Make Striping on Concrete Last Longer
Make Striping on Concrete Last Longer
Concrete presents a few unique challenges over asphalt to assure a long life for your pavement markings.
Traffic paint technology has come a very long way in the past few years. BlueSky prefers Latex based paints for concrete surfaces. Alkyd paints (oil based) will work, but they are not as effective and their fumes can be noxious to the public. This especially holds true in parking garages where the air exchange rate may be less adequate compared to an outdoor parking lot. BlueSky has had great success with the newer Liquid Thermoplastic paints on the market. They are thicker and more durable, as well as they provide a high level of reflectivity for lowlight conditions. While it is initially more expensive, we have found it to be highly durable and cost effective over the long term.
If you had to focus on one single factor to assure a long vibrant life of your paint, we would always recommend detailed and deliberate preparation. This holds true for both new concrete and existing well aged concrete, though the areas of focus differ slightly.
New concrete should be simple. It is fresh, clean and ready for paint, right?
Not necessarily true. New concrete, while fresh and typically free from oils, contaminants and the like, does present its own unique set of requirements.
- Let it cure: Brand new concrete has a very high pH. Paint will not adhere to a surface with a pH higher than 10, and most concrete cures at a pH of 13. Typically, after a 30 day curing period, you should be good ready for paint.
- Curing compounds: Today there are a plethora of different curing compounds used on concrete projects. While these compounds do help increase overall strength, reduce shrinkage and cracking during the curing process, and help form a protective membrane over the new surface, this membrane is no friend to paint. BlueSky has seen concrete curb that was treated with a curing compound painted without preparation and within 60 days, all the yellow curb was peeling, creating an unsightly mess.
- If you know an area of concrete has to be painted, especially curbs and large areas, it is best to have your concrete contractor eliminate the use of compound in those areas. This small attention to detail will save expense and potential headaches down the road.
- If a curing compound is already utilized, the surface will need to be sand blasted or acid etched to remove the compound and prepare the concrete surface.
- Remove the dust: If a concrete surface has not been cured properly, it can form a “dust” layer. While the paint will cover the dust, it will quickly become evident. While pressure washing or sand blasting may help, there is still a distinct potential for failure. Mechanical scarification is the most effective method to assuring paint adhesion.
- When in doubt, rough it up! Paint likes surfaces with some texture. High gloss, super smooth finishes that can be achieved with today’s technologies are great, but not for paint.
Older Concrete and Re-striping
As with new concrete preparation is key for older well establish concrete surfaces.
- Keep it rough.
- When dealing with re-painting, your new top coat of paint will only be as good as the old paint you are covering. If the old paint is flaking or not adhered well, BlueSky suggests hitting it with a little tough love, a light sand blast or grinding will reward you with a solid long-life new coat of paint.
- Stains need to be treated and removed. Paint will not bond with concrete that has oil, gas or certain chemical stains. The use of an emulsifier may be required for long term deep stains. Emulsifiers penetrate and help “lift” the offending oils out of the concrete surface. As with any cleaning procedure, proper rinsing and drying time should be followed before any paint is placed.
- Some older concrete may be oxidized. BlueSky recommends grinding the older surface away, and if the concrete is heavily oxidized or aged, it may become necessary for longer term repairs prior to a short-term investment in paint. A reputable contractor will be able to recommend the best course of action to assure your new paint lasts a long time.