Embossing levelers, introduced in the mid 1980s, rank as one of the most significant advancements in flooring installation. They made it possible to install over most existing resilient materials without using underlayment, cutting doors or raising floor’s height. Embossing levelers also eliminate labor intensive floor removal and the concerns with floor removal methods.
When using embossing levelers it is important to use them correctly. The following six guidelines are critical to a successful installation:
Requirements1. There should be no more than one layer of resilient flooring existing. If there are more layers they should either be removed or covered with an approved underlayment board.
2. The existing resilient floor material must be completely and firmly bonded. Any loose spots or loose seams should be either cut out and filled with Portland-based filler or re-cemented with the proper flooring adhesive. Remember when an adhesive dries it creates a shrinkage, which will create a stress on the old adhesive, so a good bond is important.
3. The existing resilient material must be free of any residuals. Waxes and polishes can work as a bond breaker, affecting the final installation. Any residuals can be removed with a commercial floor stripper and rinsed, thoroughly.
4. There should be no signs of moisture damage or alkali. It would be futile to install over a moisture, alkali or dry rot problem.
5. Do not install over an existing cushioned-backed material. Nothing should be installed over a cushion-backed resilient material including any type of underlayment board.
6. Do not use the embossing leveler as a filler to fill areas of repair. They generally shrink too much and take too long to dry in the thickness required for filling a damaged area.
With so many types of finishes that are on the surfaces of existing materials, it is necessary to determine the surfaces which are difficult to bond to. These surfaces range from silicones, Teflons and acrylics to polyurethanes. These were applied to the surfaces of old materials to create a low maintenance product and can be difficult to bond to. There is a simple test to make that determination. Take a permanent felt tipped marker and place a small mark on the surface of the material and try to remove with a solvent such as lacquer thinner. If the mark comes off it is a difficult surface to bond to.
While there are some one-component embossing levelers most of them must be mixed. Mixing of the embossing leveler must be done carefully. Some embossing levelers require an additive for both bond strength and flexural strength. Flexural strength is very important in an embossing leveler, because of the flexing of the leveler sandwiched between two pieces of material.
The biggest problem with these products is adding too much water or additive. The addition of excessive liquid will cause more shrinkage and may require another coat. It will also create a softening and dusting of the leveler, leaving it poorly bonded to the existing material.
When using an embossing leveler it is important to use a trowel that is in good shape. Inspect your trowel to be sure there are no turned-up ends (warpage) in the trowel. Trowels with a turned-up ends will leave ribbon-like swirls that may show through the material. Next the corners on one side of the trowel need to be slightly rounded. (see Photo 3) This rounded edge will prevent the small ridge that is left by a square edged trowel.
When applying the embossing leveler keep the trowel at about a 45 – 60 degree angle and keep the application at a diagonal to the pattern being embossed. This will prevent the trowel from dropping into the grout lines or pattern. Also do not use too much downward force on the trowel; it can cause the trowel to scoop out the leveler.
The drying times can vary depending on temperature and humidity and from one embossing leveler to another depending upon the type of additive used. Do not use a fan directed directly onto the completed coating to speed up the drying. If you are going to use a fan direct the airflow to the ceiling and let the air move throughout the area. Drying too fast causes accelerated shrinkage, which can affect the quality of the bond to the material being leveled.
Materials with heavy embossing usually need a second coat. Embossing levelers tend to shrink when they dry and when applied over a heavy embossed material the shrinkage will show through the finished floor, especially in low level light and materials with minimal embossing is to be installed.
Precautions that must be taken when using embossing levelers:
·They must be completely dry before the material can be installed.
·Any unevenness left be the trowel application can be either scraped off with a sharp scraper or smoothed with a sanding block.
·Because the dried embossing lever is water starved, when dry it will cause water-based adhesives to lose about half of their working their working time.
·Some adhesives will re-emulsify the binder in the embossing leveler. So open times of an adhesive must be monitored.
·Regardless of embossing leveler used check the flooring manufacturer’s warranty.
·Do not use for commercial application or where heavy traffic is anticipated. Embossing levelers cannot stand up to heavy abuse.