General information on floor finishing
Floors
can be finished in a very wide variety of products and materials including:
natural stone, double-fired floor tiles and other tiles, linoleum, vinyl, carpeting
etc. But floors can also be finished in various types of synthetic coatings.
Only the latter option will be discussed here within the framework of the
product range supplied by Baril Coatings.
10.1 Floor
requirements
The choice of the finish to be applied must also take the specific
characteristics of the surface into account. In addition, the surface must
satisfy several specific requirements before the finishing process is started:
The surface must be clean, dry and free of oil and grease. In other
words, all foreign elements must be removed in order to facilitate the
effective adhesion of the finishing layer. This may require a cleaning and/or preliminary
treatment step.
The surface must be mechanically stable. In other words, the strength at
the surface may not (noticeably) differ from the average strength. This is
necessary to ensure long-term adhesion, particularly when subjected to mechanical
and thermal loads. This prevents separation of the finishing layer together
with the top layer of the substrate.
Whenever possible, ‘upwards moisture penetration’ must be prevented. In
the case of new concrete floors, this can be realized by pouring the concrete
on top of an impermeable foil. For concrete floors, the moisture content of the
floor may not exceed 3% at the moment that a floor finish is applied which is
impermeable to moisture.
10.2 Preliminary treatment of floor
The preliminary treatment of a floor needed to ensure a good finish can
be realized physically, chemically or mechanically. The type of treatment
chosen or combination of such treatments will depend upon the presence of
foreign contaminants, the stability, and the nature of the floor substrate.
Physical cleaning processes are carried out with the help of
solvents/stripping agents, which can be used for example to remove paint and/or
glue residues. Chemical pretreatment includes the removal of all types of
contaminants with the help of neutral, acidic or alkaline cleaning agents,
which may or may not be combined. This also includes the use of acid to etch
out the surface and thereby increase the surface pore volume and improve future
adhesion. Mechanical pretreatment refers to sanding, cutting or roughing up the
surface in order to remove the contaminated or weaker top layer of substrate.
Various methods are available for achieving this including sanding, very
high-pressure water jetting, grit blasting (dry) and sandblasting (wet).
10.3 Concrete floors
For new concrete floors, a laitance layer may be present on the surface,
which will then have to be removed with the help of a light blasting procedure
(particle-free) or the use of a cement remover or special acid cleaning agents.
Depending upon the type of finish desired, monolithic concrete with a closed
hardened top layer must be roughened up lightly to facilitate adhesion of the
coating system. All the preliminary treatment methods mentioned above may be
used for all old and contaminated or damaged concrete floors, in which case the
specific method chosen will determine the thickness of the surface layer lost.
Cracks in the floor can be caused by all kinds of factors and must be
investigated further to determine, for example, whether it is necessary to
consider measures such as injections , dilatations etc..
10.4 Finish
When selecting the type and thickness of coating system to be used for
finishing a floor, several important criteria must be considered:
What loads will the system be subjected to?
What are the aesthetic requirements?
What is the desired degree of roughness?
Which type of substrate must be finished?
Chemical loading factors determine the type of synthetic coating chosen
and minimum coating thickness. Mechanical as well as thermal loading factors
determine the required thickness as well as the hardness of the system in
combination with the substrate.
Since many binders are available which may also be used in combination
with each other, the range of possibilities is practically unlimited.
Solvent-based coatings, low-solvent coatings, solvent-free coatings,
water-based coatings, self-spreading application coatings, impregnating agents
etc. are all available. Products are also available which depends upon physical
properties for drying.
All the above types of coatings differ greatly from each other in terms
of their application requirements and possibilities as well as their chemical
and mechanical properties. However, they all have one thing in common: a chemical
reaction is almost always needed to produce the required end product. Usually,
this reaction must take place at the building/construction site, which is also
why many of these products are supplied as multi-component systems.
A great many different colour options are available for finishing layers
which are not subject to loss of gloss or discolouration and which are also
very durable and scratch-resistant. The degree of roughness can also be
adjusted by mixing in wear-resistant minerals etc. or by including anti-slip
agents in the (thin) top layer.
10.5 Epoxy (EP)
Epoxy-based mediums are made with epoxy resins and amine curing agents.
The standard formulations generally display good properties in terms of
toughness, chemical resistant and wear resistance, and they also adhere quite
well to most mineral substrates. When used outdoors, loss of gloss sometimes
occurs. With regard to reaction/curing times, one should also take into account
that a great deal of heat can be generated in the process, leading to shrinkage
related problems in thicker layers. Adhesion to other types of substrates is
also often amazingly good, which is why these products can be used as both
primer and top coating. Some persons are sensitive to certain types of epoxy
compounds, leading to a bothersome type of skin irritation. This can often be
prevented via a proper choice of binder and the avoidance of specific reactive
thinners and solvents. Proper hygiene during application is therefore also very
important.
10.6 Polyurethane
(PU)
Polyurethanes
are made from polyols and isocyanates. Due to the large variety of polyols, curing
agents and additives available, the range of possibilities is much greater than
with epoxy compounds. Adhesion to various substrates is often excellent.
Polyurethane is an excellent option for finishing off concrete floors. Coatings
can be realized which combine excellent chemical resistance with colour
fastness, weather and wind resistance, wear resistance, and a matt as well as
glossy appearance. Reaction times can be modified with the help of various
compounds. Problems during application caused by allergic reactions are less
frequent than with epoxy compounds, but the instructions with regard to
ventilation and hygiene must be strictly complied with for these compounds as
well.
