Underlayments pads are especially important for engineered floors or laminate floors which are installed via the floating method over wood or concrete subfloors. When you float an engineered or laminate floor, none of the boards are actually attached to the subfloor. An underlayment is necessary for multiple reasons, floating floors will expand and contract, moving ever so slightly as a whole unit. The smooth surface of the underlayment allows the flooring on top of it to move slightly during seasonal relative humidty changes. Underlayments are also are used under floating floors to act as a cushion, allowing for a bit of a softer feel when walked upon.
Underlayments pads these days are made with an attached plastic moisture retarder. 4-6 mil Plastic moisture retarders are basically non-negotiable when it comes to installing over concrete subfloors, we always recommend the use of a moisture retarder over concrete subfloors.
Underlayment pads also helps to even out subfloors which may have minor imperfections, which is important for a smooth floating installation process.
Lastly, some underlayments pads have exceptional sound absorption properties and can be used as a sort of sound insulator, preventing sound transfer.
There are a multitude of underlayments available for floating installations. They range from simple foam pads to foam pads with a plastic moisture retarders attached to dense felt-like underlayments with remarkable sound absorption properties. Foam pads are typically thinner and their sole purpose is to add a little cushion. Foam pads with moisture barriers attached are also on the thinner side but also offer that moisture protection. The denser underlayment pads are typically a bit thicker and offer more support and insulation because of there dense nature. Please note… that “Regular Carpet padding” is too thick and soft to use as an underlayment pad for any wood or laminate flooring and could cause the joints of the flooring to break when walked on.
It’s important, prior to installation, to read the specific flooring installation instructions. If they require use of underlayment in order for their warranty to be effective, it’s always a good idea to acquiesce.
Installation of underlayment for a floating floor is very simple. Underlayments come in rolls. After subfloor prep, simply roll out the underlayment. Underlayments that Homecraft Remodel Supply stocks all have self-stick overlap flaps for connecting multiple sections of underlayment together.