Temporary pipe repair clamps, wraps and tape

A split pipe at night, a pinhole in the airing cupboard, a joint that has started to weep after a frost. Emergency repair clamps, wraps and tapes are sold for this moment. They can slow or stop a leak long enough for a plumber to arrive. They are a temporary repair, not a permanent joint, and none of them should be left in place for years and forgotten.

This page is about cold and hot water pipes. It does not cover gas. If a pipe might be a gas pipe, or you can smell gas, do not touch it and do not put a clamp on it. Leave the area, and follow when to call a Gas Safe engineer, which gives the emergency route. We give no method for any work on a gas pipe.

Turn the stopcock off first

Turn the stopcock off first. A clamp is not something to fight a full jet of mains water with. Close the stopcock, or the isolation valve on that pipe if there is one and you are sure it feeds the leak. Then open a cold tap at the kitchen sink to let pressure out of the pipe. Where the stopcock usually sits, and how to check it really has closed, is in find a leak and the stopcock.

In a house with a loft cold water tank, closing the stopcock stops the mains. It does not stop the tank emptying through a pipe it feeds. Running the bathroom taps can lower the tank faster, so less water is left to escape. If the leak is on a hot pipe, switch off the immersion heater or the heating at the controls you normally use, and let the pipe cool before you hold anything against it.

If water is near sockets, lights or a consumer unit, keep clear and do not touch switches with wet hands. Water through a ceiling has its own first steps in water coming through a ceiling. Any damage to electrics needs a qualified electrician. We do not give wiring instructions.

What the products are

Repair clamps. Usually a hinged metal or plastic collar with a rubber lining, closed by a screw or a lever around the pipe. Clamps are sized to the pipe, so a 15mm clamp will not hold on a 22mm pipe. They suit a split or a pinhole on a straight length. They do not suit a leaking joint, a bend, or a pipe that has bulged.

Repair wraps. A resin-soaked tape or a putty and sleeve that sets hard around the pipe. These often need a dry pipe and some time to cure before the water goes back on. The maker's instructions decide how long, and how much pressure the wrap is said to hold.

Self-amalgamating and repair tape. Tape that bonds to itself when stretched. It can slow a small weep while you wait. On a pipe at mains pressure it is the weakest of the three.

None of these replaces a properly made joint. A clamp can creep, a rubber lining can age, and a wrap over a corroded pipe can let go when the corrosion spreads. A pipe that has split once from frost often has damage nearby that you cannot see.

Using one as a stop-gap

Read the instructions on the pack. Then, in general terms:

• Dry and clean the pipe as far as you can, so you can see the full length of the split.
• Centre the clamp or wrap on the damage with some margin either side.
• Close it as the maker describes. Do not keep forcing it on a soft plastic pipe, which can crush.
• Turn the stopcock back on slowly and watch it for several minutes, with a towel and a bowl underneath.
• If it still drips, turn the water off again and leave the pipe for a plumber.

A clamp on a push-fit or compression joint usually will not seal, because the shape is wrong. Joints have their own fixes, covered in push-fit vs compression vs solder. Leave those to a plumber if you are unsure.

After a freeze

Frost is the most common reason people reach for a clamp. Thaw the pipe gently before any repair: frozen pipes explains why a naked flame is never the answer. A pipe that has split in one place may have weakened further along. When the water goes back on, check the whole run, not just the clamp.

Getting it fixed properly

Book a permanent repair as soon as you can. Tell the plumber what the clamp is covering and how long it has been on. Hiring a plumber covers what to ask. Photograph the damage and the clamp before the repair if you may claim: see leak insurance claims. An insurer may ask when the leak started and what you did about it.

If the leak is on central heating pipework next to the boiler, or on anything inside the boiler, do not put a clamp on it yourself. Turn the water off if you can, and call a plumber or, for anything on the gas appliance, a Gas Safe registered engineer.

Is a pipe repair clamp a permanent fix?

No. A clamp, wrap or tape is a temporary repair to stop or slow a leak until the pipe can be repaired properly. Book a plumber to cut out the damaged section and make a proper joint.

Can I fit a clamp with the water still on?

Turn the stopcock off first and open a tap to release pressure. A clamp fitted against a full flow is hard to place, rarely seals and can spray water over electrics.

Can I use a repair clamp on a gas pipe?

No. Do not touch a gas pipe or put any clamp, tape or wrap on it. If you smell gas, leave and use the emergency route on our Gas Safe page. Gas work is for a Gas Safe registered engineer only.