So Which Concrete Paint is Right for Me?
Painting concrete comes with it’s own set of challenges compared to the painting most of us are used to. Concrete can have varying degrees of humidity, alkaline bloom (sometimes called surface laitance especially on new concrete where the lime in the mix has floated to the surface), oil and grease contamination on older floors not to mention the porosity can mean that water from below can by pushed up through the concrete by hydraulic pressure when the water table rises. Older concrete can also be contaminated with algae or other forms of biological growth hence the term often found when talking about old concrete referred to as “green” concrete. All of these challenges can be overcome with a little careful planning and good surface preparation and
choice of the right product for the job. This is a job for specially formulated Concrete Floor Paint.
Preparation is Key
Concrete Paint requires good surface preparation prior to use for the best results followed by the right product from the range of Concrete Floor Paints available for your needs. To get a good result the surface should be cleaned down well using
clean and degrease and allowed to dry thoroughly. Surface preparation is time well spent on concrete even more than any other substrate.
The "Right" Paint Choice Depends on the Floor Use
Having cleaned and dried your concrete floor it requires some careful thought as to the intended use of concrete floor
once the floor has been painted. Tackling the key reasons why the floor needed to be painted determines the best Concrete Floor Paint to use. These include suppressing the dust, covering up tyre or paint or oil spillage marks, wanting to improve the anti-slip properties of the concrete as (particularly with power floated concrete) the original concrete is slippery when wet after the car has been garaged after being out in the rain. It could even be that if space is tight you feel painting the space on the floor, your own “parking bay” makes it easier to make the best use of the garage or allocated parking and of course sometimes for aesthetic reasons you want to paint over the old micro cracks and discolouration on the floor by using suitable concrete
garage floor paint.
Concrete Floor Paint comes in a range of colours and types suitable for the different used. Usually, especially on older floors but old oil residues and other contaminants favour the use of a solvent based or solvent free
floor paint. This is because water based paints tend to give poor adhesion to oil or dirt and have what is known as a “minimum film forming temperature” below which they don’t paint out and dry well. For a floor this is usually above 20 degrees for products with good wear characteristics and the only other solution is to add solvent to overcome this and reduce this minimum film forming temperature. It is also a problem in the UK that high humidity and our high rainfall make water based paints more problematic as they don’t dry well in a wet humid atmosphere
which can lead to premature failure and
paint coming off onto the tyres of the car, for example. Concrete Floor Paint is available with a range of product types to suit the UK climate and drying conditions.
Some Advice on Using Single Pack Paint
For most consumers, a light duty Concrete
Floor Paint used by modern paint producers formulated as a single pack product based on resins derived from renewable resources are favoured. These “modified alkyd” resins can include a higher than normal anhydride content or chain stopping agent to reduce mechanical damage (scratching) and blocking (also known as pick up for dirt). Polyurethane modification is also possible to improve toughness and the use of solvents with lower odour (so called dearomatized solvents)
and these are also popular as Concrete Floor Paints for large light duty warehouses which have to be back in operation quickly – sometimes in as little as a single shift since they are easy to apply, have no pot life and can be applied by the workers without employing specialist labour using a brush or roller. Spray painting is possible but usually this is not used as the wastage factor is higher than by roller (by around 20%) which for large areas can be significant. Concrete Paint also has advantages in high use areas where touch in repainting saves repeating the whole job since they have few overcoating or repainting issues. This also makes them ideal for consumer use and they are available as a quick drying or standard type depending on the time available to first use. However, it is good practice to
allow a newly painted concrete floors to dry through thoroughly for a few days before driving on it with rubber tyres (the twisting action of turning the wheels to change direction can act like a suction cup and pull away patches of paint where the tyre was standing). This is often caused by solvent trapped under the dry surface of the Concrete Paint which can take little longer to disappear even from an apparently dry hard surface. For this reason two thin coats give a better end result than a single thick coat with these modified alkyd types, the first coat to prime and seal the concrete and the second coat to give the finish. This is particularly true if the paint has been allowed to “pool” and become thicker than the rest, for example where a small indentation in the concrete has allowed the paint to “settle”.
Concrete Paint Formulation
Concrete Floor Paint is carefully formulated to carry out specific functions. Concrete floors, usually contains lime as part of the mix. Concrete Floor Paint is formulated to avoid saponification (alkali hydrolysis) particularly on new or untreated concrete where the white lime (surface laitance) can be clearly seen where the lime has floated to the top removing this surface laitance greatly improves the life of the coating and whilst professionals usually do this with a mild acid etc for consumer use this is not always practical so a good cleaning with
clean and degrease can go a long way to improving the results. Concrete Floor Paint also has to have good wear resistance and flow so that brush and roller marks disappear but also to allow the wear resistance to develop and on anti skid coatings the additives to “bind” into the coating. This is why it is always a good idea to follow the manufacturers recommendations especially concerning preparation and priming the concrete.
When to Use Two-Pack Epoxy
Concrete Floor Paints based as mentioned previously on “modified alkyd” technology from renewable plant raw materials are good general purpose products. However,
heavy duty use or longer maintenance cycles require a thermoset resin technology. The best thermoset resin for Concrete Floor Paint uses epoxy resin. Solvent or solvent free
Epoxy Floor Paints are not as easy to use and overcoat as their
single pack brothers but offer longer life, improved chemical and wear resistance. They are also more expensive, comprise 2 or sometimes 3 components which must be mixed prior to use and can’t be used once the pot life is over. This means that for people working alone doing a domestic type concrete floor you have to finish the job in a few hours or carefully weight out of each component only as much as you can use in the pot life. This can be an extra complication which many consumers don’t feel comfortable with whereas with an alkyd, you can stop at any time, reseal the tin and finish it later – perhaps after lunch? Overcoating is also more difficult with
Epoxy Resin Floor Paint as it is formulated to resist abrasion so sanding previous coats to improve adhesion can take time without specialist mechanical sanders for floors. These are available and can be hired but most consumers prefer a simpler solution and just to repaint every 2 – 3 years or the ability to patch in marks and damage easily.
In Summary
To summarise, Concrete Floor Paint gives good results but choice of technology is dependent on what use you will put the floor too. Concrete
Paint can give a good professional result even in the hands of
novice with a little attention to surface preparation and choice of Floor Paint. You should always follow the manufacturers application instructions.
