Surface Preparation for Resin Systems
Surface Preparation Guide
For Concrete, Wood, and Metal Substrates
I. GENERAL INFORMATION
Surface preparation is considered to be the most important step of any
resinous flooring application. Improper surface preparation could turn what
seems to be a simple process into a lengthy, difficult repair. The following
conditions will dictate the type of surface preparation:
A. Concrete Placement
1. Slab-on-grade or on the ground
a. A 10 mil minimum vapor barrier is necessary to prevent moisture vapor
transmission. An efficient puncture proof barrier is recommended.
b. Proper jointing will minimize cracking which could transmit through
the resinous flooring system.
2. Elevated Slabs
a. Pan construction should be vented.
b. Metal deck construction should be properly jointed to minimize
B. Curing and Finishing Techniques
1. Curing compounds, if used, must be mechanically removed from the concrete
surface prior to all resinous flooring applications.
2. Recommended techniques:
a. Wet cure
b. Light steel trowel finish to minimize laitance and provide hard
C. Age of Concrete
Concrete must be a minimum of 30 days old for resinous
flooring applications. Primers are now available which can be
used on fresh (green) concrete on some installations. Contact
the technical department for details.
D. Previous Contamination can
affect the bond of the resinous flooring and must be removed. Types of
1. Oil, grease, or food fats can usually be burned off with a
flame gun or removed with a commercial degreasing compound or solvent.
2. Curing compounds, sealers, and other laitance are best removed
a. vacuum shot-blasting
c. sand blasting
E. Present Condition
1. Test for moisture:
Coating system bond failures on slabs on grade and elevated/lightweight
concrete caused by moisture vapor transmission are the industry's largest
single problem and result in extreme frustration from owners, clients, and
contractors. Epoxy.com recommends testing for moisture
vapor transmission. The recognized methods are:
a. ASTM-F-1869 – Standard Test Method for Measuring Moisture Vapor
Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride: The
maximum allowed water/vapor transmission rate is 3 pounds per 1,000 square
feet per 24 hours.
b. ASTM F-2170 – Standard Test Method for Determining Relative
Humidity in Concrete Floor Slabs Using In Situ Probes: This test
measures the relative humidity in the slab below the surface. If taken over
a period of time, it will show the rate of drying in the slab. The maximum
relative humidity should be below 80%.
c. ASTM-D-4263 – Plastic Sheet Test: This test gives an indication
that moisture may be present.
2. Moisture related failures can be prevented through:
a. Placing new concrete over an efficient vapor barrier.
b. Testing for moisture vapor transmission as prescribed above prior to
resinous flooring application.
c. Applying a moisture vapor transmission reduction system where moisture
content is too high for successful resinous flooring applications.
3. A clean surface is necessary to establish a strong bond between the
resinous flooring and concrete.
4. Resinous flooring systems are only as sound as the concrete they are
applied to. All unsound concrete should be repaired or replaced prior
to resinous flooring applications. Consult your Epoxy.com Technical
Service Department for specific information.
5. Resinous flooring materials should be applied to level concrete
substrates. Grind or fill high and low spots prior to application.
6. Repair cracks prior to resinous flooring applications.
F. Mechanical Prep vs. Acid Etching
Resinous flooring materials ideally bond to concrete with a rough,
sand-paper finish. This finish can be
achieved by either acid etching or mechanical methods. The choice of
preparation is dictated by the factors above. Other factors which determine
the type of preparation include:
1. Ecological restrictions involved with waste removal which could
prohibit the use of acid etching and other chemical methods.
2. The type of resinous flooring material: It is recommended that
concrete floors be acid etched prior to application of polyester and vinyl
ester flooring systems.
G. Acid Etching
The following steps are recommended for acid etching:
1. Dilute commercial muriatic acid with water using 1 part acid by volume
to 3 parts clean water by volume. Add the acid slowly taking care to avoid
splashing. Workers should be protected with safety glasses, rubber gloves,
and boots. If skin or eye contact occurs, rinse affected area thoroughly
with clean water and follow Material Safety Data recommendations.
2. Sprinkle acid solution onto the entire surface in order to allow the
acid to reach all areas of the concrete. Adequate coverage is approximately
75 ft²/gallon of acid/water solution. Do not puddle and spread.
3. Scrub the acid solution into the concrete using a stiff bristle broom
to remove loose concrete and laitancy.
4. Before rinsing, look for areas where bubbling did not occur. These
areas have not been sufficiently cleaned and will require mechanical
scarifying and additional acid etching.
5. When the acid solution has stopped bubbling (usually after
approximately 15 minutes), rinse the floor thoroughly with water. Do not
allow the floor to dry before rinsing because the salts formed by the acid
reaction may cause problems with the adhesion and performance of the
resinous flooring system. Test pH of the concrete surface to verify that the
concrete tests alkaline.
6. Finally, the floor should be dry mopped to remove standing water and
dirt remaining after the acid etching. Allow the floor to completely dry
prior to the application of any resinous flooring system. Failures can occur
in resinous flooring system applications due to moisture remaining in the
H. Mechanical Preparation
Contamination and other foreign materials must be mechanically removed to
ensure a satisfactory bond. All dust and debris must be thoroughly removed.
II. OLD CONCRETE
Old concrete surfaces must be structurally sound. Any
unsound areas must be repaired prior to proceeding with the resinous
installation. For proper patching and repairing, use Epoxy.com Technical Service
Department. Remove existing paint, scale and loose concrete by rough
sanding, sandblasting, shot blasting, or grinding. In some cases where plant
conditions allow, a stripper may be used to remove excessive build-up of
paints or sealers.
Structurally sound concrete should be mechanically prepared to remove any
contamination. Vacuum shot blasting is the best method for achieving a good
profile for bonding and should be used where possible. Before installation
of any Epoxy.com Product the surface must be examined for moisture
vapor transmission using:
ASTM-F-1869 Standard Test
Method for Measuring Moisture Vapor Emission
Rate of Concrete Subfloor Using Anhydrous
ASTM-F-2170 Standard Test
Method for Determining Relative Humidity in
Concrete Floor Slabs Using In Situ Probes.
ASTM-D-4263 Standard Test Method for Indicating Moisture in Concrete by
the Plastic Sheet Method. This test is only an indication and should not be
used to determine moisture migration.
Other ASTM Tests which are applicable to concrete preparation are:
ASTM-D-4258 Standard Practice for Surface Cleaning Concrete for Coating
ASTM-D-4259 Standard Practice for Abrading Concrete
ASTM-D-4260 Standard Practice for Acid Etching Concrete
ASTM-D-4261 Standard Practice for Surface Cleaning Concrete Unit Masonry
ASTM-D-4262 Standard Test Method for Ph of Chemically Cleaned or Etched
ASTM-C-811 Standard Practice for Surface Preparation of Concrete for
Application of Chemical Resistant Resin Monolithic Surfacing
III. NEW CONCRETE
New concrete must be well cured and dry prior to coating. Allow to cure a
minimum of 28 days unless using green concrete primer. No curing agents or
sealing compounds should be used at any time prior to coating. A light steel
trowel finish is recommended when finishing the concrete surface.
Any oil, grease, laitance, or other foreign material must be removed.
Steam clean with a strong degreaser such as tri-sodium phosphate. Laitance
and other foreign material are best removed by mechanical methods such as
vacuum blasting, scarification, or grinding.
All new concrete can be acid etched or mechanically prepared by vacuum
shotblasting, sand blasting, scarifying, or grinding. Vacuum shot-blasting
provides the cleanest environmentally safe area during cleaning. It also
provides a mechanically rough surface to achieve a good bond.
When acid etching, use a 3 to 1 dilution of water to acid and follow
directions printed above.
Before the installation of any Epoxy.com resinous system, the surface should be
examined for moisture. Test for moisture vapor transmission using ASTM
F-1869 Standard Test Method for Measuring Moisture Vapor Emission Rate of
Concrete Subfloor Using Anhydrous Calcium Chloride.
The maximum allowable rate is 3 pounds
per 1,000 square feet per 24 hours.
Another procedure that helps determine slab dryness is ASTM-F-2170 –
Standard Test Method for Determining Relative Humidity in Concrete Floor
Slabs Using In Situ Probes. Maximum allowable R.H. for protimeter test is
I. GENERAL INFORMATION
Resinous flooring must always be applied directly to exterior grade
plywood with extended glue line INTERIOR GRADE PLYWOOD
delaminates easily and SHOULD NOT BE USED as it could result in a
failure of the resinous flooring system. MARINE GRADE PLYWOOD
contains moisture repellants which could cause a darkening of the resinous
flooring system and SHOULD NOT BE USED. All plywood must be
completely free of all waxes, varnishes, or other foreign materials.
A. Plywood used to cover existing wood floors
1. Clean and fasten existing wood floor to the floor joists.
2. If the floor is completely sound, fasten ½ Exterior grade plywood
"C" plugged with an extended glue line to the existing floor. Stagger
the plywood for strength.
3. ¾" DFPA Exterior or ¾" DFPA Underlayment grade plywood with
exterior glue line must be used if the existing floor cannot be cleaned,
or is not sound.
4. All plywood must be completely free of all waxes, varnishes, or other
5. Secure plywood with exterior glue.
6. Use Ring Shank or Wood Screws at six (6) inch centers
around panel edges and support.
7. Stagger all panel joints, fill joints with epoxy filler, and cover
joints with fiberglass cloth and epoxy resin.
8. Lightly sand the floor surface to insure proper adhesion of the
resinous flooring system.
9. Prime surface with appropriate primer prior to system application.
Surface may require double priming due to porosity of plywood.
B. Plywood used for new construction (plywood is laid directly on the joist)
1. ¾" exterior grade plywood "C" plugged with an extended glue line
must be used.
All plywood must be completely free of all waxes, varnishes, or other
2. Use Ring Shank or Wood Screws at six (6) inch centers
around panel edges and support.
3. Stagger all panel joints, fill joints with Epoxy.com
Product #703. For outdoor applications cover joints with fiberglass cloth
and the membrane system being used with the outdoor system.
4. Lightly sand the floor surface to insure proper adhesion of the
resinous flooring system.
5. Remove all dust with a vacuum cleaner.
C. Applications with waterproofing:
1. After preparing the floor surface as prescribed above, caulk all
joints with Epoxy.com Product #703 for indoor systems. For
outdoor systems use the membrane used with the Epoxy.com outdoor system.
2. Apply the waterproofing membrane as specified.
I. Preliminary Preparation
A. Metal substrates must be structurally sound prior to any resinous
system being applied.
B. Remove all foreign materials such as oil and grease with solvents or
other degreasing compounds.
C. All scaling and rust must also be removed mechanically by sanding,
sandblasting, or abrasion.
II. Treat the blasted/abraded surface with a phosphoric acid solution as described below in order to prevent
rust formation if the surface is left exposed for some time prior to
application of the resin system.
A. Always use a 10% solution of Phosphoric Acid.
B. Mix acid solution in either glass, plastic, or earthen containers
(never use metal containers), by adding Phosphoric Acid to water. NEVER
VICE-VERSA due to heating or splashing which may occur.
Workers should be protected with safety glasses, rubber
gloves, and boots. If skin or eye contact occurs, rinse
affected area thoroughly with clean water and follow
Material Safety Data recommendations.
C. Apply phosphoric acid solution by either paint brush or rubber
squeegee and allow metal surface to AIR DRY.
DO NOT FLUSH METAL SURFACE WITH WATER.
III. Protect surface from contamination until the primer is applied.
IV. Wipe metal surface with MEK solvent immediately before primer