Membranes, like the one being  applied here to a by an installer, can help protect against moisture while dampening noise. Despite the long term benefits, many retailers are unfamiliar with the options available for sub-floor prep.

Let’s face it, there’s not a lot of time to learn all the ins and outs of a ceramic tile or stone installation. You are not alone if you figure it’s a topic best left to the pros at the job site.

For example, how familiar are you with the use of anti-fracture and waterproofing membranes? Most installers will tell you they are vital to the longevity of the installation, yet many at the retail level know little about them. And what about the addition of sound control membranes or underlayments? This is a relatively new but important element of a successful install. You might even want to consider this for your operation if you are in close proximity to others. A sound control membrane can be the difference between a harmonious retail environment…and an angry neighbor.

But first let’s start with crack isolation/anti-fracture membranes. Whether it’s a liquid fortified with fabric, a sheet-type material, a trowel applied cement or a latex application membrane, these are indispensable. When applied properly they reduce the potential for minor shrinkage or spider web cracks from reflecting through the tile or stone finish.

While the actual performance of the products may vary slightly, most can suppress cracks up to 1/8” (3mm) wide. These membranes also address only those cracks that are experiencing lateral in-plane movement. Most of these membranes will not suppress cracks that are experiencing vertical (up and down) movement.

Keep in mind that crack isolation membranes (also known as Anti-Fracture Membranes) generally have two main functions. The first is preventative, the other corrective. The protective layer helps prevent shrinkage, spider web cracks and other non-structural cracking. This is important because these cracks may be unseen to the eye prior to the installation, but later telegraph through to the finish layer.

The corrective properties come into play if there is shrinkage or if spider web, hairline or other non-structural cracks already exist in the substrate. The use of a crack suppression/anti-fracture membrane will prevent these underlying defects from compromising the finish. Neglect this aspect of the job and you will regret it when you see the cost of repairing the finish. To treat the visible cracks in a substrate before installation, see the Partial Coverage method, TCNA F125.

Waterproofing Membranes

Waterproofing membranes, which are also available in latex, liquid or sheets protect spaces below and adjacent to a tile or stone application. They are very easy to install and are usually compatible with the thin bed method of tile installation. Many of these membranes also double as anti-fracture membranes. And, by using a waterproofing membrane you will also be in compliance with the Full Coverage Crack Isolation Membrane Method, TCNA F125A. The bottom line is that moisture can be the undoing of a floor.

Sound Control Products

What’s that you say? You are not all that familiar with sound control membranes and other products?  They vary in composition and are very similar to crack isolation and waterproofing membranes. They are mainly designed to reduce the level of noise below the tile or stone installation. More and more retail stores, high-rise apartments, condos and, of course, hotels are insisting these products be used with a tile and stone install. It’s important to know, that the crack isolation and waterproofing membranes provide some levels of sound control, but not enough.

For optimal sound reduction choose a thin, composite underlayment or roller applied liquid as a noise barrier. The sound control properties limit two distinct types of sound: ambient airborne noises like people talking or radio and TV sounds (STC); and  more abrupt noises produced by footsteps, articles being dropped on the floor, the moving of furniture or any other direct impact to the floor (IIC).

(For more information on sound rated floors, refer to the TCNA Handbook.)

One Final Note

No matter what type of membrane is used, do yourself a huge favor and consult with the manufacturer of the product to determine the right adhesive mortars or grout to be used. Manufacturers usually provide a comprehensive labor and materials warranty for systems that include their membranes-but only if you go by the book.

Also, many of the same industry standards apply to the use of the membranes as they would to the direct bond method of tile installations. This includes deflection standards, substrate preparation and expansion joint placement, just to mention a few.

As an added benefit look for a membrane with anti-microbial agents designed to reduce mold and mildew growth. These products frequently are also low volatile organic compound (VOC) emitting and help protect the indoor air quality. This in turns is a contributing factor to gaining LEED Certification.