Every flooring project is unique, with parameters requiring creative thinking, the proper tools and the right products that reflect your commitment to professional craftsmanship. Because there are so many different flooring installation situations that you might face, specialty underlayments play a prominent role in helping you to successfully meet the challenges. For instance, you might need to build up an elevation, create a slope or perform a patch repair. You may find it necessary to complete a project by a specified deadline. Or the installation may require a waterproofing membrane or a crack isolation membrane. It may be something as basic as finding a product that provides maximum adhesion. In every case, there are products out there that can simplify your life and increase your potential for profits.

Whatever underlayment you decide to choose, you normally assess it based on the following criteria: required minimum and maximum thickness, how much load will it bear, what type of thin-set or adhesive will be used, length of curing time and any unique peculiarities of your project. With builders and homeowners using everything from granite to manufactured stones, vinyls, laminate and hardwoods, selecting the right underlayment can often be an art in itself. So let's take a look at your options.

U.S. Gypsum's Levelrock® is an advanced poured gypsum underlayment offering a harder, stronger surface while maintaining the product's unique benefits and cost efficiency.

Working with poured gypsum sub-floors

The use of poured gypsum as a sub-floor is becoming increasingly popular in the rapidly expanding multi-unit residential market. Its low cost-approximately one-fifth that of cementitious underlayments-light weight, fire-resistant and sound-deadening properties make it an ideal choice for today's building specifier. With radiant heating gaining popularity, poured gypsum provides a perfect flooring medium for these types of systems, as well. But poured gypsum calls for some unique procedures by the flooring installer. For example, waterproofing in wet areas such as kitchens, bathrooms and laundry areas. The TCA recommends that tile installations over poured gypsum utilize a crack isolation membrane or a waterproofing membrane. For additional information reference the TCA Handbook (F-180 and F-200 methods).

New technology is creating a harder, stronger gypsum surface while maintaining the product's unique benefits and cost efficiency, but to avoid job failures, tile installations require the application of a proven ANSI A-118.10 rated crack isolation membrane and, where appropriate, an ANSI A-118.12 rated waterproofing membrane to meet industry standards. Other considerations should be ease of application, curing time and warranty.

Mer-Krete's Fracture-Guard 5000® Crack Isolation Membrane installed over Underlay RS at the Atlanta Airport.

Timing is everything

When you're under a deadline and trying to beat the clock, it's beneficial to use a rapid setting underlayment. They cure very quickly, typically within two to three hours and they can be screeded or troweled on smoothly and easily, You can take many of these products down to a feather edge and they accept various types of adhesives for tile, wood, carpet and more. Typically, a rapid-setting underlayment can be especially advantageous for job sites such as airports, shopping malls and other busy publicly accessed locations where time is often limited by logistics, schedules and a heavy amount of daily foot traffic. If time is not as critical, traditional underlayments offering many of the same advantages, but with a normal drying time, are available at more economical costs.

Mer-Krete's Underlay M®, a two-component underlayment, can be used to build up elevations up to 4 inches thick.

On the level

Many of today's engineered flooring products are thin and may reveal the sub-floor's undesirable surface texture. And there is the added challenge of keeping the surface level and free of cupping which could lead to tile floors cracking and water puddling in low spots.

Self-leveling underlayments can be used effectively to correct where the sub-floor was not laid down to specification, is not level, the elevation set too low, or the original surface is rough or damaged.

Self-leveling products typically cure overnight and exhibit long-lasting performance. Application thickness can range from zero to ¾". Choose a self-leveling product that is easy to install, designed with very good compressive strengths and flexible enough to handle all types of popular flooring. Self-leveling underlayments have proven their worth in virtually all types of construction, from residential to heavy commercial and industrial.

Underlayments must have good bonding characteristics with thin-set mortars for successful tile installations.

Sound advice

One of the trends within the industry these days is the construction of vertical, multi-family units, which is due to the rising cost of housing and the scarcity of land in certain areas.

While this type of residential environment can be affordable and convenient, it also lends itself to noisy surroundings. Since nobody likes to hear the vibration of large floor speakers or the family above practicing the mambo at 2 a.m., there is an increasing need for effective sound-deadening products.

When selecting a sound-deadening mat, keep in mind that it should meet specific LEED (Leadership in Energy and Environmental Design) standards for sound reduction performance and green building technology.

When floors need to support heavy loads such as in auto showrooms, make sure to use an underlayment that is up to the task, like Mer-Krete's Underlay L®.

Weight watchers

If your flooring surfaces require a product that must meet extremely high point loads you need to select an underlayment that is equally up to the task of withstanding a tremendous amount of pressure and weight. An underlayment system such as this should be able to bear the weight of heavy trucks and industrial equipment. Look for an underlayment that is rated Extra Heavy Duty. Generally two part underlayment systems demonstrate greater strength and load bearing capabilities.

In today's fast-paced world of construction, where time frames are shrinking dramatically and costs are being squeezed, it's more important than ever to make sure you install a solid, dependable floor surface protected from moisture, cracks and cosmetic flaws. With very little time and effort you can solve the challenges inherent with floor installations of all kinds. By recognizing which underlayments are most practical for specific incidences, you will do the job right the first time and avoid follow-up work that makes for an unhappy client and a smaller payday for you.