SURFACE PREPARATION
most critical elements of the job because it affects everything else. We use a range of different equipment and techniques depending on the environment.
RSL provide access to their Technical experts which are a very useful resource. We’ve been called in as a specialist contractor to rectify enough flooring problems to know that without the correct subfloor preparation you’re simply wasting your time no matter which system you apply.”
Choosing the right method of preparation: There are a number of methods of preparation available to the contractor.
Vacuum Shot Blasting The most widely used is vacuum shot blasting, where steel shot is fired at concrete under a vacuum to remove the debris. Vacuum shot blasting provides an excellent mechanical key, whilst simultaneously removing surface contamination and laitance. The size of the job, the accessibility, and the area available will often determine the suitability of vacuum shot blasting, as the machine itself is large and
bulky and there is the associated vacuum equipment.
This process will leave a texture on the concrete which can sometimes reflect through coatings. This type of finish is often acceptable to the client, if a smoother surface is required then a thicker resin system, such as Resuflor or Resuthane can be applied at depths between 2 and 5 mm.
The use of shot blasting as a preparation for trowel applied screeds such as Resuthane or Resucrete is ideal, as the texture and thickness of the products are such that they cover the profile.
Whilst the method is very good and cost effective on large areas, it can work out to be expensive in small areas.
Diamond Grinding Concrete surfaces can be ground instead of being shot blasting. Diamond grinding can also be used for small areas and is ideal for difficult or cramped areas and for edging.
There are a range of machines available from small hand held, to large multi-head heavy duty machines. Extraction must
be arranged when working with grinding equipment and most machinery has the capability to have this fitted. Depending on the equipment and choice of blocks or tools, varying degrees of abrasion, profile and surface texture can be achieved.
Vonarx & Scabbling
Other methods include Vonarx and Scabbling, both very aggressive techniques which create a ‘ploughed field’ or rough texture effect. A series of tungsten tipped flails spin at high speed and impact on the surface of the concrete to create a very profiled surface, ideal for highly contaminated areas.
Coatings & Coverage Operational factors including the type and severity of trafficking (wheel type and loading), the frequency and efficiency of cleaning, mechanical handling abuse and impact, etc. should be taken into account when determining the specification and thickness of application of a resin finish.
RSL publish practical rates of coverage which are achievable in the vast majority of environments. Contractors who try to use less product, will, despite
the best preparation, fall at the last hurdle, either with a poor finish or poor resistance to wear. Some products such as self-levelling systems require a minimum depth of cover to properly level and provide the most durable system.
Side Effects & Additional Costs In selecting the method of preparation, the contractor must also consider the effect of noise and dust on staff who continue working close by, while the preparation is undertaken. The level and impact can be easily controlled but there are cost and time implications for these controls. Similarly the removal of contamination from a floor surface raise issues about suitable and safe methods of waste disposal, where increasing cost and reducing available sites for disposal make this an growing issue.
The Real Value of Good Preparation Paul Maton, Technical manager at RSL says “There’s no doubt that good surface preparation is critical in achieving a long lasting and high quality resin flooring system. Some Contractors cut corners on preparation without realising how little impact this has on the overall cost and time taken for the job, whilst massively increasing risk of failure. This exposes them to penalties, added costs in terms of reinstatement involving more preparation and more product, and lost profit, and is just not worth it.”
www.resinsurfaces.co.uk
www.tomorrowsflooring.com
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