How to Choose the Right Flooring Adhesive
By Brack Dukes
Adhesive is a critical component of installing a floor and helps ensure it withstands long-term use and continues to perform well. There are several factors to consider when selecting the best adhesive for the job, including application, installation and moisture limitations.
Types of Adhesive
Before even starting a project, it’s important to have knowledge of available adhesive products to make an informed choice.
Acrylics are the standard, most used type. However, they create a softer result that can displace if used in the wrong conditions.
Tapes and sprays can be various bases but are generally acrylic, offering a thin alternative. There are also urethane and epoxy options, which are usually two-part products that dry to a harder finish after curing than acrylics.
Use Considerations
To choose the best product for optimum performance, start by evaluating how the area will be used along with the type of flooring to be installed. Acrylics are often applied in high-traffic areas. This traffic may come from people walking or rolling loads, such as dollies used to move relatively light to heavy equipment.
Note the difference in heavy point loads versus heavy rolling loads. A heavy point load means the load will be stationary for an extended period of time whereas a heavy rolling load travels across the floor.
In environments with rolling heavier point loads, urethane or epoxy is a better option. Areas with stationary hospital beds, such as patient rooms, are a good example of a space where using a two-part system that sets especially hard is preferred. Otherwise, indentations may occur in the floor.
Keep in mind it’s not always a one-product solution. Different spaces in the same building may have different requirements. Acrylic is fine for hallways where people walk and hospital beds are in motion or only stopped for short periods, but hard-set, two-part adhesives may be better suited for other uses in the building.
The Moisture Factor
Moisture is a consideration in almost every aspect of selecting flooring materials. Luxury vinyl tile (LVT) and sheet vinyl are waterproof. Carpet depends on the backing, with higher moisture alternatives being porous and allowing moisture to pass through. Rubber is porous and will absorb moisture without allowing it to pass through, resulting in expansion and contraction that can cause gaps in the installation.
The adhesive is dictated in part by the type of flooring material and its moisture resistance. A tape system allows the entire back of the flooring to be covered, essentially placing an adhesive layer between the rubber and moisture. Some type of moisture barrier is necessary if the concrete slab has a high moisture content.
The age of the slab impacts moisture. Building codes on most new construction require a moisture vapour retarder, which is basically a thin layer of plastic installed between the concrete and ground. A high moisture reading in a new slab could mean the concrete is still curing. The moisture will evaporate out in a couple months.
With a slab that’s five to 10 years old, a high moisture reading indicates there’s a tear in the vapour retarder or one was never installed. These cases require mitigation but there are viable adhesive options. As examples, LVT needs the right adhesive whereas carpet needs a combination of an adhesive and a backing system. The correct product combination is necessary for the installation to be covered by warranty.
The Right Product for the Job
The type of flooring is an obvious factor in selecting an adhesive. The products must be compatible. Some adhesives just don’t work well with rubber and some aren’t made for vinyl products. Sometimes it’s not that the adhesive won’t work; it just could be overkill for the flooring being installed.
The different types of adhesives and installation methods can get complicated, but they don’t have to be overly complex. There are wet sets and pressure sensitive adhesives. Wet sets are usually applied with a trowel and are installed into, just as the name suggests, wet. When these adhesives set, they don’t release. They cure to a hard-set, meaning the flooring cannot be repositioned after it sets. Drying can take as little as 24 hours, while a full cure can take up to 30 days.
Pressure sensitive adhesives take just 30 minutes to become tacky but you can reposition the flooring. That makes installing carpet tile with a lot of seams easier. Unlike a wet set, there’s no tendency for the adhesive to come up through the seams, which requires more cleanup.
Always follow the manufacturer’s recommendations for the right type of adhesive to use with a product. Utilizing an adhesive that isn’t recommended can negate the bond warranty with the flooring manufacturer, which would make addressing any failure situation complicated. Also, follow the correct installation guidelines for optimum performance.
Brack Dukes is senior product manager of carpet, rugs and rubber at Mannington Commercial, a leading manufacturer of modular and broadloom carpet, luxury vinyl tile, resilient sheet and rubber flooring.