L) at 2 mils (50 microns) dry film thickness. “Rustbond” 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 the ferrous metal
primer shown above that is dry and cured.
PLEASE - always read completely the detailed instructions on the paint can label prior to
painting and please follow the instructions in every detail. These instructions are based on our
many years of experience formulating, manufacturing and distributing some of the finest,
highest quality, most durable paints available on the market today. Please don’t waste your
time, energy, money or our fine paint and coating products by ignoring the label instructions.
In summary, there is absolutely NO substitute for, and NO short cut to, proper surface
preparation. And without proper surface preparation, there is NO chance of a completely
satisfactory, long-lasting paint job. As we say on our SOMAY paint can labels, “The secret of a
successful paint job is proper surface preparation.”
RM-801-2012
August 2012
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