LVP/LVT has become the biggest category in resilient flooring over the last few years. With that comes product/installation issues that I deal with every day. Gapping, peaking, buckling in sunlight, and buckling due to lack of expansion. Below are my best installation practices.
Glue Down LVT/LVP Best Practices
- Acclimation — LVT and LVP need to be acclimated. If it contains vinyl in it, it will grow when warm and contract when cool. Keeping your LVT/LVP stored in your hot van or truck for hours and then installing it in a climatized house will lead to gapping. The opposite happens when keeping the LVT/LVP stored in a cold truck in the winter for hours and then installing it in a climatized house will lead to the product peaking. Do not expose to sudden changes in temperature.
- Unfortunately, the new construction markets have yet figured out having the building/homes climatized can help solve a host of issues. These products have always had temperature requirements and it is not new. These markets have just chosen to ignore them and hold everyone else accountable.
- Working Time — Honor the working time of the adhesive. If the adhesive has a 3-hour working, this means that when the adhesive goes dry to the touch, I have 3 hours to install my LVT/LVP. Know what the working time of your adhesive and adjust your spreading of the adhesive to the working time so you know your maximizing the strength of the adhesive. LVT/LVP Adhesives are not like VCT Adhesives that have up to 24 hours working time. VCT is 85% Limestone and has very little movement, unlike LVT/LVP.
- Trowel Notching — The working time and the spread rate of the adhesive are based and tested off the correct trowel notching. You change the trowel notching, you now just changed the working time and also the bond the adhesive has with the LVT/LVP.
- Remember to change out your trowel blade. Concrete wears them down and again it will change the properties of the adhesive.
- There are more and more roll-on adhesives being introduced. If the adhesive requires a roll on with a specific nap roller, follow the recommendations. Again, I change the roller nap specs, I change the performance of the adhesive. Same as above, change out your roller from day to day.
- Use a 100-lb. Roller — For glue down LVT/LVP, rolling the floor with a 100-lb. roller is the best thing you can do. Rolling the floor helps seat the LVT/LVP into the adhesive (if placed within the correct working time). Rolling of the LVT/LVP is especially essential in areas with a lot of sunlight. LVT/LVP in these areas are seeing a lot of heat during the day and cooling at night. So, it is growing during the day and shrinking when the sun goes down. If the LVT/LVP is not seated firmly into the adhesive, it will not be able to hold down and control the growing/shrinking that these products will see on a daily basis.
- If the adhesive requires a 100-lb. roller this is what it requires. Not a broom, a rolling pin, or even a 2” x 4” with carpet on it. Use a 100-lb. roller.
- Note; if the LVT/LVP is curled or domed coming out of the carton, do not install it. The adhesive does not have the strength to hold down this manufacturing stress and defect and it will fail. This is a claim.
Floating LVT/LVP and Rigid Core Best Practices
- Acclimation — Same as above. Do not expose to sudden changes in temperature.
- Subfloor Flatness — The specs for a subfloor for resilient flooring is 3/16” in 10 feet or 1/8” in 6 feet, the same as a glue down floor. Some manufacturers have gone as far as 1/4” in 10 feet. The more humps I have in a floor, the more deflection and squeaking issues I have. Too much deflection and I can break the locking system.
- Expansion Zone — Generally, the expansion zone for floating products is 1/8” or a 1/4” away from all vertical surfaces such as walls, cabinets, pipes, etc. This means every plank needs to have expansion. One net fit piece can affect a large area of the installation.
- Sunlight — The use of drapes or blinds is recommended during peak sunlight exposure. If expansion, due to sunlight exposure, occurs in a specific area, you may want to think about gluing the product down (following the best practices above).
- Room size Limit — A lot of these products give no room size limitations. But please remember the days of Laminate flooring when it would get hung up in doorways and buckle. Same thing applies with LVT/LVP. Remember, it grows and shrinks, and doorways are trouble areas.
Other LVT/LVP and Rigid Core Notes
- Waterproof is the most over used word in the flooring vocabulary. LVT/LVP and Rigid Core products all have subfloor moisture requirements. The product may be waterproof (and it always has been) but the installation system is not.
- Don’t believe all the marketing hype of being able to go over a bad substrate with a lot of these products. If you go over a bad subfloor and the installation fails, it’s a turn down claim. Bottom line, you’re only as good as what you go over.
- Not all locking systems are the same and do not work the same. Know how the product goes together. I wrote an article on locking systems a few years ago. If you would like a copy, please let me know.
Why Is My Concrete Still Wet?
This is becoming more of the normal in the construction business. Construction schedules are rushed, HVAC Systems are not in place to dry out the air, which in turn allows the concrete to dry out. The rush to have very fast construction schedules has created more and more problems with concrete subfloors being allowed to dry sufficiently. But, there are other factors as I got to see on a newly poured concrete slab which happens every day in new construction.
The photo below shows a typical slab with a vapor retarder and wire mesh on it ready for the concrete pouring.
- Rain water on top of the Vapor Retarder — It rained the evening before and the morning of the concrete pour. This excess water will take the slab longer to dry out, especially if the enclosed building does not have the Heating and Cooling System up and running.
- Holes in the Vapor Retarder — At this job site, they were poking holes in the Vapor Retarder with metal stakes and also cutting the vapor retarder for letting the excess rain water off. This vapor barrier is now compromised and future for potential ground moisture now has a path to the concrete slab.
- Excess Water in the Concrete Mix — On hot days, extra water may be added to the concrete mix to help the concrete flow and be placed easier. Adding extra water to the mix adds extra time to the drying of a concrete slab. A good concrete mix should have a Water/cement ratio: 0.40 to 0.45.
- Power Troweling of the Concrete — If the concrete is power troweled and the surface of the concrete is like glass, the surface of the concrete will be sealed off and not allow the natural hydration process (drying out) of the concrete to happen. Basically, the sealed concrete surface has removed the pathway for the excess mix water to escape.
These are just a few factors in the construction process that can affect the moisture issues of a concrete slab, which in effect can lead to flooring problems down the road. There are other factors once the structure is up that prolongs the drying out of the concrete slab that I will touch on in a future article.