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
cracking.
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
surface
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 contamination are:
1. Oil, grease, or food fats can usually be burned off with a
flame gun or removed with a commercial degreasing compound or solvent.
Epoxy.com Product #201 Oil Stop Primer
is an important tool in dealing with petroleum oil contaminated concrete.
2. Curing compounds, sealers, and other laitance are best removed
mechanically with:
a. vacuum shot-blasting
b. scarifying
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. See Epoxy.com Product #830
Moisture Vapor Treatment for more details
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 square feet /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 substrate.
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 Calcium Chloride.
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
for Coating
ASTM-D-4262 Standard Test Method for Ph of Chemically Cleaned or Etched
Concrete Surfaces
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 80%.
WOOD SUBSTRATES
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 3/4 inch Exterior grade plywood
"C" plugged with an exterior glue line to the existing floor.
Stagger the plywood for strength.
3. 1/2" DFPA Exterior or 1/2" 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
foreign materials.
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. Seal all joints and fastener head holes with
Epoxy.com Product #703 - Semi-Flexible Epoxy Gel Adhesive.
10. 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. 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
foreign materials.
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, for indoor
systes caulk all
joints with
Product #2005 - or
Product #2704. In additon 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. For best results Sandblast to Commercial Blast (SSPC10 / NACE3)
for non-immersion applications and Sandblast to near white metal -
(SSPC10 / NACE2) for immersion applications.
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
application.
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