Modern
technology has developed wood flooring qualities and
finishes that have never before been available. Never have
there been more colors, patterns, styles, and types of wood
floors. The technology that has emerged from the chemical
and adhesives companies has contributed greatly to the use
of wood flooring and expansion in commercial and residential
construction. New adhesives today enable us to use wood
floors products in applications that just a few short years
ago would have been prohibitive. These new adhesives in turn
have contributed greatly to the increased use of wood
flooring in all types of new construction as well as in
remodeling.
It has not
always been this way. Limitations were placed on the use of
wood flooring in many areas because of the lack of good
installation systems. It has only been in the last 50 years
that adhesive installed floors have become common. It is
interesting to look back over these 50 years and see just
how adhesives have played a role in the growth of the wood
flooring industry and how the evolution of different
adhesives occurred, each solving some problems of its
predecessor but creating new problems of their own.
Let's examine
this evolution by adhesive types. And examine the pros and
cons of each adhesive type or system. We'll then take a
crystal ball look into the future to see what may lie ahead
of us in a world of modern technology that constantly faces
government and political controls.
The very first
installer of wood flooring with adhesives was probably an
ex-roofer. He had an old smelly asphalt wagon that he
practically set on fire to soften the asphalt into a
workable consistency. While the application was not very
pleasant, his mentality was exceptionally keen to have the
foresight to experiment with these asphalts for installing
wood flooring. The system was simple in a way but very
difficult and definitely not the type installation that even
the experienced flooring installer could easily master.
Nevertheless it worked, by hot mopping asphalts on a
substrate and then embedding wood flooring into the asphalt.
Thus, adhesive installed wood flooring systems were born.
One can only be
somewhat awe struck by the problems with this type of
application. Without a doubt it was messy; results were
inconsistent; it was smelly; it was somewhat hazardous;
clean up of smears and slop overs was nearly impossible;
mistakes and repairs were difficult to handle. About the
only good thing was that for the first time someone had the
idea for a new method of installing floors that would
ultimately contribute greatly to the tremendous growth that
the industry has experienced.
Without a doubt
the old smelly asphalt furnace on a trailer had to go and be
replaced by some type of system that was controllable and
easier to apply. Since asphalts were already being used,
then why not continue to use asphalts but devise a better
application method. This thinking led to the development and
use of "asphalt cut-backs". They were called "cut-backs"
because the old solid blocks of asphalt were "cut-back" with
a flammable solvent such as mineral spirits, to make them
fluid. They were then filled with materials, sometimes
asbestos, to provide a uniform viscosity or thickness. Now
an adhesive was available that could be purchased in a
container, actually troweled on a substrate, and then you
install wood flooring in the asphalt mastic. The release of
the solvent caused the asphalt to 64 set up" and provide a
bond. This type material is still used today. It overcame
many of the problems of the old hot-mopped asphalt but then
it created some very important new problems.
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The most
serious problem was that of flammability. It was not
uncommon to trowel out very large areas before
installing any flooring because the working times were
extremely long. This saturated the surrounding areas
with solvent vapors and carelessness on the part of the
mechanics caused serious fires and explosions.
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The
flammability resulted in greatly increased insurance
premiums.
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The
technology involved in the formulation was not very
sophisticated and some very questionable compounds began
formulating these materials.
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Asbestos, a
common filler that was low in cost, was used but later
found to be an extremely hazardous material for the
compounds to handle and ultimately was banned. The
result was formulation with different fillers that
increased prices of an already questionable material.
Clearly, the
days of asphalt cut-backs were numbered and something had to
be done to replace these materials for the installation of
wood flooring. Mastic application of wood parquet floors was
firmly in place in the industry. The market had become
sizable and new flooring products were being developed by
the manufacturers that required a quality mastic without the
inherent problems of the asphalt cut-backs. Thus the modern
day chlorinated solvent mastics and some emulsions for
special applications of finger block were developed.
To many, this
sudden evolution from asphalt cut-backs into chlorinated
solvent and emulsion formulations came as a shock. All of a
sudden the price per gallon of adhesive sky rocketed and the
days of $1.00 per gallon asphalts were gone forever. From an
industry point of view however, this was not all bad because
for the first time a technology was spawned that was
instrumental in the rapid growth of the wood flooring
industry. The technology created some very important
situations and advantages.
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For the
first time the burden of performance was placed on the
manufacturers of the adhesives. Heretofore, this
responsibility rested almost entirely with the installer
and he was at the mercy of the quality level of the
cut-backs. The installer was also liable for the
hazardous characteristics of the adhesive.
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The ease of
application and use of these new mastics opened up new
horizons for installers that previously would not have
attempted to install wood floors in mastics.
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For the wood
flooring manufacturers, it presented new opportunities
for research and development of different patterns and
flooring types, thereby expanding the market.
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Eliminated
were the hazards associated with flammable products
which resulted in reduced insurance rates and liability.
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The
technology involved in the formulation and manufacture
of these new mastics is provided by manufacturers who
are far more sophisticated in their research,
development, and production than the manufacturers of
the past. No longer is it possible to set up a "garage
operation with a cement mixer" to produce these
formulations. You are for the most part supported by
reputable and quality oriented manufacturers.
Just what is it
about these chlorinated mastics that is so good? Why is it
they have become so widely used in spite of their higher
cost? What characteristics do they possess that are not
totally desirable and may make them questionable in the
future?
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First and
foremost they are non-flammable. With today's government
constraints, you just cannot use the hazardous,
flammable products of yesteryear on flooring
installations.
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Because of
their non-flammability, your exposure to liability is
far less.
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The
elastomeric chlorinated systems possess most of the key
application requirements such as ease of application,
high green grab (tack), long working time and high
strength. They really have most of the good application
characteristics of the cut-backs plus some added
benefits and few of the negatives.
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They are
easier and cleaner to use.
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They have
excellent long term aging characteristics if properly
formulated.
They are
not, however, free from negatives.
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Chlorinated
solvents as a class have some pretty bad actors among
them. Although most of the chlorinated solvents used in
adhesive formulations are relatively safe to use and are
not generally considered a carcinogen by the EPA or
OSHA, there are some blends of 1, 1, I trichloroethane
that may be questionable. To be on the safe side, be
sure that your manufacturer uses pure 1, 1, I
trichloroethane rather than blends in his formulation.
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Prices
continue to escalate on chlorinated solvents that could
eventually limit the market.
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The odor is
extremely pungent and you must use adequate ventilation
and air circulation while in use.
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Under
certain conditions, without adequate ventilation, air
circulation, and the extinguishing of all flames in the
area, they can create an atmosphere that will be
corrosive to metallic surfaces throughout a home or
structure.
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When used
over existing vinyl floors, they can cause a migration
of plasticizers between the vinyl floor and the mastic,
that will not permit the mastic to set up. This problem
is avoided by using primers designed to provide a
barrier between the mastic and the vinyl floor, as well
as an improved bonding surface. Incidentally, this is
not peculiar to only chlorinated mastics. Migration can
also occur with emulsion formulations over vinyl.
At the present
time, chlorinated mastics are the most widely used in the
industry and will continue to be for the immediate future.
What will
replace the elastomeric chlorinated systems and be the
product of the future? The basic technology is already in
place and being used. It is similar to that used in the
emulsion polyvinyl acetate (PVA) systems. The future may be
in the development of emulsion polymers that can be adapted
to wood flooring applications of all types, even though they
are water based. After all, we are already doing this with
the PVA emulsion products on finger block installations.
What does this
wood floor industry of ours want from a mastic, and how must
it work? We want mastics that are:
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Safe to work
with.
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Keep a floor
down forever under normal conditions.
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Less
expensive.
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Fast and
easy to complete the jobs.
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Compatible
with a moisture barrier over concrete slabs.
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Not going to
overstress the substrate as the wood expands, yet return
a shrinking floor.
Mastics must
work by holding the floor with a dry, elastic, "stretchy"
bond. The original roofer used asphalt that turned brittle,
then as the wood changed dimension during season changes,
the floor popped loose. The same is true for rigid/ stiff
epoxies today. Even though extremely strong, as the wood
moves the substrate fractures and there goes the floor.
Cut-back asphalt holds the floor by suction and lets wood
move or "float," but we've already covered the problems of
this adhesive type. The mastic when spread must hold the
bead of a notched trowel to insure positive contact with the
wood when used over a less than perfect subfloor (all of
them).
There are
several other types of adhesives out there at this writing,
namely:
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Contacts
that either are solvent-laden and dangerous, or
water-laden and can destroy the wood. With both you must
coat both surfaces, let them dry, then position the
piece perfectly the first time!
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Polyurethane's that are strong, elastic, age well and
are water resistant, but are sometimes toxic, always
costly, and difficult to use.
At this point in
this study you can see how today's chlorinated solvent
adhesive meets so many of our needs. The qualities of
"strong," "dry," "elastic," "bead-holding" all apply and
sound like rubber. Rubber sounds like "latex." Latex
emulsion sounds like a mix of rubber with solvent or water.
Solvents sound dangerous and expensive. Water sounds
inexpensive and safe.
Thus we have
come full circle, back to our crystal ball. The adhesive
system of the future will be a water emulsion latex designed
to eliminate warp and grain raise of wood floors. Needless
to say, the adhesive and chemical manufacturers have a tough
assignment! But realize that we no longer must set fire to
an asphalt trailer -- and we have walked on the moon!
Another major
consideration in the future will be waste disposal,
particularly containers. The old fashioned trash man or
garbage man will truly become a "waste engineer. As a matter
of fact he already is one. Many of these waste collectors
have been trained to keep their eye open for dumpster
disposal of hazardous materials and they are notifying the
EPA when they find them, resulting in some very costly
situations for everyone involved.
Picture if you
will the large volume of all types of adhesives used in just
flooring applications on a high rise office building.
Disposal of sometimes thousands of empty containers is
getting to be a major problem. The problem is even greater
when the mechanics fail to thoroughly wipe out the pails
before disposal. We are about to see s o me major changes in
packaging of all types of products in industry, particularly
those containers that originally held products that even
remotely might be considered hazardous waste.
New containers
and new products will also generate new methods of
application for adhesives of all types. Higher labor costs
will also ultimately dictate that more mechanically applied
systems be developed to accommodate all of these changes.
The 1990's will
see many changes and innovative ideas in our industry. The
installers of the future must remain open minded and be
willing to participate in these new ideas. At the same time
they must remain honest and practical, keeping in mind that
they have an obligation to provide their customers with the
best and highest quality installation possible. Always deal
with well known, reputable suppliers and don't try to be
penny wise and pound foolish by taking unnecessary risk with
lesser quality or lower cost materials. Protect yourself and
your customer by following the recommendations of the
manufacturer. Be willing to try new ideas.
Today's
technology has formulated parquet and engineered wood
flooring adhesive that are Solvent-Free, VOC-Free, and non
toxic. With fast setting formulas, no tack and flash time
for the installer. The two part urethane adhesives will
surely making installation of the new breed of engineered
wood floors much, much easier to work with.
