sealer performance

Translating Manufacturers claims of sealer performance

Nearly all sealer manufacturers use the same criteria for describing the performance characteristics of sealers. However there is a huge difference between how these characteristics are portrayed. For example all sealers are described as having some degree of stain resistance, but from here some manufacturers say or infer that their sealers are stain proof! So I thought it prudent to look at these common performance claims, strip away the marketing, and translate exactly what these mean in true terms.

The following are the main performance characteristics and claims used by manufacturers to describe sealer performance:

  1. Sealers are Stain proof! This is the most extreme claim made by some manufacturers regarding their sealers. Most do not make such a claim thankfully. However most do not define exactly how well they do seal. The truth is that all sealers on the market today will eventually fail. They are not stain proof! Sealers work by affording the sealed surface some reaction time to remove any offending contaminant. Without a sealer a contaminant is working its way into a porous product immediately. A sealer however increases the time it takes for the contaminant to enter, thus giving you time to remove it without damage. A premium sealer offers the longest reaction time not a stain proof impenetrable barrier!
  2. The Sealer will last 15 years! Claims of longevity are numerous in the marketplace. Most make you believe the sealer will last this time regardless of what it is used on or where. However the truth is far from this. How long a sealer will last is totally dependent on several things.  Firstly the physical characteristics of the stone or tile. For example the surface of sandstone is softer than granite and will obviously wear away faster especially if installed underfoot. Moreover the thermal and moisture expansion of the two products is different. When a penetrating sealer is applied to both of these products in the same underfoot installation it is obvious that the sealer will not last as long on the softer sandstone compared to the granite. The softer sandstone surface is abraded faster along with the sealer, and its increased expansion increases the shear force on the sealer also reducing its lifespan. So claims of longevity must be made relative to the physical characteristics of the sealed surface and the surfaces use and environment.
  3. Sealer coverage. Sealer coverage is often exaggerated to make the overall cost of product look less expansive. However many manufacturers do put a range of coverage (from low to high) which can also confuse customers. The truth is that coverage will change, sometimes dramatically, depending on the porosity and texture of the sealed surface. For example sandstone will consume more sealer than granite. Temperature and other climatic and job site conditions can also affect coverage. So make sure when you are comparing the cost of different sealers you calculate the coverage based on the type of stone or tile you are sealing.
  4. Sealers are Waterproof! This is another claim that is often made – in the main it is not so much printed or written but instead inferred by some companies. Photos of extreme water beading are used to give this perception of waterproofing. Sealers are not waterproof! Sealers used in the industry are not designed to be continuous membranes. They cannot fill cracks and holes in surfaces and hence cannot be considered water tight surface coatings. Good sealers are also designed to allow water vapour transmission something that is not desirable in a critical primary waterproof membrane. Photos of water beading on the sealed surface are due to the low surface tension a good sealer affords the stone or tile surface which in turn allows the water to retain its high surface tension and bead. Lightly scrub the surface and you will see the water beads relax, dampen out the stone or tile surface and slowly penetrate. So DO NOT purchase sealers used for stone and tile if you require the services of a waterproof membrane.
  5. Sealers stop efflorescence! This is another false claim. The truth is that sealers by reducing the ingress of water also reduce the amount and rate of the catalyst water that creates the reaction. So sealers are most certainly a critical part in controlling and managing efflorescence, but they do not and cannot STOP it.
  6. Sealers Stop Mildew! This is another claim that is not true. As is the case with efflorescence water is required for the formation and sustained growth of mildew and other bacteria. Therefore anything that reduces water ingress and helps to keep the surface in a drier condition will obviously reduce the risk of bacteria formation. Sealers work very well in this way, but you will certainly be disappointed if you expect them to STOP bacteria.
  7. Safe Sealers: Many companies call their particular sealers safe. This is one claim that is open to very wide interpretation. The reference point for a safe chemical varies from country to country. For example Methylene Chloride is banned for use in manufacturing in some countries such as the USA but not in Australia . This points to a major difference in that in the USA for example the finished product is heavily regulated at Government level greatly reducing the chance of getting unsafe products into the market.  In other countries where the Government regulatory regime is more relaxed the chance is much higher. The term “safe” is also often massaged by manufacturers who work under more relaxed regulatory systems. For example I was looking at a MSDS sheet (Material Safety Data Sheet) of a sealer where the sealers solvent flashpoint was listed as “NOT AVAILABLE”. Yet later on in the directions for exposure to flame it said “do not expose to flame as solvent is highly flammable”.  These two contradictory statements are only possible under systems that have great flexibility in their regulatory environment. The bottom line is that all safety information should be available for a sealer. If it is not or you are unsure ask the manufacturer and if they are not forthcoming with the information be very cautious about selecting such a product.
  8. Penetrating Sealers that offer surface protection! This is a relatively new type of claim. Penetrating sealers by their nature and definition are sealers that work below the surface. They are not coatings. They are by far the most common sealers used for sealing tile and stone. Working below the surface they are protected against forces such as abrasion that work directly on the surface. This is one of the reasons why they are preferred as they invariably leave the surface looking natural and have greater longevity. However the downside is that being sub-surface they offer no protection against these direct surface forces such as abrasion. However we are seeing some manufacturers making performance claims about penetrating sealers that can only be achieved by surface coatings. For example claims that a penetrating sealer can protect a polished calcium rich stone such as marble or limestone from surface etching through exposure to acid are simply not possible. When claims like this are made what is being sold is a surface coating. These can be made to look almost invisible which makes them appear the same as a penetrating sealer. However as coatings they will be very susceptible to abrasion and as such should not be sold as a penetrating system as this simply confuses people into thinking they will have the same long life and other characteristics attributed to penetrating sealers.

These are not necessarily all of the performance claims made by sealer manufacturers, but they are in the main the most common. As you can see there is in many cases a great difference between some of the claims and the facts. I strongly recommend my clients to do their own investigation into performance claims before selecting a suitable product. I hope the above will assist you in your search. 


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