Unlevel Subfloor Below Laminate Flooring
Most laminate floor manufacturers require a subfloor to be flat within 3/16″ over a 10 foot radius.
Since not all laminate manufacturers have the same standard you need to check the installation instructions for the manufacturer of the floor being installed.
Some manufacturers instructions will use the word level instead of flat while they are actually speaking of the floor being free of high or low spots.
A subfloor that does not meet the laminate manufacturers installation requirements must be leveled by sanding or filled with an approved floor patching material.
On a floating floor gaps can easily develop between planks when a subfloor is not level.
About Terry Weinheimer | Kevin Weinheimer
I have a friend that has recently installed a floating laminate floor throughout his house. The house is built on a slab and he used a vapor barrier for concrete installation. The laminate construction included a foam base integrated into each slat. Upon completion of the install, he experienced a localized area of oil canning, likely from the concrete floor being uneven. Is it possible to correct this localized “void” without pulling up the whole floor and leveling the concrete? I don’t know if there is something that could be injected between the laminate and the vapor barrier to fill the void? Any assistance would be appreciated. Thank you!
If you are using the term “oil canning to describe a wavy or uneven appearance or distortion in the installed floor there could be a number of causes. This may be a perceived appearance caused by lighting or an actual distortion caused by an uneven floor or even expansion of the floor. The first thing you need to do is determine if the problem is real or perceived and then you can look at a potential correction. As far as injecting a product if you could find such a product, this could cause additional problems if the flooring suddenly adhered to the underlayment or concrete as a floating floor must be able to move. If the problem is the slab the proper way to correct is to remove the laminate and either grind or float the concrete depending if high or low. Good luck and if others have a suggestion please be sure to offer it.
Terry