Walk into your local distributor, and you’ll see adhesives running the gamut of price points and flooring types. But what really is the difference between a good, better and best adhesive? We spoke with several adhesives manufacturers to find out how to pair the best adhesive with the right project.
Josh Neuberger, marketing manager of Uzin Utz North America’s Pallmann division, puts it simply: “Generally speaking, all adhesives are designed to do one thing and that is stick. Certain adhesives contain more water or solvents (and are generally cheaper) than urethanes or resins, which also lends to different application processes.”
He said contractors choosing between adhesives need to consider several factors, including the type of material being glued down, any restrictions on the adhesive (“some adhesives designed to handle solid flooring can only handle up to certain widths,” he noted) and the yield of the adhesive versus its cost.
“An adhesive might seem like a good value and come in a large pail, but only be able to cover a small amount of sq. ft. per gallon. At the same time, a similar adhesive that sells for a bit higher price and comes in a smaller pail might seem like it is more expensive at face value, but in reality the sq. ft. coverage is better than the larger pail,” Neuberger stated.
According to Mary Battiste, H.B. Fuller Construction Products’ integrated marketing manager, moisture issues play a big part in choosing the right adhesive. “Moisture vapor often presents a problem, especially for glue-down floors. Typically, premium-priced adhesives are more tolerant of moisture. If you know you will be working on newly poured concrete, you will want to choose an adhesive that can handle high RH (relative humidity) levels.”
Knowing the open time of the adhesive is also important, she noted. “Adhesives with longer open times give the contractor more flexibility between the time the adhesive is applied to when the floor is put down.”
Battiste added, “Knowing the delay between when the floor is put down until when that floor can handle foot traffic can also be important to the contractor. Adhesives and floors that can handle immediate foot traffic will be less prone to rework and failures.”
Kelly Mullen, marketing manager for Premier Building Solutions, said another consideration when choosing an adhesive is its green content, especially when used in places like schools and hospitals. “I would suggest looking at the certifications a product has. For instance, our full line of TerraMax flooring products is GreenGuard Gold certified.”
The newest trend she’s seeing in the adhesives segment is a shift to adhesives that “combine the properties of both urethanes and silicones”—what Mullen calls hybrid technology.
“Hybrid flooring adhesives are gaining popularity in the industry due to their environmentally friendly properties and superior performance,” she explained. “They can be applied anywhere acrylic or urethane adhesives can be applied. They also have little to no odor, excellent adhesion and high solids content, which eliminates shrinking.”
Blair Roberts, Schönox HPS North America’s marketing coordinator, said the substrate also needs to be considered. “Determining whether the substrate is porous or non-porous will definitely help eliminate any unnecessary use or waste. This also determines the preparation needed before applying the adhesive, the moisture resistance level of the adhesive and the drying time. From there, it should be much easier to find the most appropriate adhesive for the job.”
According to Jeff Johnson, business manager for MAPEI’s floor covering installation systems, the type of flooring will drive the chemistry requirements of the adhesive. “For example, vinyl-based flooring material requires acrylic adhesives, while fibrous or paper-backed flooring would need multi-purpose or SBR latex type adhesives. If it is wood, then you should be working with one-component, moisture-cure urethanes or silane-based adhesives.”
The amount of traffic and expected lifespan of the floor will also influence the contractor’s choice on what adhesive to use, he stated. “You can select an adhesive based on its performance values in terms of good-better-best or low-medium-high solids. If the flooring is expected to perform under high-traffic conditions, only the highest performance adhesives should be used. If the flooring has a short lifespan or it will be replaced every other year, adhesives with lower performance values will make tear-out easier.”
Warranty packages may also play a part in the decision, Johnson added. “Some flooring manufacturers have strict warranty programs that enforce a specific adhesive usage with their product. Some adhesive manufacturers offer warranty positions similar to flooring manufacturers, which allows contractors to reduce the number of adhesives in their warehouses as opposed to having to purchase multiple brands of adhesives for specific brands.”
Hardwood flooring adhesives
Heather Lindemann, spokeswoman for Bona, said choosing what adhesive to use in a hardwood flooring installation will often come down to “moisture versus price.”
“Many of the competitively priced products in the market work well up to a specific moisture threshold, which is usually up to 3 lbs. calcium chloride or 75% RH,” she explained. “When these products are used on installations that exceed those limitations, problems will inevitably occur. Understanding the direct correlation between moisture and the dimensional changes that occur in wood lead many experienced flooring companies to look for products that will protect up to 18 lbs. calcium chloride or 95% RH, which is just shy of standing water.”
Cleanability also comes into play, especially when working with prefinished floors. “With the lion’s share of hardwood flooring installations in most markets being prefinished, it becomes an important consideration to avoid having any adhesive residue remain on the surface of the boards,” Lindemann stated.
One application for hardwood that’s growing in popularity is using it on the wall, she added. “We recently spoke with a high-end specialty flooring retailer in NYC who told us that vertical applications now represent about 15% of his total wood flooring sales. Bona anticipated this trend and has developed a higher-tack wood adhesive called Bona R880, launching later this summer.”
Bona R880 is an elastic, silane-based construction adhesive with high initial bonding strength and extremely quick setting ideal for vertical surfaces. The rapid set is designed specifically for repair work at silane-bonded hardwood floors or the installation of trim boards and vertical wood paneling. Bona R880 offers fast installation, is water and solvent free, low in VOCs, adheres to almost all substrates and is easy to remove, she noted.
“One of the unique properties of Bona R880 is that when the product is misted with water, the open time is cut in half and the grab that is achieved requires less pinning for vertical applications. It makes for quick setting, which is ideal for vertical surfaces,” Lindemann added.
Mark Lamanno, flooring technical market manager for Franklin International’s Titebond brand, said that experienced hardwood flooring contractors know to select an adhesive based on the type of floor they are installing.
“Thinner engineered products don’t require as strong of an adhesive as, say, bamboo or solid wood flooring does. These require an adhesive with higher shear strength to restrain movement of the wood, yet allow some movement,” he noted.
Adhesives with multiple features, such as a built-in moisture barrier and sound control properties, are becoming more popular. Lamanno added, “Most wood flooring adhesives these days are urethane-based. Some installers prefer the easier trowelability, quicker green strength and easy cleanup of the advanced polymer-based products (such as Titebond 771-Step Wood Flooring Adhesive). These adhesives, based on silyl modified polymerization, are slowly cutting into the dominance that urethane adhesives have long held. They are easy to trowel and clean, and cure rapidly.”
Whatever product is ultimately chosen, make sure to read the manufacturer’s instructions first. “Trowel choice is critical to installation success,” Lamanno stressed. “Different wood flooring types require varied amounts of adhesive, and the trowel size and notch profile control adhesive amount. Three-in-one adhesive, moisture and sound control systems such as Titebond 771-Step will also require different trowels depending on whether the installer is using the system as an adhesive alone or as an all-in-one product.”
One of the company’s latest three-in-one products is Titebond 821-Step Adhesive, Moisture and Sound Control system. “Titebond 821-Step offers everything installers want in a robust urethane wood flooring adhesive but with the convenience of a three-in-one product,” Lamanno explained. “It also offers a longer open time than our advanced polymer Titebond 771-Step, allowing installers extra time to position flooring in place.”
Titebond also recently introduced pouch packaging for its Titebond 771-Step and Titebond 811 Advantage adhesives. According to Lamanno, “The 0.75-gallon foil pouch makes for a smart alternative to the pail. Pouches are sold in two- and four-pouch boxes, which are easy to carry to the jobsite. Once there, the installer removes the pouches from the boxes and positions them across the installation area based upon expected yield per package. The installer simply moves on to the next pouch in reach as installation progresses.
“The pouch is easy to open and less messy to apply. The installer just snips the tail on the pouch, squeezes out the adhesive, then spreads and trowels it. Adhesive placement is precise, resulting in quicker, more uniform spreading. The pouch size also reduces adhesive waste and cost. The weather-resistant pouch packaging keeps the adhesive fresh, resulting in longer shelf life and easier spreading and troweling. In addition, the pouch size results in less unused product that would otherwise skin or go to waste.”
Eric Kurtz, Bostik’s market manager for hardwood, resilient and surface preparation systems, said when selecting an adhesive to “always consider the application, the materials being bonded, the limitations of the adhesive and the expectations of the owner. Sell the features. Most owners would gladly pay more once they understand the value being offered.”
For example, several of Bostik’s products contain AXIOS Tri-Linking technology, including GreenForce and Ultra-Set SingleStep2 adhesives. According to Kurtz, AXIOS technology “uses unique polymers that offer exceptional workability, extreme moisture vapor protection and easy cleanup, even after cure.”
He added, “Ultra-Set SingleStep2 also features Bostik’s patent-pending Thickness Control Spacer Technology that offers exceptional sound abatement (equivalent to 1/4 in. cork or rubber underlayments) and ensures the proper membrane thickness is maintained. Installers can walk on the work immediately, without concern that the adhesive will squeeze out from underneath the board and compromise the moisture vapor protection or sound-blocking capabilities.”
John Brown, DriTac southern area technical sales manager, said that his company offers premium adhesive options in three technology platforms: water-based, modified-silane (MS) polymer and moisture-cured urethane.
He stated, “Whether roll-on or trowel-applied, following the manufacturer’s application requirements is essential to a successful installation. Several manufacturers require that installers replace their trowel for each new pail of sound and moisture control system adhesives used. DriTac allows installers to utilize DriTac 7800 Supreme Green and all of our other sound and moisture control system adhesives with the required trowel for a maximum of 800 sq. ft.”
The company’s latest products include DriTac 7800 Supreme Green hybrid polymer adhesive and DriTac 4141 Golden Bullet urethane adhesive. Both multifunctional adhesives “provide unlimited subfloor moisture control with no testing required and a lifetime warranty,” Brown noted.
He added, “Utilization of either DriTac 7800 Supreme Green or DriTac 4141 Golden Bullet allows end-users to turn what has traditionally been a two-to-three-day process into a time-efficient, one-day installation that saves the consumer money.”
Neuberger said preparing the substrate to receive the adhesive and flooring is crucial to a successful installation. “Adhesives are similar to the finish in that a clean, sound and secure surface is needed prior to the application of adhesive. If these conditions are not met, the chance of failure increases tenfold.”
He added, “Make sure the concrete has been properly prepped prior to application—this may include using a primer to strengthen the substrate or push down potential contaminants.”
His company’s latest adhesive is called Pallmann P5. “It contains silane technology and the ability to glue down engineered flooring with no length/width restrictions, and solid flooring up to 8 in. wide with no length restrictions.”
Resilient flooring adhesives
Johnson noted that silane-based adhesives are not only being used under hardwood but are migrating over to resilient floors as well.
“The formulation advantage of silane-based adhesives is that they are versatile and can be designed to do just about anything with just a little tweaking of raw materials. They can be formulated with short or long open times, high or low viscosities, and bond very well to a wide variety of materials,” he said. “The downside, if any, is that they are typically more expensive—but with increased production and range of use, the cost does appear to be decreasing.”
Johnson said it is crucial that installers take the time to become familiar with an adhesive’s application requirements before diving in.
“All flooring adhesives have unique and special installation requirements and the worst thing an installer can assume is that they are all the same,” he stressed. “Key success factors for any flooring adhesive includes reading the technical data sheet provided by the manufacturer, using the appropriate adhesive for the flooring to be installed, placing the adhesive with the correct notch trowel—which needs to be in good condition—and installing flooring within the adhesive’s stated working time window.”
One of MAPEI’s latest adhesives for resilient flooring installations is Ultrabond ECO 373, which Johnson calls “a super-aggressive, pressure-sensitive adhesive that is designed for the installation of a wide variety of resilient flooring types including concrete (at least 28 days old), cement terrazzo, exterior-grade plywood, cement-based self-leveling underlayments and patching compounds, gypsum underlayments, radiant-heat systems and MAPEI epoxy moisture barriers.”
Kurtz shared details on several resilient flooring installation products from Bostik. “XL Brands’ HydraStix 95 Resilient can be used with most resilient floorcoverings with slab RH up to 95%, and pH up to 11.0. It has 0 VOCs, great coverage, and excellent bond and shear strength.
“HydraStix 95 Aerosol offers these same performance attributes, but comes in a spray can so the installer can avoid troweling on their hands and knees.
“Additionally, DS 99 is an effective vapor barrier that can be used on slabs up to 99% RH and 12.0 pH. It is a one part, 0 VOC formulation that is easy to spread and is self-healing so that it cures to a uniform barrier in about 4 hours in normal temperature & relative humidity.”
Battiste said one trend she’s seeing in resilient adhesives is newer ways to apply them. “Moisture-tolerant adhesives that can be applied with a roller can cut installation times by 25% while saving the contractor wear and tear by not having to be on the ground during adhesive application.”
Her company’s TEC RollFast adhesive goes on with a nap roller. She said that the product is “formulated using installer-friendly technology for easy handling, application and clean-up to reduce fatigue. With moisture resistance up to 95% RH, RollFast may eliminate the need for moisture mitigation on newly poured slabs. RollFast allows the installation of LVT, LVP and vinyl sheet goods in 10 to 15 minutes.”
Along with roll-on and spray adhesives, Roberts listed other technological advancements in the category: “immediate loading capabilities, adhesive tape [formats], moisture resistance and environmentally friendliness.”
She added, “It’s important for installers to know how to apply an adhesive using the proper tools, the moisture limits and the right substrate preparation. Installers should also always be aware of local codes for proper waste disposal.”
Her company’s newest adhesive is Schönox HPS 1100, a clear, thin-spread, acrylic adhesive suitable for bonding VCT on porous and non-porous substrates in interior areas. “It is solvent-free while offering a quick dry time and extended working time, and is ready for immediate foot traffic and heavy traffic after two hours. Schönox HPS 1100 is packaged in a 4 gal. plastic container with an open time up to 16 hours,” Roberts said.