Paints and resins for floors must be precisely defined, according to the intended use, from the service staircase to the balcony, passing through the parking space of your car.
The family of “floor paints” includes products of very different composition and use, depending on the intended use. Each support is a special case, the quality of its preparation strongly conditions the durability of the system implemented.
A first classification can be made by thickness. The standards define paints and floor resins in three categories, depending on the thickness. “Thin” films, with a maximum thickness of 1 mm, are the most used for private use.
Semi-thick or thick coatings?
“Semi-thick” coatings, whose thickness is between 1 and 3 mm, can also be used for private use, when the support has appearance defects incompatible with a “thin film” type finish.
The so-called “thick” coatings, from 3 to 10 mm, are rather reserved for industrial uses. The composition of the products and systems determines a second selection criterion. There are resin-based products. Acrylic and metacrylic resins should be reserved for common uses and pedestrian traffic, epoxy and polyurethane resins are the only ones really suitable for traffic areas.
Beware of harmful products.
What problem can the application of paints and floor resins pose?
It can pose two problems: the composition of the resins and the presence of formulation solvents. Regarding the composition of the products, acrylic and metacrylic resins do not present any particular constraints.
On the other hand, epoxy, polyurethane and polyester resins are classified as irritants and / or harmful, which can generate skin and / or respiratory allergies.
Are solvents still so dangerous?
Solvents are still present in many products but their concentration and harmfulness have decreased. The most dangerous products, benzene and toluene, are no longer used for these applications. Nevertheless, solvents remain irritating and / or harmful products which must be protected.
How to protect yourself from it?
Depending on the risk associated with the product applied, personnel must be equipped, as appropriate, with single-use suits, respiratory masks adapted to the products used, gloves and glasses.
Depending on the type of site (interior / confined) and the mode of application (manual / mechanical), a ventilation system must be provided, on the one hand to protect against toxic fumes, but also to limit the risks of accumulation of solvent vapors, which may cause explosions. Finally, it is necessary to seek advice from your occupational doctor for the medical follow-up of the exposed employees.
Pedestrian traffic is the simplest to treat, products compatible with this use are generally economical and easy to use.
These are one-component paints, most often made up of acrylic or metacrylic resins. These products, easy to use and generally not very toxic, do not require special protection.
They are suitable for all applications that are not subject to mechanical or chemical constraints: service stairs, balconies, loggias, laundry rooms, even all “pedestrian” areas of garages or car parks. Who can do more can do less. For specific situations: heavy traffic, severe use, risk of degradation … paints based on polyurethane or epoxy resins may also be suitable, in return for a higher cost and specific installation constraints.
Floor paints are products that can be relatively slippery, especially when the floor is damp or wet. Several methods can reduce this slipperiness. The most classic consists in spreading, at cost and with refusal, grains of silica or glass beads.
The excess is removed after drying and the grains are then covered with a top coat. Another method is to look for products that already contain premixed aggregates and which are distributed as the paint is applied.
Some paints or floor resins can exhibit relatively high slippage. The integration of silica or glass micro-beads solves the problem.
Benefits: ease of implementation, reduced drying times, economic products
Limits: reserved for non-traffic areas.
The application of paint or resin intended for vehicular traffic is subject to two constraints, one chemical and the other mechanical.
Chemical reactions
A normal chemical reaction between the tires and the paint can cause the paint film to peel. This effect occurs at the tire / ground contact surface when the vehicle is left stationary for a long time in one place.
This phenomenon is practically systematic with acrylic and metacrylic paints, but it can also occur with epoxies and polyurethanes, when the adhesion to the support is insufficient. The second constraint is mechanical.
The power steering systems subject the floor paints to very high shear forces, because the drivers turn the wheels on the spot. All of these parameters involve choosing paints or resins suitable for this use: epoxy or polyurethane resins, with or without mineral fillers depending on the flatness of the ground.
Epoxy resins
The best epoxy resins have for them to be very hard and very adherent to the support, the polyurethane resins are more flexible, the setting is faster.
Technically, there is a development of two-component systems, first initiated by manufacturers of epoxy resins and followed since by polyurethane resins. These products, which contain less and less solvents, are less harmful to the applicator, but require, on the other hand, a certain technicality, we do not improvise applicator of resins.
They also impose a minimum temperature at the level of the treated soil, around 10 ° C, which can cause difficulties in winter on unheated sites.
Interests: very resistant products; compatible with vehicle traffic and parking. Limits: technical implementation; cost of supply; environmental constraints for certain products.
The application of paint or floor resin over an old substrate should be given a lot of care. An existing floor is always more or less clogged with dust, traces of oil or corrosive products.
The problem is exacerbated when the room was previously used for “mechanical” activities.
Depending on the extent of the fouling, the surface to be treated but also the future use, several approaches are possible. The safest method, especially for a garage floor, is to perform shot blasting of the surface.
This operation remains economical for large areas, it is proportionately more expensive for smaller areas, since companies specializing in shot blasting often apply flat rates which penalize small areas.
When the room is only intended for pedestrian use, deep cleaning: detergent, high-pressure machine, cleaning, ginning of the old paint… depending on the case, may be enough to guarantee the staying power of the paint coating, subject also the prior application of a suitable primer.
The support
Whoever says old support also often says “cracks”. The general principle is to open them manually or ideally using a grinder, then fill the cavity with a mortar. It will most often be composed of mineral fillers and resins, identical to those used to cover the ground.
When the application concerns living rooms, only a quality preparation can achieve the desired surface appearance.
New screeds: pay attention to the preparation
Above all, you shouldn’t trust the appealing appearance of new concrete. Even perfectly dry and clean, it is not always able to receive paint or resin, everything depends on its porosity.
Depending on the method and the materials used to make the concrete floor, usually a screed, the surface can be relatively closed, or even almost “frozen”.
This scenario is particularly true with screeds made with a “helicopter”. In these conditions, it is necessary to make a shot peening, the only way to “break” the too closed surface film. Shot blasting will reveal a more porous area, which will “hang” more securely with the paint or resin film.
DTU 59.3 gives all the necessary information to define the standard absorption of concrete. The second point to watch to avoid loosening of the coating is the humidity of the screed, which should ideally be less than 3%.
Only the use of a carbide bomb, commonly used by parquet, laminate and plastic coaters, can accurately measure the residual moisture level of the screed.
