Remove any flooring that will not provide a solid base for the laminate or hardwood you intend to install over your underlay, such as carpet, loose tile and other flooring that is not level and smooth. Use a floor scraper if needed to remove stubborn materials.
Sweep and mop the entire installation area and allow it to dry thoroughly. Ask to be sure that new concrete has been allowed to cure for at least 60 days, and use a calcium moisture detector if you are still not certain the floor is ready.
Set the detector on the floor and gauge the results by the included chart to determine if the moisture content is low enough.
Roll out the first row of underlay perpendicular to the longest wall in the space with one edge against the wall. Trim the roll at the wall so that it fits snugly, using a utility knife to cut the underlay.
Lay the next row along the outside edge of the first row, butted up snugly, but not overlapping. Roll the material out to the wall and trim it against the wall as you did with the first.
Tape the two rows together with a strip of duct tape to fasten them together. Trim the duct tape off at the end of the row.
Continue adding Quiet Step 2-in-1 underlay in rows across the floor to the opposite wall. Use the full width row as far as possible. Tape the seam between each row.
Roll out a last row and cut it to length. Roll it back up snugly.
Measure to the wall and mark the roll to that same width. Use a miter saw to cut through the roll smoothly so that the entire row is cut to width.
Roll the last row into place. Tape the last row in place.