As a professional, you know that the higher temperatures and drier weather of summer in the Salt Lake City region is the prime time for applying roller applied waterproofing materials, almost all of which require a minimum of 40 degrees to cure and cannot be applied over moist substrates.
However, the good weather also means that it is your busiest time of the year for any sort of waterproofing jobs. Especially when the application is to be over an existing concrete surface, proper preparation is the key to a lasting waterproofing solution for your clients.
Contaminated Concrete is a Show Stopper
Unfortunately, no applied waterproofing solution for concrete is truly permanent. Especially in areas exposed to vehicular traffic, contaminated concrete has to be addressed before the application or reapplication of waterproofing material. What are the pros and cons of the various methods of surface prepping contaminated concrete prior to the application of new product?
This is the conventional air blasting of silica sand or slag as media. This is a versatile method that can lightly profile concrete or deep clean it. Abrasive blasting can even remove previously applied coatings. The typical downside is that this method creates a large amount of dust and fractured edging on seams and cracks present in the concrete, and demands a thorough cleaning away of the media and immaculate joint dressing to guard against installation failure.
Shot blasting uses steel as the media to roughen the surface and remove coating and contaminants. Unlike traditional sand blasting, shot blasting equipment uses an enclosed chamber that recovers and separates dust and recycles the steel shot. As shot blasting can still remove prior coatings with a minimum of mess, this is the currently preferred method of concrete deck prep ahead of waterproofing material application.
Truly the quick and dirty method best suited to smaller trouble areas or vertical surfaces. Grinding is performed with either hand-held or walk-behind machines. Using abrading stones or rotating discs under pressure at right angles to the concrete surface, the downside in grinding is possible loss of profile that waterproofing materials require for proper substrate adhesion. If the concrete is too smooth, other surface prep will be required prior to application.
In the next entry we will have an overview of the other three common ways for surface prepping contaminated concrete, scarifying, scabbling, and water jetting.
If your job is imminent, and your knowledge light, contact the Salt Lake City contractor desk today at 801-410-4345 with any waterproofing technical questions you have. All of our technicians have the product and technical knowledge of the products we sell, and we are here to support the building community – whether it is a contractor, builder, or a homeowner!