How do I fix a carpet that has rucked up in waves?

A fitted carpet is held by gripper rods with angled pins and stays flat because it is stretched between them. When the backing relaxes — from humidity, from heavy furniture being dragged, or from having been fitted without enough tension — the slack shows up as waves.

What you'll need

• A knee kicker, or a hired power stretcher
• A bolster or a stair tool
• Pliers
• A sharp carpet knife
• Gripper rod and nails, if replacing
• Knee pads

Step by step

1. Work out why it happened.A carpet fitted without a stretcher, a very humid summer, underfloor heating, or furniture dragged across it. Fitting error is the most common, and it means the whole room needs restretching, not one edge.
2. Clear the room completely.Everything out, including anything heavy in the corners. You cannot stretch a carpet that is pinned down by a wardrobe.
3. Decide which walls to release.Stretch is applied across the ripples. Release the carpet along the wall the ripples run parallel to, and stretch towards it.
4. Release the edge.Pull the carpet off the gripper pins by hand or with pliers, working along the wall. Fold the loose edge back so you can see the gripper and the underlay.
5. Check the gripper.Rods that have come loose, rusted or lost their pins cannot hold a stretched carpet. Replace any bad sections before stretching.
6. Check the underlay while it is open.Underlay that has broken up or crumbled offers no support and makes the carpet wear quickly. It is much easier to replace now than later.
7. Hire a power stretcher for a whole room.A knee kicker is for tucking edges and small adjustments. A power stretcher braces across the room and takes out ripples a knee kicker cannot reach.
8. Stretch from the fixed side.Work from the wall that is still hooked on, across the room, in overlapping passes rather than one big pull in the middle.
9. Hook it on as you go.Press the stretched carpet down onto the gripper pins with a bolster while the tension is held, then move along.
10. Tuck the edge into the gully.The gap between the gripper and the skirting. A bolster or stair tool pushes the edge down into it, which is what gives a fitted carpet its clean line.
11. Trim the excess.Only after it is hooked on and tucked. Trimming first removes the material you need to grip. Cut with the blade angled into the gully.
12. Refit doorway edges.Under a threshold bar or into a carpet edge trim, so the stretched carpet is held at the doorway too.

Tips

• Hiring a power stretcher for half a day costs very little and is the difference between the ripples going and coming back in a month.
• Wear knee pads. Half of this job is spent kneeling on a gripper rod, which is exactly as unpleasant as it sounds.
• If the carpet has been rucked and walked on for a long time, the backing may have creased permanently and a faint line may remain.

Common mistakes

• Using a knee kicker to stretch a whole room — A knee kicker moves the carpet a short distance from the edge and cannot develop tension across a room. Ripples in the middle simply move somewhere else, and the carpet relaxes again quickly.
• Trimming the carpet before hooking it on — The excess along the wall is what you grip and stretch against, and it is what tucks into the gully to hold the edge. Cut it off first and the carpet cannot be tensioned or finished.

If it doesn't work

Questions people ask