The shinier or smoother side goes up when installing carpet pad. This allows the carpet to slide across the pad while it is laid out and installed.
The carpet pad is unrolled to the maximum length but only just to the inside edge of the tackless strip. The pad is then stapled around the perimeter and along the seams if the carpet is being installed over a wood subfloor; the staples should be about 8 inches apart. If the carpet is being installed over a concrete subfloor, glue is used to attach the carpet pad to the subfloor. The seams of the carpet pad are taped with duct tape, carpet tape or another industrial-strength tape in order to keep the pad from shifting around after the carpet is installed.