How to Fit Carpet Underlay

Clean the room you are going to carpet, making sure that all of the old floor coverings have been removed and that any furniture, electronics or other objects have been placed somewhere else.

Sweep the floor well, clearing it of dust and debris. Carpet underlay does help to make the floor seem smoother in areas with imperfections. However, it is always a good idea to clear away the obstructions that can be removed so that you start with as smooth a surface as possible.

Unroll a section of the carpet underlay that you have purchased. Allow the underlay to lay across the width of the room. If it does not reach from one side to the other, begin at the center of the room and roll the underlay toward the wall, allowing it to climb up several inches.

Use a very sharp blade to cut the underlay, leaving enough excess for it to climb part of the way up the skirting board of the walls. To cut properly for the thresholds, allow the underlay to flop through the doorway. This is not a final cut, just an approximation of the size that you will be aiming for so that you are breaking the underlay down to a more manageable size.

Make the final cut to fit the underlay using the edge of the carpet gripper as a guide. Cut the underlay at the spot where it touches the very edge of the gripper. This will ensure a tight fit for the underlay when attached to the carpet gripper. Do it the same way along the base of the threshold.

Once you have cut the first width of underlay, continue the process throughout the room as needed. Follow steps 1 to 5 until you have cut enough carpet underlay to cover the floor. Multiple widths of carpet underlay will need to be joined with seaming tape or duct tape.