In building, the magic happens when a safe, timely, durable and cost-effective project is delivered by the contractor. And, without a doubt, waterproofing when and where necessary is the most critical component of any finish construction assembly. Without the appropriate materials being specified — and especially if that problem is coupled with a poor-quality, “rushed” installation — this is a recipe for an epic failure of disastrous and very costly proportions. Risking damage, dollars, displacement and health should not be an option on any construction project, let alone one with your firm’s name on it.
Tile installers are all too familiar with what happens in the wall cavity and rooms adjacent to showers and steam showers when they have not been properly waterproofed. Water and steam damage can result in expensive repairs to both the shower or steam shower and the surrounding rooms. The responsibility for water vapor damage has typically fallen on the tile installer, who did everything right based on the information he or she was given.
The Challenges to Success
Above and beyond the obstacle course encountered at any jobsite, there are many additional challenges facing any project that requires waterproofing. These might include limited access to the areas, production schedules with many trades present, and of course, application to the varied sizes and shapes themselves.
Let’s start with schedules. Once access is available, time to complete has more than likely already been cut from the original timing at the beginning of the project due to delays from previous trades, pressuring the tile contractor to complete faster than initially projected. What does this mean? Hurry up and finish, regardless? How can the tile contractor maintain quality, plus uphold codes and standards, all while finding some magical formula to finish faster than originally bid?
Then there are those difficult-to-waterproof, multi-dimensional shapes that have become common for tile and stone installations. Utilizing sheet membranes can be a suitable option in traditional spaces. However, today’s designer-driven wet areas and shower assemblies are often anything but square and flat. These “changes of plane” can definitely be prohibitive to a sheet type membrane and runs risk where change of planes require overlapping accessories and painstaking or bulky folds.
Liquid-Applied Waterproofing Membranes
In both of these cases, a magic bullet does exist: liquid-applied waterproofing membranes (LA-WPM). There are many benefits to these products; the first and easiest to recognize is the ease of application over dissimilar, irregular and varied plane changes in wet areas. LA-WPMs are traditionally much faster to apply than sheet membranes as well. They are as easy as rolling paint versus the more painstaking process of hanging wall paper.
Now that you are entertaining the idea of a LA-WPM on your project, how can we find the magical formula? Changing gears to material selection and the application process may hold the answer. Typical time to apply a liquid membrane with a trowel can be sped up by using a roller method, while the roller method timing can be sped up by moving to an airless spray system. The elastomeric spray rig can cut application time by up to 50%.
Application with an Elastomeric Spray Rig
The concept of airless fluid delivery is very simple: moving the material from the bucket to the substrate as quickly and efficiently as possible. Airless systems eliminate traditional air-powered systems such as compressors and air entrapment into the fluid materials, which can be problematic once applied to the surface. A piston pump cylinder is immersed into the bucket and draws material into the closed pistons. These move up and down to pressurize the LA-WPM into the hose line, forcing the material into a spray tip to apply onto the surfaces to be waterproofed. New technologies in airless spray rigs can deliver the waterproofing membrane at a rate of 2.25 gallons per minute. Some models also allow connection of up to four guns, which keeps larger crews spraying more areas at the same time. Purchasing a suitable, airless spray rig does come with a price tag, however, most equipment rental companies offer a range of elastomeric airless units in multiple locations making it relatively easy to provide on a project. Manufacturers of LA-WPMs should have equipment requirements and recommendations available before you buy or rent machinery. Not all airless sprayers are appropriate for use with elastomeric membranes, as they are more viscous than paint products.
Advantages of Spray Application
Maintaining inventories can be a major challenge on any project and trying to control waste or lost product can be impossible in some cases. While labor is still the largest cost of a project anywhere in the U.S., waste can be a big expense and could make or break a profit margin. Spray-applied applications can substantially reduce product waste as the bucket remains under the immersion pump, and cutting the lid can allow replacement on the bucket and prevention of material lost due to air-cure or evaporation. When a bucket gets low, add a new one under the immersion pump and restart spraying, while taking the small amount left over in the removed bucket and scraping it into the new one.
Can spray applications speed up drying time? When the LA-WPM is pressurized inside the immersion pump and atomized at the tip during application, the liquid applies very consistently over the surface. The first coat is referred to as a tack coat (similar to painting). By the time the tack coat has been applied to an area the size of a shower receptor, the applicator can go back to the starting area and apply the first “build-coat.”
Installing thinner coats of paint will dry faster and the same goes for a LA-WPM. Typically, 60 to 90 minutes after the first build-coat, you can apply the second and final build-coat. In the 60- to 90-minute interim, the applicator can move to another area on the project for spray applications or to another unit. Using the spray method means less down time in between production activities, which allows for significant time savings that are multiplied on large projects.
Faster applications and faster drying times also mean the installation can be flood tested more quickly and expedites the time to tile installation.
Benefits of Liquid-Applied Waterproofing Membranes
Now that we can see the time and labor savings and material waste reduction benefits, how good is this type of membrane itself? Does it meet building codes and American National Standards Institute (ANSI) standards and is it acceptable to use anywhere on the project? Will it help prevent the problems, costs and risks mentioned earlier?
The good news is “yes.” LA-WPMs have been around for years and meet stringent building codes and provide top tier performance attributes. LA-WPMs meet ANSI A118.10 Specification for Load Bearing, Bonded, Waterproof Membranes for Thin-set Ceramic Tile and Dimensional Stone Installation. Some meet the International Association of Plumbing and Mechanical Officials (IAPMO) as approved for use as a shower pan liner over occupied/living spaces.
Other LA-WPMs can now achieve a “low-perm” rating (less than 0.5 perms) as tested by the American Society for Testing and Materials (ASTM) method E96. This rating makes the product suitable for continuous use commercial steam shower applications as outlined in ANSI A118.10. And lastly, some of the LA-WPMs also meet ANSI A118.12 Specification for Crack Isolation Membranes for Thin-set Ceramic Tile and Dimensional Stone Installation. Of course this provides additional protection the finish assembly and confers another benefit for the project owner.
Add it all together and you have the magical formula.