HOW TO APPLY
SURFACE PREPARATION
Sikafloor® MetalTop-300 can be applied to fully
cured or recently placed (less than 4 days old)
concrete.
SURFACE PREPARATION METHOD 1
Use this method on existing fully cured
concrete.
1. To achieve a proper bond with Sikafloor® MetalTop-300, the surface of the concrete should have
a 1/4" (6 mm) amplitude profile (ICRI CSP
#9). Remove all laitance and contaminated
areas, creating a coarse profile and exposing
aggregates. Multiple passes with a shotblast
machine using heavy shot have proven effec-
tive. If a bush hammer or scarifier is used,
follow with abrasive blasting. The surface
must be completely clean and free of oil,
grease, dirt, and dust.
2. Test the concrete surface for tensile-bond
pulloff strengths according to ASTM C 1583.
The minimum tensile-bond pulloff strength
must be at least 200 psi and substantial coarse-aggregate fracture must be revealed.
Perform the test in several locations on each
slab section scheduled for placement of
Sikafloor® MetalTop-300.
3. The base slab (substrate) surface must
comply with Section 4.2 of ACI 503.5R.
This section is specific to the surface, acces-
sibility, and temperature conditions during
the application of the epoxy bonding agent.
4. Joints are terminations should be pre-treated in one of two methods:
- Mechanical fasteners such a Hilti short nails or Tapcons should be installed in two, offset rows on 12"-18" centers, 4"-6" away from the joint. Note that pneumatically applied fasteners could introduce damage in the substrate.
- An "armored" joint can be introduced on each side of the joint by chipping 4" back from the joint to a depth of 1".
5. Before placing Sikafloor® MetalTop-300, test the
concrete in accordance with ASTM D 4263,
Indicating Moisture in Concrete by the Plastic
Sheet Method. Excessive moisture must be
force-dried to produce a condition suitable
for the bonding material to achieve proper
bond strength. Internally moist concrete
may cause vapor pressure upon curing and
delaminate the topping.
6. Fill all pre-existing cracks in the concrete
with a suitable epoxy crack-repair material.
Consult your Sika representative for recom-
mendations.
7. Use liquid epoxy bonding agent such as
Sikadur® 32 Hi-Mod LPL to bond the topping to the
existing concrete. Mix according to directions
and brush, spray or roll the agent onto the
concrete surface. Place the topping while the
epoxy is still tacky, like fly paper. If already
set, brush more over the hardened surface.
Do not attempt to retemper with solvents.
8. Make sure to cover the surface with the top-
ping before the epoxy loses its tack.
SURFACE PREPARATION METHOD 2
Use this slurry-bond-coat method on recently
placed (less than 4 days) concrete.
1. The concrete must be designed to have a
minimum of 4,000 psi at 28 days, in accor-
dance with ACI 302 recommendations.
2. After placing, screeding, and floating the base
concrete, spray on a liquid surface retarder at 100 – 120 ft2/gallon. Cover
with polyethylene, burleen, or other impervious sheet covering to keep the surface from
drying out. Remove the covering within 4
days. Use a pressure washer with sufficient
power to expose the aggregate and ensure
a 1/4" amplitude. Rinse until water
runs clean.
3. The concrete surface must be saturated
before the placement of Sikafloor® MetalTop-300.
Remove standing water immediately before
the application of the bond coat.
4. Use properly mixed Sikafloor® MetalTop-300 as a
scrub coat. Scrub into the damp surface
with a clean, stiff-bristle broom just before
the application of Sikafloor® MetalTop-300. Do not
apply at an excessive thickness. Do not leave
any puddles.
Limit scrub application to an area that will
assure the Sikafloor® MetalTop-300 topping can be
placed before the scrub coat dries. DO NOT
RETEMPER the bond coat with water.
MIXING
1. Use an appropriate forced action mortar
mixer for the job. Add 3/4 of the mixing water,
followed by Sikafloor® MetalTop-300 in a slow, steady
stream. Mix for approximately 2 – 3 minutes.
Add the remaining water and continue mixing
for a total of 5 minutes. Mix thoroughly for a
homogeneous mix at the recommended slump.
For bulk bags mixing, refer to technical bulletin
for mixing Sikafloor® MetalTop-300 bulk bags.
2. Using ice water will reduce water require-
ments for a given consistency and will result
in increased working time and strength of the
topping. Do not use water in an amount that
will cause bleeding or segregation.
3. Discharge the topping from the mixer for im-
mediate placing and screeding. If lumps are
present, remove them.
Note: 0.63 U.S. gallons per 55 lb bag 38 U.S. gallon is the
recommended amount of water for a 6" slump mix.
APPLICATION
1. Place and screed the Sikafloor® MetalTop-300 in
sections to maintain the finished elevation.
Periodically measure the topping thickness,
especially in the center of the slab. Because
of the relatively high slump of Sikafloor® MetalTop-300,
a roller or pipe screed works best for obtain-
ing a uniformly flat, dense surface without
excessive segregation from vibration.
2. As soon as Sikafloor® MetalTop-300 will support
an operator and machine without leaving
impressions on the slab or creating excessive
fines at the surface, float with a mechanical
troweling machine equipped with float shoes.
For small areas, floating with hand tools is
acceptable.
3. Following 1 machine floating, proceed with
1 or 2 normal troweling operations to obtain
a hard steel-trowel or burnished-trowel finish.
Time the troweling operations and adjust the
blade angles to avoid blistering.
4. Sikafloor® MetalTop-300 can be applied in a monolithic
two-course application over fresh concrete.
This type of application requires extreme skill.
Please contact your Sika representative
before attempting this kind of application.
Under rapid drying or hot, ambient condi-
tions, Sika evaporation reducer Sikagard-30 ER
should be sprayed from a garden sprayer, ac-
cording to label instructions, to prevent rapid
moisture loss from the Sikafloor® MetalTop-300.
CURING
1. Sikafloor® MetalTop-300 must be moist cured to attain
its proper design strength, surface imperme-
ability, and wear resistance. After finishing
has been completed and the surface will not
be marred by foot traffic, mist spray the sur-
face of the topping with water, keep wet and
cover it with weighted polyethylene sheeting
for a minimum of 7 days. When mist spraying
is not possible, use soaker hoses with burlap
or 2 layers of saturated burlap (or similar
moisture-retaining sheet material) and cover
the surface with polyethylene for a minimum
of 7 days.
2. After 7 days of wet curing and while the
Sikafloor® MetalTop-300 is still moist, remove excess
water with a squeegee. Immediately apply an
appropriate curing compound (consult your
Sika representative for recommendations).
Using a roller will ensure complete coverage
with the curing compound. Do not spray-
apply a membrane curing compound unless it
will be backrolled. Do not allow the Sikafloor® MetalTop-300 to dry out before the application of the
curing compound.
If the floor must be returned to service in less
than 7 days, contact Sika technical support
prior to installing Sikafloor® MetalTop-300.
JOINTS
Joints and proper joint spacing are necessary
to limit the cracking tendencies in the topping
from shrinkage (contraction joints), to limit
movement between the floor and other
structural members (isolation joints), and
to conclude pours from one day to the next
(construction joints).
Procedures for determining the base-slab
joint locations, spacing, depth, etc., should
be conducted in accordance with ACI 302.1
R-6 section 2.3.
The maximum joint spacing should not
exceed 20 feet. Base-slab joints must be
matched in the Sikafloor® MetalTop-300 topping by
forming or other suitable means.
Note: Intermediary joints must use anchors
when Sikafloor® MetalTop-300 is placed on hardened
slabs (Method 1) where the joint spacing
exceeds 20 feet. See your local Sika sales
representative for further recommendations.
