Lay new carpet underlay correctly inside the gripper rods, join it neatly, and fix it to suit your floor.
LU-01Clear the room and check the subfloorMove out furniture and strip back any old carpet and underlay. Check the subfloor is dry, flat and sound — fill any gaps in floorboards and sweep concrete floors clean of grit. If the old underlay is in good condition and the new carpet's packaging allows reusing it, you can leave it down, but check it isn't crumbling, torn or damp first.
LU-02Check the gripper rodsGripper rods should already run around the edge of the room, pins facing the wall, with a small gap (about 10mm) between the rod and the skirting. Replace any that are loose, rusted or missing — nail timber gripper into a timber subfloor, or use masonry nails or gripper adhesive on concrete. The underlay will sit inside this gap, never on top of the rods.
10 metre · Carpet gripper rod 1 pack · Gripper nails or adhesive LU-03Measure and cut the underlay to fitRoll out the underlay and cut it to length with a utility knife, leaving strips slightly oversized so you can trim them later. If the underlay's instructions say to lay it at right angles to the carpet pile direction, mark that direction on the floor first with chalk or pencil so you don't lose track once pieces are down.
15 square metre · Carpet underlay LU-04Lay the underlay inside the gripper rodsPosition each strip inside the line of gripper rods, never overlapping them — the carpet needs to hook onto the pins, not onto a lump of underlay. Butt each join edge to edge, don't overlap them, and run a strip of underlay tape along every join to hold it flat. Keep checking the strips stay inside the rods as you work across the room.
1 roll · Underlay jointing tape LU-05Fix the underlay to the floorOn a timber floor, staple the underlay down every 100–150mm around the edges and along the joins, using a staple gun. On a solid concrete floor, use a suitable underlay adhesive spread in a thin layer instead of staples. Before stapling near the walls, use a detector to check for cables and pipes under the floor near the skirting — a detector can still miss deep or shielded cables, so staple with light taps and stop immediately if a staple meets unexpected resistance.
1 5kg tub · Underlay adhesive LU-06Trim the edges neatlyTrim the underlay flush with the inner edge of the gripper rods using a sharp utility knife, working in short, controlled cuts. Don't cut over the rods themselves — leave that small gap clear so the carpet can be tucked down against it later.
LU-07Tidy up and check you're ready for the carpetVacuum up any dust, staples or offcuts from the floor, and bag up waste underlay for disposal. Walk the room and check every join is taped, every edge sits inside the gripper rods, and nothing is lifting — any lumps or gaps will show through the finished carpet.
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