Craig Powell, technical manager at Kelmore, discusses the benefits of priming.
To use a boxing analogy, priming certainly punches above its weight. Serving numerous functions, this quick and simple process really could be a contender for the “pound for pound” champion due to its positive impact when tile fixing or levelling and smoothing. In a world where most of us like things to be made as simple and easy as possible, people are searching for a “one size fits all” solution to many things.
However, when it comes to primers, we at Kelmore believe that to get the best results, primers should have specific functions, whilst not compromising on a simplistic, easy and efficient approach to their instructions and use. At Kelmore, we have three primers in the PrimeMore range: Universal, Grip, and CS.
PrimeMore Universal is for use on porous backgrounds, is always diluted 1:3 with clean water, and plays the important role of controlling background porosity. Unprimed or insufficiently primed porous backgrounds can prematurely suck moisture from cementitious products. This not only decreases working times, and affects the surface finish of levelling and smoothing compounds but can also decrease the product’s performance. As cement gains strength through hydration, if water is lost too quickly, hydration can be incomplete, resulting in insufficient development of strength and durability.
PrimeMore Grip is ready to use and is designed for use on non-porous backgrounds and plays the important role of enhancing the bond of products to backgrounds with no porosity. Smooth, non-porous backgrounds can be difficult to adhere to as there is no suction or surface texture to facilitate this. A bond promoting primer, such as PrimeMore Grip, dries with a textured, keyed surface that enables strong adhesion of subsequently applied products.
The third primer in the Kelmore range is PrimeMore CS. This ready-to-use primer is specifically designed for use on calcium sulphate/anhydrite screeds. These screeds can sometimes be perceived to be problematic as many over the years have been tiled without being sufficiently prepared and as a result have failed. With all calcium sulphate screeds there are preparation steps that must be undertaken. Laitance, a weak layer created when fine particles float to the surface during curing, must be completely removed. If the screed is heated, then the underfloor heating must be commissioned, and the screed must then be moisture tested and confirmed sufficiently dry at 75% relative humidity (RH). Finally, the screed must be primed sufficiently, which often requires numerous diluted and undiluted coats.
When developing PrimeMore CS, we looked to address some of the common issues associated with calcium sulphate screeds: moisture levels delaying the start of work and adverse reactions between applied cementitious products and the screed. So, when all the standard preparation procedures mentioned in the paragraph above have been undertaken and a moisture reading of 85% RH or less is confirmed, PrimeMore CS can be applied as a neat, single coat. This quick drying primer is pigmented a vibrant red which enhances visibility and facilitates total and uniform coverage of the background, and by penetrating and sealing the screed’s surface, any adverse reaction with subsequently applied cementitious products is eliminated. Regardless of your choice of primer, and to continue the boxing analogy, the key takeaway is to avoid taking a hit to your business by neglecting the priming process.
www.kelmore.co.uk
