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Understanding Flooring Adhesives
Adhesives serve many
purposes in floor covering installation,
with the main purpose being to hold your
flooring in place. They may also be
formulated to have additional features to
protect your job. One such feature is
flexibility, as with urethane adhesives and
hardwood flooring which allow the wood to
expand and contract or soft setting re-tackable
carpet adhesives. Others such as ceramic
adhesives are formulated to be water
resistant, especially when used in high
water areas such as showers. That is why
there are two types of ceramic adhesives,
Type I and Type II. Type I may be used for
walls and ceilings in light construction
with wet requirements. Type II may be used
on walls and ceilings, light construction,
dry or limited water exposure.
Below
is a partial glossary to help explain some
of the terms we use both before and after an
installation problem.
We have all
heard of plasticizer migration, a term used
when plasticizers leave a flooring product
and enter an adhesive, turning it into a
soft, gooey mess with no holding power. An
example of this would be using a
multi-purpose adhesive with a vinyl-backed
sheet floor. The plasticizers in the
vinyl-backed sheet floor leech into the
multi-purpose adhesive, breaking it down
leaving a mess. A plasticizer is a product
that is used to soften and provide
flexibility in various flooring products
such as vinyl sheet goods and vinyl backed
carpet tile. Two examples of plasticizers
are mineral oil and hydrocarbon oil.
Plasticizers are also used in adhesive
compositions since it improves tack, and
develops “legs.”
The word polymer is
used extensively. A polymer is a compound
used in the adhesive’s components. It can be
natural rubber, styrene butadiene rubber
(SBR) or neoprene.
Binder is another
term not fully understood. A binder is the
substance that holds the adhesive itself
together. The adhesive actually gets its
common name from the binder. Some common
binders are rubber-resin, latex-resin and
asphaltic cut back.
Resins are solid
or semi-solid maternal. They are either
natural or synthetic. Usually insoluble in
water, their purpose is to improve adhesion,
improve tack, “wetting” of substrate, and
improve the film strength by stiffening the
film. Some common resins are vinyl, acrylic,
gum rosin, wood rosin and hydrocarbons.
Fillers are basically substances of a
non adhesive property. Fillers are added to
lower the cost and also improve
characteristics. Fillers control viscosity
and stiffen the film. Some fillers are clay,
silica, carbon black and calcium carbonate.
Of course none of the adhesives would be
worth much without additions such as
thickeners, antioxidants, light, and heat
stabilizers, and without preservative (to
prevent bugs), surfactants for wetting and
stability, and emulsifiers.
Now that
you know how an adhesive is made, we can
talk about some of the problems we see in
the field:
Balling-up: This
condition results when adhesive cannot be
troweled properly. Since wetting agents and
other goodies are usually present in the
formula, the most common reason for
balling-up is a dusty substrate, or when an
adhesive, from age, is losing stability.
Adhesive failure: This is an
occurrence where the adhesive fails to bond
to the substrate or the back of the flooring
product. If the failure is in the substrate,
look for dampness, curing compound or a weak
and dusty surface. If the failure is the
flooring itself, it most likely means poor
adhesive transfer due to a bad or wrong size
trowel, or waiting too long to place your
flooring, causing the adhesive to be skimmed
over, preventing transfer. Also, an
incorrect adhesive may have been used.
Cohesive failure: This is
failure within the adhesive itself. This
condition is identified by seeing a
separation, with adhesive bonding to the
substrate and the back of the flooring. This
can be caused by use of an improper trowel
size, installing too soon into wet adhesive
that hasn’t begun to firm up, or premature
movement of the flooring product itself or
even defective adhesive.
Freeze-Thaw Stability: This problem is
not all that it seems to be. For example,
one adhesive may be protected to 10 degrees
with 3 thaw free cycles. Another may be
protected to 0 degrees with a different
number of cycles. Sometimes the length of
time in hours can affect the reliability of
the adhesive, so protect your adhesive.
No longer are consumers limited to carpet,
sheet goods and tile – they can now enjoy
the resurgence of homogenous vinyl, along
with unique looks created from cork, bamboo,
exotic wood and luxury vinyl tile.
Contractors and installers looking to
maximize profit while minimizing the risk of
callbacks need to stay ahead of the curve
when it comes to new floor covering
products, to ensure they choose adhesives
that perform effectively.
Carpet
When choosing an adhesive
for a carpet installation, one must consider
the type of backing, necessary grab, traffic
load, maintenance schedule, and quality and
lifecycle of the carpet. Historically, the
two most popular carpet backings have been
ActionBac and jute. However, industry demand
for fast-track carpet installations as well
as new technologies and materials have led
to a new world of carpet backings,
including: smooth, rough and woven unitary,
hot-melt, Kanga, Karastan and solid PVC.
Moving from two-step to one-step added
carpet installation methods, such as with
Enhancer-backed carpet, meant that adhesives
also had to evolve to provide more
aggressive bonding. The majority of today’s
one-step carpet installations rely on the
use of styrene butadiene rubber (SBR)-based
adhesives due to their fast grab and
excellent re-tacking characteristics. For
builders and business owners desiring a
short-term carpet installation, an
economy-grade, SBR-based adhesive would be
suitable. On the other hand, a higher-end,
commercial installation expected to last
several years, which calls for double
glue-down application, would require a
higher-grade adhesive. For carpets without
design patterns where seams can be
“trace-cut,” an adhesive offering ultra
quick grab should be used. This will allow
the carpet to be rolled right away, ideal
for today’s fast-turnaround installation
schedule. More expensive, patterned carpets
require a higher-quality adhesive with
strong grab and appropriate slip time for
matching up the patterns.
Sheet-goods adhesives
It is
imperative that the sheet-goods backing
(e.g., felt-backed vinyl, PVC-backed vinyl
and solid PVC) dictate the choice of
adhesive for the installation, thus avoiding
the dreaded “plasticizer migration” syndrome
and subsequent callback. When an
incompatible adhesive is used to install
solid vinyl sheet-goods products, the
chances are high for experiencing bubbling,
severe discoloration and installation
failure. Avoid product incompatibility by
checking the flooring manufacturer’s
recommendation for proper choice of
adhesive. Be sure to consider the specific
application criteria that the sheet-goods
installation will be subjected to. For
example, if the floor-covering product will
be subject to heavy “point loads,” as in
healthcare facilities, a harder-setting
adhesive such as an epoxy adhesive should be
used. The reason for this is that the epoxy
adhesive sets up hard and will not indent
like most one-part latex based adhesives.
While a higher-quality, more durable
adhesive may cost a little more, the chances
of installation failure now and later drop
significantly.
Vinyl composition tile
While adhesive selection for a typical vinyl
composition tile (VCT) installation should
be foolproof, experienced installers could
tell you otherwise. Quite often, a VCT
installation appears flawless on the day of
installation but has tiles mysteriously out
of position on the following day. Chances
are, another construction trade trampled
across the floor, moving ladders or carts
and causing “fresh” VCT to slide. Having to
execute immediate damage control creates
much grief for both the floor-covering
installer and contractor. Spending a little
more money on an adhesive with a shorter
open time, very aggressive grab, ultra high
shear strength, and the proper trowel
notching is critical, particularly in
fast-track, heavy commercial flooring
applications.
Luxury Vinyl
Tile
This product category falls
in under the vinyl-backed adhesive category
and requires higher end vinyl adhesives.
Using a VCT Adhesive or a Multi-Purpose
Adhesive with these types of products will
lead to plasticizer migration failures.
Hardwood adhesives
Wood floor coverings continue to thrive and
are growing in popularity. Because wood is a
natural product, much consideration must be
given to the type of adhesive used in its
installation. The type of adhesive
appropriate for engineered wood product
installations is very different from that
for solid wood planks. As is the case for
all floor-covering products, wood products
need to acclimate according to
manufacturer’s recommendations. Because
solid wood products require a strong bond,
urethane-based adhesives are excellent
choices for holding solid wood in place.
Once cured, both of these high-quality,
solvent-free adhesives provide the needed
flexibility and superior bond strength that
solid wood installations demand. For
approved pre-finished, engineered wood, cork
and parquet floor-coverings, a water-based
adhesive is a choice pick due to its ultra
high tack and excellent re-bonding
characteristics. Before beginning any wood
product installation, always consult the
wood manufacturer to determine if their
product is recommended for glue down,
because some engineered woods must be
installed as floating or nail-down systems.
Keep in mind that in the world of
construction, warranties are given with only
one condition: The manufacturer’s
installation recommendations must be
followed. Before beginning any installation,
take the extra step of consulting with the
floor-covering and adhesive manufacturers
regarding the proper adhesives and trowels.
Doing so will help protect you from future
liabilities and teach you more about the
products’ characteristics and capabilities,
which pays off with an easier, faster and
more successful installation.
Need help call Tim Marion: 674-8839.
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