Why is surface preparation needed?
Concrete surfaces are prepared before laying down a topcoat not only for superficial reasons but also for mechanical reasons. Construction work requires surface preparation prior to installing floor coating in industrial and commercial applications in order to create long-lasting hold and durability. The texture of the existing concrete is an important consideration when laying down floor coating or resurfacing materials.
What is Concrete Surface Profile or CSP?
Concrete overlays and coatings need proper bonding. Construction professionals see to it that the surface has the right concrete surface profile or CSP. The International Concrete Repair institute has developed benchmark guidelines to help contractors. CSP is a measure of average distance from the peaks of the surface to the valleys. The peak ranges from CSP 1 – nearly flat – to CSP 9 – very rough. The ruling states that the thicker the overlay or topping, the higher the CSP should be. To achieve higher ranges the substrate often needs roughening by shotblasting or scarifying.
What are the steps in surface preparation?
Here, contractors and the property owners get together to determine the sope of work. The following needs to be determined:
- work schedule
- clean up process
- safety measures
- acceptable noise levels
The general job specification for surface preparation is that the surface should be “sound, free from surface defects, dry and clean.” It is important that everyone concerned with the general construction work aligns all requisites so there are no expensive errors. Specifications should clearly state how uniform, clean and at what strength the substrate should be prior to a coating or overlay installation.
Survey the current state of the concrete surface
The contractor must conduct an assessment of the concrete surface. The assessment should include a check on the top layer of the cement and whatever needs to be removed from the concrete surface. The surface should also be checked for existing sealers, curing materials, grease, oil or dirt that has to be removed.
Cleaning the concrete surface
Chemicals, oil and grease should be removed from the concrete surface. Everything that is on the surface should be taken off. Chemicals can be removed using high-pressure washing. Oil and grease needs heavy-duty degreasers and scrubbers. Shotblasting and scarifying can be utilized on floors to take a layer off the top.
Roughen or “profile” the surface
The texture or “profile” of the concrete is a very important characteristic to acheive. Depending on the scope of the project, roughening the concrete by mechanical profiling works but for some acid etching is also convenient. Mechanical profiling is usually for large areas of floor coatings in industrial or commercial applications.
Surface defects should be repaired
The contractor, having evaluated everything, should now know what repair materials to have on hand. Chips and protrusions found in the concrete greater than 1/16” should be ground down and refinished to match the rest. Unstable concrete, bubbles and holes should be assessed and filled up with epoxy or other filling agents and refinished to match the rest.
Resurface the concrete
Having done all preparations, the concrete is now ready for resurfacing.
The above is just a simple overview of the techniques used when doing surface preparation. The process is best left to a professional like Champion Coatings who will assess the situation of existing concrete and determine the scope of work to ensure good overlay, bonding, longevity and performance.