Do You Have to Glue Down Underlayment for Plank Floors?

Installing Underlayment

• Standard underlayment foam is thin foam about 1/8 inch thick. This type of underlayment is generally used where there are no moisture or sound barrier concerns. Moisture barrier underlayment is standard foam attached to 6 mil polyurethane film, which forms a moisture barrier. Denser underlayment, also called modified underlayment, is used as a sound barrier between floors. These types of underlayment are not glued to the subfloor.

Laying Underlayment

• The underlayment pieces are laid seam to seam so the seams are not overlapping. After laying the underlayment, tape is used to tape the pieces of underlayment together. The only time you overlap the underlayment at the seams is if you are using additional plastic sheeting to protect the laminate from moisture.

Cork Underlayment

• If you are using cork underlayment, you must glue the cork to the subfloor, according to Floor One. Cork has strong sound barrier qualities. This type of laminate underlayment is chosen for condos because it can deaden the noise between floors. Underlayment of this type is generally 1/4 inch thick. After the glue is applied, a weighted roller is rolled across the cork to remove air pockets and give the floor a better seal.

Glued Laminate

• When you use glued laminate planks, you do not glue down the underlayment; instead you glue the laminate. Glued laminate is either pre-glued or glued laminate. Pre-glued laminate has adhesive already applied to the plank's tongue and groove area. As you use each plank, you wet the adhesive to activate the glue. The glued laminate needs to have glue applied to the tongue and groove before placing the planks together.