To commercial and residential building owners, water damage from interior leaks is an out-of-sight, out-of-mind problem until they see evidence such as a water spot on a ceiling. For the flooring contractor that failed to seal openings in the subfloor around plumbing fixtures, for example, the damage is also out of sight and out of mind—until they hear from an angry building owner with an immediate callback demand.

The costs of such damage are significant, yet easily preventable with the use of a high-performance liquid-applied waterproofing membrane.

The costs are staggering

A look at the costs of repairing the damage, on both the individual case level and in the aggregate, quickly thrusts this problem into sight and mind. Often, insurance will not cover these costs without a policy rider.

  • The annual cost of residential water damage and remediation in the United States is $13 billion, according to 
  • Losses are even higher on the commercial side—more than $16 billion in the United States annually, according to NU Property & Casualty Group.
  • The second most common category of home insurance claims in 2017 was non-weather water damage (19%), behind only wind damage (25 percent), says
  • The average home insurance claim for water damage is $10,234, 

The volume of water and time, i.e., how long the leak existed prior to discovery, are major cost variables. The costs tend to multiply over time as physical damage worsens and mold or air quality problems develop.

The flooring contractor will eventually feel the impact of lower profit margins on projects thought to be completed right the first time, delays in getting new projects started—and reputational damage.

Liquid-applied Membranes Offer Advantages

Using sheet waterproofing membranes is one method for protecting tile substrate against damage from interior water ingress. These membranes consist of plastic or elastomeric sheets that require bonding to the substrate before tile installation occurs. Some sheets have adhesive backing and others require separate adhesives or cement mortar for bonding to the substrate.

The use of sheet membranes invariably involves considerable labor, time and cost because the contractor has to handle several components—membrane, preformed corners, bonding mortar, primer and sealant—and cut the sheets to the right size.

Liquid-applied waterproofing membranes are a more effective alternative to sheet membranes—particularly for ‘wet’ installations such as pools, showers, fountains and spas that must withstand repeated exposure to moisture. Adherence to ANSI A118.10, American National Standard Specifications for Load Bearing, Bonded, Waterproof Membranes for Thin-set Ceramic Tile and Dimension Stone Installation, ensures waterproofing effectiveness, adhesion, dry and wet strength, dimensional stability, and fungal resistance.

This category of waterproofing membrane is composed of liquid rubber emulsion polymers that form a thin, monolithic, flexible, load-bearing, waterproof layer under the tile surface that protects the substrate from positive hydrostatic pressure. The layer cures to a tough, seamless film that resists softening at high temperatures and brittleness at low temperatures. In their cured state, they provide high water resistance and low moisture vapor permeability. They can dramatically increase the durability and life of any interior or exterior tile installation that’s subject to water exposure and positive hydrostatic pressure.

The contractor doesn’t have to use primers, treat seams or account for transitions up walls and through corners when applying these membranes.

Versatility is another advantage of waterproof membranes:

  • They offer excellent adhesion to a wide range of surfaces including concrete, masonry, plywood, gypsum, ceramic, steel, existing Vinyl Composition Tile (VCT) and various plastics. The contractor can apply a waterproof membrane to these substrates before applying mortar to ensure bonding of tile to the membrane.
  • With their excellent elongation properties, most waterproofing membranes also provide protection from in-plane cracks telegraphing to the tile as specified in ANSI A118.12.

High-performance Membranes Offer Protection & Functionality

Not all liquid-applied waterproofing membranes perform equally. The best high-performance membranes exceed the ANSI A118.10 standard and can offer contractors and owners greater protection and functionality in the following ways:

  • High-performance membranes have relatively high wet bonding strength to cement mortar. A118.10 seven-day water immersion testing reveals a typical difference of roughly 25 percent to 40%.
  • The contractor can apply them over new or ‘green’ concrete—as little as three days old. In contrast, a standard membrane typically needs to be in place for 28 days.
  • Another measure of their fast-track properties is the fact that the contractor can apply them on concrete with up to 90 percent relative humidity, due to their high alkalinity resistance. The typical concrete RH limit for standard membranes is 75 percent to 85 percent.
  • Once the high-performance membrane is in place, tile installation can begin in just two to three hours.
  • Thanks to their high cohesive strength, they don’t require mesh installation prior to application.
  • They provide up to 60 percent greater elasticity, enabling them to bridge ¼-inch cracks and saw-cut concrete control joints. In contrast, standard membranes’ crack-bridging capability is limited to 1/8 inch.
  • Although two coats are needed for waterproofing applications, their relatively high elasticity enables them to isolate 1/4-inch cracks with a single coat at 25 mils wet. By comparison, standard membranes require two coats for 1/8-inch crack isolation. By using less material and time, the contractor saves the owner money.
  • These high-performance properties justify longer limited warranties for waterproofing, crack isolation and the overall product than standard membranes typically offer.

Choose Carefully

Make sure to carefully select a liquid-applied membrane and follow the manufacturer’s instructions to ensure reliable waterproofing of tile substrates—and prevent costly failures and callbacks. In general:

  • Application surfaces must be free from oil, grease, dust, paint, sealers or curing compounds.
  • Make sure new concrete is finished with a steel trowel and has a fine broom finish prior to membrane application.
  • After substrate preparation, remove all dust by vacuuming, cleaning the surface with a wet sponge and letting it dry before applying the membrane.
  • Apply the waterproofing membrane in two coats at the correct wet thickness, making sure no voids or pinholes develop.

To give you peace of mind, look for a manufacturer that can train you on how to use their product.

Liquid-applied membranes are your best defense against water damage to tile installations in which water leaks originate inside buildings. Choose a high-performance material that enables you to offer the owner greater protection at a lower cost—and get the training you need to get the most out of your material and labor. Only then will water damage be safely out of sight and out of mind.