Vinyl plank flooring has been all the rage in showrooms over the past few years, and a favorite for home flippers who want to quickly spruce up an investment property for a quick sale. Unfortunately, what many consumers and contractors assumed to be a waterproof, trouble free, wood-look plank flooring product, has proven to be a product with many problems, and a product that, if not properly installed, is prone to failure, or worse can result in the growth and propagation of mold.
What is Vinyl Plank Flooring?
Luxury vinyl plank flooring, or LVP, has actually been around for a while, but the product didn’t really take off until vinyl composite products such as WPC (wood poly composite) and SPC (stone poly composite) became widely available in showrooms. Marketed as waterproof, both consumers and contractors began slapping this product down with little thought as to proper installation techniques and substrate preparation.
Luxury vinyl plank is a type of resilient flooring, and two popular variations of luxury vinyl plank are WPC (wood poly, or plastic composite) and SPC (stone poly, or plastic composite). Both of these products are an improvement of standard luxury vinyl planks because they allow for a thicker plank, a stronger locking system, and the ability to install the products floating. There are versions of standard luxury vinyl plank that come with locking systems allowing for a floating installation, however, it is the experience of this flooring inspector that standard luxury vinyl planks are not thick enough to accommodate a locking system able to provide sufficient locking strength, resulting in a tendency for standard LVP products to separate and form gaps.
The addition of wood or stone (usually limestone) flour, allows for a thicker plank and a stronger locking system. There are other benefits such as sound dampening, a minimizing of subfloor defects transferring upward through the plank visually, and a generally more sturdy feel when walked on.
There are definitely benefits to choosing a WPC or SPC floor, as long as the products are installed correctly in an appropriate application, and very importantly, over a substrate that is flat and properly prepared. That means moisture testing, and if necessary, the installation of a moisture vapor retarder.
The following are some common mistakes that homeowners and contractors make when installing luxury vinyl plank flooring that can result in cupping, buckling, or flooring failure.
Installing Over an Abandoned Hardwood Floor Installed Over On-Grade Concrete
This would include plywood, either underlayment attached to on-grade concrete, or as a filler. Example: filling in a carpeted area that meets up with ceramic tile. This is sometimes done so that the new floating floor can be installed over a flat surface.
Never install a floating floor, especially LVP, WPC or SPC, over abandoned wood flooring, or any other moisture sensitive material attached to on-grade concrete!
Remember how this vinyl plank flooring is marketed as waterproof? it may not be entirely waterproof, but it is very water resistant and will trap moisture vapor in the concrete slab, and when this moisture vapor is trapped, the abandoned hardwood flooring underneath new vinyl plank floor will become saturated and eventually decay, and possibly become moldy.
If moisture buildup is sufficient, the wood flooring will expand and then buckle underneath the vinyl plank floor. This problem has caused many homeowners and contractors to scratch their heads thinking, “what happened, the floor’s waterproof.” Exactly, but wood flooring is not.
Over on-grade concrete, remove wood flooring before installing vinyl plank flooring. No exceptions.
No Moisture Vapor Retarder Used
Some vinyl plank flooring manufacturers are starting to catch on and change their installation instructions. Most, if not all, will require moisture testing for on-grade concrete slab applications. Some are now recommending the installation of a 6mil poly moisture barrier over on-grade concrete.
The installation of a 6mil poly moisture barrier should have always been a requirement for the installation of floating luxury vinyl plank flooring over on-grade concrete. It does not matter if the planks have an attached pad. If an on-grade concrete slab is not covered with a sufficient moisture vapor retarder, the new vinyl plank floor will be prone to failure.
Here’s where there seems to be a disconnect with homeowners and contractors regarding this so-called waterproof product:
“If it’s waterproof, or even water resistant, why is it necessary to install a moisture vapor retarder over on-grade concrete?”
The reason is this:
Although submersion in water will not damage a luxury vinyl plank, it will change its dimensions. That is why when installing resilient flooring over on grade concrete, the same standards used to install hardwood flooring should be used to install resilient flooring. In fact, if you Google the ASTM standard for preparing a concrete slab to receive hardwood flooring, “ASTM F 710 Standard Practice for Preparing Concrete to Receive Resilient Flooring” will come up as the top search (last I checked). That is because there is no ASTM standard for preparing concrete to receive hardwood flooring. The standard for resilient flooring is used because it was already written and sufficient for hardwood flooring. Therefore, it makes no sense to conclude that resilient flooring requires no moisture protection.
Standardized moisture testing must be performed on concrete prior to the installation of vinyl plank flooring. This is no different than if hardwood flooring were to be installed.
The problems is, moisture tested is routinely omitted. I have yet to have provided for me documentation of moisture testing performed by a contractor who had installed a vinyl plank floor that failed. Admittedly, this has been my experience and is therefore anecdotal. But it seems that the story is the same every time: A vinyl plank floor fails. It cups, or buckles. There’s moisture underneath. A plank is pulled up and it smells. Doesn’t make any sense because this floor is waterproof and there must be a leak, but no leak can be found. It’s simple, it’s groundwater, it’s trapped underneath the waterproof flooring and has nowhere to go. So the attached cork underlayment starts to deteriorate. The underside of the vinyl plank begins to swell. The pH starts to rise due to salt migrating upward from the concrete slab. The high alkalinity starts to deteriorate the vinyl planks, etc.
There is no repair option. The floor needs to be torn out and replaced, hopefully by a contractor who understands the effects of substrate moisture on a flooring system.
Improper Installation
Because luxury vinyl plank flooring is a floating flooring system, the same type of installation shortcomings that would cause damage to a laminate floor will affect a vinyl plank floor. In my experience, problems seem even more common because of this perception of vinyl plank flooring being waterproof.
Failure to incorporate an expansion space at all vertical obstructions can result in buckling. This means at the floor’s perimeter, at fireplace hearths, patio doors, and transitions to other types of flooring. No one likes transition moldings, but with a floating floor they’re necessary.
If your vinyl plank floor is butted up nice and tight to your fireplace hearth because you told your contractor that you don’t like the looks of transition moldings, eventually the floor is going to expand, and there’s a good chance you’re going to get areas that move when walked on, are cupped, or buckled.
Should I Have Luxury Vinyl Plank Flooring Installed?
Luxury vinyl plank, LVP, WPC, and SPC can be installed trouble free if done properly. It is the opinion of this flooring inspector that of the three, standard luxury vinyl plank (LVP), especially the glued down variety is problematic and not recommended.
WPC and SPC can be great products. Just make sure the substrate is flat. That means within 3/16″ for every 6′. Test the concrete slab for moisture using standardized tests, and cover the concrete slab with 6mil poly sheeting, overlapped six inches and taped, and extending up the wall at least two inches to be covered by the base moldings. Make sure there is a 1/4″ gap at all vertical obstructions, and do not install the baseboards too tight. The floating floor has to be able to move freely underneath the baseboards.
Never install cabinets on top of a floating floor, and heavy objects such as fish tanks could be a problem. If installing in a sunny area, or in front of a large patio door that gets a lot of heat, be extra careful to maintain that expansion space.
No flooring product is completely without problems, even when all measures are taken to prevent them. But taking care to prepare the substrate, and installing the product properly will minimize problems.
Also, stick to reputable brands that have a track record of quality. A lot of manufacturers, many of them unknown in the U.S. marketplace, have jumped on the vinyl plank bandwagon. Preparation and good installation can minimize problems, but they can’t prevent problems if a product is poorly manufactured with low quality materials.
Dave Fitzpatrick is a licensed C15 and C54 flooring inspector who provides opinions for the property liability industry.