Acclimation Also Important in Summer

By Christopher Capobianco

For floor coverers, the way we work in very cold or very warm weather is a detail that is often forgotten and, if not handled correctly, can lead to problems. We hear talk about “acclimation” and most often think of the cold weather months. However, I’ve seen as many, if not more, problems with flooring that is not properly acclimated in the summer.

Delivering floor covering materials to the job ahead of time to allow material to acclimate or “acclimatize” to job site conditions is a good idea no matter what time of year it is and regardless of what kind of flooring material is being installed. That said, instructions regarding acclimation are often ignored, and industry standards have been published to call more attention to this important issue. For example, ASTM F 710, Standard Practice for Preparing Concrete Floors to Receive Resilient Flooring states that “General recommendations are for the installation area and materials listed above to be maintained at a minimum of 65 F (18.3 C) and a maximum of 85 F (29.4 C) for 48 hours before, during and for 48 hours after completion of the installation.”

For work done in occupied space, it’s a matter of getting the material into the space ahead of time so it can acclimate to the site conditions. This is most important when the weather is very cold or very warm. However, on new construction, the heating/ ventilation/air conditioning (HVAC) systems are often not activated at the time finishes are being installed, so the conditions on site can be an issue as well. I still see many cases where material is being delivered and installed the same day, with no thought for the fact that it’s been in a hot warehouse and/or a hot vehicle.

Acclimation is an accepted practice for wood, laminate, cork, bamboo and other natural materials at all times of year. It is a common understanding that wood expands and contracts with changes in temperature and humidity so most people “get it” as far as acclimating natural products by delivering them to the job two or three days ahead of time and making sure the climate control system in the building is operational. However, the necessity of acclimating other floor covering products is not as widely understood, and these products are often installed in less-than-ideal conditions.

Problems with resilient flooring or vinyl back carpet tile related to job site conditions are seen most frequently in the form of gaps in tile, which is usually blamed on shrinkage. It’s not that the material shrinks after installation, but that it stretches during handling if it is warm or may “grow” slightly. Rectangular vinyl products such as wall base, edgings or plank are easy to stretch during handling by carrying cartons over your shoulder and allowing the box to bend, pulling warm material out of the end of the carton, or stretching the material end to end as you are setting it into the adhesive. These actions can stretch the material ever so slightly, but you’ll have tight seams until the temperature cools to normal, in-use, conditions, the material relaxes back to its original size and gaps become visible. If you ever notice an installation of vinyl flooring where the floor tile, the reducers or the wall base are gapped, it’s a good bet the job was done in the summertime and the material was not acclimated.

While we are on the subject of vinyl, let’s look at rigid-core products that install as a “click” floating floor with attached cushion — sometimes called WPC, SPC or HPC. For these products, when it comes to acclimation, read the fineprint. Some of these products are marketed as “acclimation is not necessary,” others require it, and in other cases, it’s confusing. One manufacturer says acclimation isn’t necessary but “the floor covering should be installed in a climate-controlled environment with an ambient temperature range temperature between 55-85 F (13-29 C) or average temperature of 70 degrees (21.1). So, the product doesn’t need to be acclimated but the space where it’s to be installed has to be. Make sure you are clear on this, and when in doubt, it’s not a bad idea to deliver the material a day or two ahead of time.

When it comes to stretch-in carpet over pad, most installers would probably prefer installing carpet when it’s on the warm side as opposed to in the winter months. The shop where I grew up working kept a lot of the carpet in storage in an unheated garage, so in the winter it was tough to work with if it was installed the same day. If you’ve ever handled cold carpet, you know it can be stiff as a board. But, if we got the material onto the job a day or two ahead of time, it was a lot easier to install.

On the other hand, warm carpet can be a problem if the carpet is overstretched, which is not hard to do when it’s warm. Overstretched carpet can pull away from walls or seams if relaxes too much as it cools. The Carpet and Rug Institute (CRI) standards for carpet installation (CR104 for Commercial and CR105 for residential) mention acclimation specifically, “The carpet is to be installed when the indoor temperature is between 65-95 F (18- 35 C) with a maximum relative humidity of 65 percent.” Proper stretching of carpet is also specified, as follows; “Due to the difference in carpet-backing types, it is required that manufacturer recommendations for carpet stretch be followed. In the absence of specific recommendations, tufted carpet with synthetic backing should be stretched a minimum of 1 percent in length and in width. Patterned carpet may require additional stretch to obtain pattern match.” If you haven’t seen these documents, it’s a good idea to get a copy and stay up to date on the latest industry standards.

Example of vinyl plank floor with visible end joints. Material was installed in summer without acclimation. The joints were tight after installation but when the material “relaxed” the planks returned to their original length and the gaps became visible.

In addition to the fact that floor coverings can be affected by warm temperatures, adhesive may set up very quickly in warm conditions, so open time and working time can be affected. There can also be issues with underlayments used for resilient floors, which may expand slightly when they go from cold to warm. ASTM F1482 Installation and Preparation of Panel Type Underlayments to Receive Resilient Flooring* has an entire section on Material Storage and Conditioning that uses a lot of this same language.

Finally, moisture is another factor when it comes to acclimation of a job site. In preparing to install wood floors, a wood subfloor may be too dry or too moist if the space is not climate-controlled. Too wide a difference in moisture level between the subfloor and the wood flooring can cause a variety of problems from gapping to cupping to buckling after the floor is installed. In the case of concrete floors, moisture test results can be affected by the ambient conditions.

For example, the ASTM F 1869 Calcium Chloride test method calls out for very specific temperature and humidity; “The test site should be at the same temperature and humidity expected during normal use. If this is not possible, then the test conditions should be 75 ±10 F (18.3 to 29.4 C ) and 50 ±10 percent relative humidity. Maintain these conditions 48 hours prior to, and during testing.” If the test can’t be done under these conditions, don’t bother doing the test.

As you can see, site conditions and acclimation affect many aspects of floor covering installation. All flooring materials have acclimation recommendations as part of the installation instructions, but these recommendations are often ignored. Following these guidelines can eliminate a number of problems, reducing callbacks and eliminating complaints.

Christopher Capobianco has been in the floor covering industry since the 1970s in various roles including retail and commercial sales, technical support, consulting, journalism, education and volunteer work. He currently is part of the sales team for Spartan Surfaces in New York City. You can reach him via [email protected]

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