A good flooring underlayment will help to deaden the sound of the room and will also serve as a water barrier. This added protection will help guard against the floor warping in the future. Installing underlayment for your floor is a very easy process that can be done as a precursor to your final flooring.
Step 1 - Measure Room
Before you head off to the hardware store, measure your room to find the square footage. You will need this when you purchase the underlayment. Typical underlayment comes in 100 sq. ft. roles, but this can vary according to the type of underlayment you choose. Some manufacturers have their own underlayment that they recommend for their laminate flooring. However, there are several different kinds to choose from with different thicknesses. Ask the hardware store clerk which type of underlayment you will need.
Step 2 - Prepare Area
Take some extra time to clean the floor of the room you are going to lay the underlayment in. Completely clean off the subfloor of any debris, dirt, rocks, or anything else that can move around and cause tears in the underlayment. If there are any scratches, or holes in the subfloor, now is a good time to fill them with leveling compound or putty. Sweep the floor and give it a good scrubbing. Let the floor dry completely.
Step 3 - Lay Down First Row
Start in the corner of the room where you are going to start laying down your laminate flooring. Unroll the first line of the underlayment. Use a utility knife to cut it near the opposite wall. Begin laying down your first row of laminate flooring. If your underlayment is thin it will tend to shift and slide while you are laying down the actual flooring. This will cause problems with bumps and areas of the subfloor that are left uncovered. Once the first few rows of flooring have been installed, then you can continue with the underlayment.
Step 4 - Cover Subfloor
As each new row of flooring is put down, you can continue rolling out the underlayment for the next row. Connect each new row of flooring underlayment to the next by covering the seams with carpet tape. If you do not have enough in one roll to finish a complete row, then simply roll out another where that one leaves off and connect with the carpet tape.
Once the entire floor is completed you will notice that the floor has a certain spring to it instead of being hard and rigid. If you notice that the flooring is bulging in some spots, or starting to pull apart, then it might be the flooring underlayment. It might have shifted as you were laying that row and didn't notice it. You will have to pick up the flooring in order to fix it.