Thermal Expansion of Luxury Vinyl Tile and Plank Flooring

I am getting more and more complaints of LVT, LVP, EPC, and WPC products used in rooms with glass doors, skylights, or big window areas that are growing/expanding and then gapping, especially at the end joints. If these products contain vinyl, which they do, they have a great chance of failure in areas exposed to direct sunlight over long periods of time. This is not a new scenario. This has been happening for the last 10 years, but with the increasing popularity of these Luxury Vinyl products it has become very common today.

When floating LVT was first introduced (Konecto), this is when this trend started. The floating LVT was installed with expansion around vertical objects and the perimeter, but when the direct sunlight beat in on these products they would expand as vinyl does when it gets warm and grow and the expanding LVT flooring would eat up the expansion space and create pinch points and then it would start to tent up. The angling sunlight coming in through glass doors, skylights, or big window can hit temperatures of 120°F or more depending on the time of year, intensity of the sun and where the sun is positioned in the sky.

Expanding Vinyl From Heat and Sun

I have seen this scenario with floating, self-stick, and glue down Luxury Vinyl Flooring, EPC and WPC products. As the sunlight decreases, the flooring will start to contract and go back down to size. But this happening repeatedly day in and day out will cause floating floor locking systems to disen- gage, self-stick and glue down this has a shearing effect () on the adhesive and eventually the product loses its bond. I have seen Luxury Vinyl Planks with fiberglass inner layers grow up to 1⁄4” in the sunlight and then shrink back when the sunlight is blocked.

What is the flooring manufacturer’s liability in these applications? Absolutely none. If you read the manufacturer’s instructions, they usually have an area covering this scenario as listed below;

Installation in areas with sustained direct sunlight:
In cases where the flooring is in direct sunlight for much of the day (Sunrooms, etc.) and the interior temps will exceed 100 degrees, it is recommended that the planks be glued down in those spots/areas. The planks are still clicked together as per the floating installation instructions, but an approved premium Luxury Vinyl flooring adhesive should be used in areas as needed.

Should not be exposed to direct sunlight for prolonged periods. It can result in discoloration and excessive temperatures that may cause expansion. The use of drapes or blinds is recommended during peak sunlight exposure. If drapes or blinds are not going to be used and expansion occurs in this area, we recommend adhering this area with adhesive.

Direct sunlight may cause fading or the adhesive strip to separate. Protect from direct sunlight using window treatments or UV tinting on windows.

What is the remedy?

  • Floating Floors; I am not a fan of spot gluing a floating floor down as some manufacturers suggest.I feel this can create pinch points from the gluing down and cause failures other places. If I am go- ing to adhere a floating floor, I am going to do an overall area rather than spot gluing so I do not create pinch points. The downside of gluing a locking floor is that trying to angle up the flooring and tilt into place while it is in a pressure sensitive adhesive is not a lot of fun or easy to do.
  • Glue down floors; I always suggest wet setting the Luxury Vinyl Planking or Tile into a premium pressure sensitive adhesive. Maximize the bond. When an adhesive is allowed to dry to the touch, you are only bonding to the top of the adhesive ridge which is about 60% of the flooring surface area. When I wet set, I am creating an overall bond with the adhesive and covering about 90% of the flooring surface area.
  • Do not use low end adhesives. Use the premium adhesives in these areas, they have better ingredients and less filler.
  • Honor the working time of the adhesive. Many LVT Adhesives have a short working time. Work- ing time is how long I have to install the flooring after the adhesive has flashed off. There are some LVT Adhesives on the market with working times up to 1 hour. That is not very long. Even though the adhesive feels tacky, it has lost a lot of its bond strength. There are other adhesives out on the market with extended working times, Mapei 373 up to 12 hours working time, DriTac 5900 over 3 hours working time.
  • Roll the flooring with a 100-lb. roller. Help seat the flooring into the adhesive. Maximize the bond strength of the adhesive.
  • One adhesive that is promoting excellent adhesion is high sunlight areas is the Flexco MS 700. MS700 is a premium, one component Modified Silane Adhesive used for the permanent installation of vinyl & rubber flooring products, including recycled or crumb rubber flooring products. MS-700 is free of water, solvents, VOCs and hazardous chemicals. MS-700 is highly tenacious, waterproof and extremely resistant to high levels of moisture and alkalinity, whether topical or from the sub- strate. Adhesive is suitable for heavy traffic or rolling loads. I have used the MS-700 and checked its bond strength and it is a very nice adhesive with excellent bond strength.

    …The other option is to look into glass tinting or window treatments.

    When selling these vinyl products, understand the area where they will be installed. Is a floating Vinyl Plank the right product for an area exposed to a lot of natural sunlight? Confront the issues up front, rather than down the road when the product starts to fail and the customer is upset at the installation and the product.

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