How to Guide
SELF-LEVELING UNDERLAYMENT
CONDITION 3: Invisible contamination such as sealers, curing
compounds or oil.
Evaluation: Sprinkle water onto the surface. If water forms
droplets without absorbing immediately, the surface is probably
contaminated.
Preparation: Contaminated concrete must be removed by
mechanical method such asshot blasting.
Curing Compounds
Petroleum based, wax emulsion or dissipating curing
compounds must be removed by mechanical means
such as shot blasting. If the type of curing compound is
unknown, removal is required.
Silicate or Acrylic resin curing compounds may be
acceptable. Install primer test sample areas to evaluate
bond strength first. Samples must achieve 72 psi (0.5
MPa) tensile bond strength. For silicate types, all
residual salts must be removed prior to application of
the primer and underlayment.
CONDITION 4: Surface dirt and dust.
Evaluation: Wipe the surface with a clean dark cloth. If powder
is visible on the cloth the surface is not clean enough. Note the
areas that require cleaning.
Preparation: Always use a two-step method to remove surface
dirt and dust. First use a dry clean broom and sweep the entire
surface. Do not use sweeping compounds. They can leave an
oily or waxy film on the concrete surface that will prevent a
proper bond. The second step should consist of one of the
following:
Vacuuming – use a heavy-duty industrial type vacuum
to provide a dust-free surface.
Water cleaning – use a stream of potable water with
sufficient pressure to remove dust and dirt. When
necessary, also scrub with a stiff bristled brush.
Thoroughly remove all wash water and allow concrete
surface to dry prior to application of any TEC® Skill
Set™ materials.
Detergent water cleaning – Using a stiff bristled brush
or broom, scrub the entire concrete surface with a
cleaning product intended for concrete or a solution of
at least 4 ounces (118 ml) of trisodium phosphate per
gallon (3.78 L) of warm water. Before the surface dries,
thoroughly flush the concrete with clean potable water
to remove all wash water and residue. Allow concrete
surface to dry prior to application of TEC
®
Skill Set™
materials.
Single Layer of Exterior Grade Plywood or Oriented Strand
Board (OSB) with Lath: Wood subflooring must be securely
fastened with screw type or ring shank nails and adhesive.
Installations of exterior grade plywood or OSB (APA Rated
Sturd-I-Floor OSB, Exposure 1 or better) require 3⁄4" single layer
minimum thickness on bridged floor joists up to 24" on center,
with a maximum deflection of L⁄360 of the span. Allow a gap of
1⁄8" to 1⁄4" between sheets of plywood or OSB. Long edges of
subfloor must be tongue and groove or supported by bridging
between floor joists. Use TEC
®
Skill Set™ Fast Setting Patch to
plug all floor openings, gaps and cracks and install termination
dams to prevent any seepage. Prime the floor and allow it to dry to
a clear film. Next, staple 1⁄4" galvanized diamond metal or plastic
lath to the floor overlapping 2" at seams. Staple every 6" around the
perimeter and overlaps, and every 8" in the field of the lath. Install
TEC
®
Skill Set™ Self Leveling Underlayment based upon the
following joist spacing in the table below:
Joint Spacing
(o.c)
Minimum SLU thickness with lath
over single layer ¾ in. tongue and
groove subfloor
16 in. or less
3/8 in.
20 in. or less
1/2 in.
24 in. or less
5/8 in.
Double Layer of Exterior Grade Plywood without Lath:
Exterior Grade Plywood subflooring must be a minimum
thickness of 5/8”, securely fastened with screw type or ring
shank nails and adhesive. Maximum floor joist spacing is 16”
o.c. with a maximum deflection of L/360 of the span. Allow a gap
of 1/8” to 1/4” between sheets of plywood. Long edges of
subfloor must be tongue and groove or supported by bridging
between floor joists. Install Exterior Grade Plywood
underlayment, minimum thickness of 5/8” with 1/8” gap between
sheets. Underlayment fasteners shoud not penetrate joists
below. For ¾” tongue and groove subfloor thickness over joists
16” o.c., install Exterior Grade Plywood underlayment, minimum
thicikness is ½” with 1/8” gap between sheets.
Use TEC® Skill Set™ Skimcoat & Patch to plug all floor openings,
gaps, and cracks and install termination dams to prevent any
seepage. Prime the floor. Allow primer to dry to a clear film.
Maintain minimum thickness for TEC® Skill Set™ Self Leveling
Underlayment of 3/8”.
Radiant Heating Systems: For radiant heat system installations,
always prime the substrate before installing heating system
components on the substrate surface. Heating system must be off 2
days before and kept off for 7 days after installation.
Electric Wire Systems Installed Over Substrate – TEC
®
Skill Set™
Self Leveling Underlayment may be used in conjunction with wire
systems installed over concrete, single layer plywood/OSB
subfloors with plastic lath or double layer plywood floors without
lath. Follow the requirements for each substrate stated above and
maintain minimum thickness of self-leveling underlayment above
the wire of 1⁄4".