Avoiding Sealer Problems

In almost every case of sealer failure, the basic fault can be found in one of three areas; surface, surface preparation or application procedure.

The following list addresses the most common problems faced during the preparation process and actual application of the sealer.

Moisture: The most common cause of solvent based sealer problems is moisture remaining in the surface to be sealed. In porous materials such as common brick, Mexican tile, etc., there is room for tremendous quantities of water. In many cases this moisture cannot be seen on the surface. Causes of moisture problems are varied...high water table, hydrostatic pressure from underground water sources, runoff from heavy watering in adjacent areas and the most common water problem...applying a sealer before the cleaning water has had a chance to completely evaporate. These are common problems and in some cases so severe (especially hydrostatic pressure) that it is actually impossible to make any type sealer product work. The main protection against moisture is applying the products to areas that are completely dry. The best way to do this is to verify penetration with a small test area.

In almost all cases, if a solvent based sealer turns white from entrapped moisture, the situation is easily rectified by applying another coat of sealer.

Acid Residue: If an acid/water mixture must be used, make sure to flood the surface with plain water first. This keeps the acid on the surface where it is needed and out of the substrate where it will cause problems. The acid/water mixture should then be applied in some volume, agitated with a stiff broom in severe areas and allowed to remain until it stops fizzing and bubbling...usually on to three minutes. Now the surface must be completely flushed with water. Two or three thorough flushes should be adequate. Never allow the acid to dry on a surface to be sealed. Allow the surface to dry completely and apply sealer. Always do a small test area prior to application.

Detergent Residue: If a surface is cleaned with soap and water, scrubbing and thorough multiple rinses are extremely important to remove all residue. Detergents are emulsions and if allowed to dry on a surface they form a barrier that is impossible for most sealers to penetrate. One simple test to verify the probability of the product penetration and adhesion is to sprinkle drops of water across the surface to be sealed. If the water penetrates and does not bead up, the surface should be ready for sealing.

Efflorescence: The white powder like substance found on many concrete, tile and masonry surfaces is called efflorescence. This is a form of salt which is carried to the surface by moisture. The moisture then evaporates leaving a salt deposit deterioration. This residue can be removed by an acidic cleaner or certain acids. If this residue reappears after cleaning, it may be necessary to repeat the process. Make sure all acid/water is eliminated before applying a sealer. In extreme situations, if the residue continues to appear after repeated cleaning, remove as much as possible with a wire brush.

Hot Weather Application: Neither a water based sealer nor a solvent based lacquer should be applied on an hot day in direct sunlight. During warm weather apply these products in the morning or evening when surfaces are cooler. If it is necessary to apply a sealer during hot weather, a slight amount of water can be lightly sprinkled over the area prior to application of the water based type sealers only.

Cold Weather Application: Water based systems are much more prone to problems during cold or damp weather. Drying time is based on temperature, humidity and air movement. Under extreme conditions it can take up to 24 hours for water based products to dry completely. If it rains, or water is applied to a water based product before it is dry, it creates problems.

Foreign Materials in or on surface to be Sealed: For a sealer to perform it's job it must bond and adhere. For it to bond and adhere it must, to some extent, penetrate Anything that stops this process can cause difficulties. Obviously a sealer should not be applied to a glazed ceramic tile. But, there are many clay products that are factory sealed without an obvious change in surface appearance. There are also a multitude of transparent penetrating sealers that are used on tile and masonry. These products can retard the penetration of a surface sealer. If there is a rule to follow in successful sealer application, It is the testing of a small area for penetration and appearance prior to total application. Silicon caulking and expansion joints must be carefully avoided when applying a solvent based product.

Water Spotting: Some water has a high mineral content. When this water is splashed onto a sealed surface it will evaporate leaving a white residue that looks similar to efflorescence. This residue is easily wiped away but the only permanent solution is a water softener or the removal of the water source onto the treated surface.