Radiators Ticking or Creaking When the Heating Comes On

A radiators ticking noise when the heating comes on, or a creak as it cools down, is almost always thermal expansion. Copper pipes and steel radiators grow slightly as hot water reaches them and shrink again as they cool, and where they rub against a joist, a floorboard, a pipe clip or a wall bracket they stick and slip, giving that tick-tick sound. It is usually harmless. You can often quieten it by finding the spot where the pipe is rubbing and giving it room to move.

This guide is about ticks, clicks and creaks from radiators and pipework. If the noise is coming from the boiler itself, such as kettling, whistling or a bang on ignition, our boiler noise glossary covers those sounds.

Why radiators and pipes tick when the heating comes on

Metal expands when heated. Copper grows by roughly 0.017mm per metre for every degree Celsius it warms up. That sounds tiny, but heating pipes go from room temperature to well over 60°C in minutes. A 5-metre run of copper warming by 50°C gets around 4mm longer.

If the pipe could slide freely, you would never hear it. In real houses it passes through notches cut in floor joists, sits in tight plastic clips, and is held at the radiator by valves screwed onto a heavy steel panel. As it grows, friction holds it still until the force builds up enough to make it jump. Each jump is a tick. Hundreds of small jumps along a long run sound like a clock or someone tapping under the floor.

Radiator manufacturer Stelrad gives the same explanation in its guide on how to stop radiators clicking, listing thermal expansion first, followed by trapped air, limescale and pipes pressing against joists or floorboards.

Common sources of ticking and creaking

Radiator noise at night and when the heating goes off

Many people only notice the noise in bed. Two things are going on. The house is quiet, so small sounds stand out. And night is when big temperature changes happen: the timer switches the heating off at bedtime, every pipe cools and contracts, and then it all heats up again early in the morning.

Contraction can be noisier than expansion, because pipes cool unevenly. If ticking keeps you awake, try a smaller night-time drop. Setting the room thermostat back by a few degrees overnight, rather than turning the heating fully off, means the pipes do not swing between cold and hot so sharply. Our article on whether to leave the heating on low all day covers the trade-offs.

How to find where the ticking is coming from

Expansion noise travels along pipework, so the sound often seems to come from somewhere it is not. A methodical approach saves lifting the wrong floorboards.

1. Start from cold. Let the system cool fully, then switch the heating on and listen as the hot water spreads.
2. Follow the warmth. The noise starts where the pipe is heating. Feel along exposed pipes and note which ones are warming when the ticks begin.
3. Listen at floor level. Lay your ear on the floor or hold a screwdriver handle to your ear with the tip on a floorboard. The sound is loudest above the tight spot.
4. Check the radiator first. Watch the brackets as it warms. If the creak comes from the hangers, it is the panel moving.
5. Mark the spot with tape so you, or an engineer, can go straight to it.

How to stop radiators ticking and pipes creaking

Most fixes are about giving the metal room to move. Some are simple; others mean lifting floors, which you may prefer to leave to a heating engineer or carpenter.

Easy fixes you can try

• Bleed the radiators. Trapped air can cause clicks and gurgles. Follow our guide on how to bleed your radiators, then check the boiler pressure.
• Move furniture that is pressing against a radiator or exposed pipe.
• Fit foam pipe sleeves to exposed pipes where they touch walls or each other.
• Check radiator brackets. A felt or plastic pad between the radiator hanger and bracket can stop a creak. Only lift a radiator off its brackets if the valves allow it to move without straining the pipe joints.

Fixes under the floor

• Widen tight joist notches slightly, within the limits that keep the joist structurally sound.
• Pack the notch with felt or a section of foam sleeve so the pipe slides instead of sticking.
• Swap tight clips for ones with rubber linings, or space them so the pipe can expand.
• Separate crossing pipes so flow and return do not rub together.

Be careful lifting boards. Gas pipes and electrical cables often share the same void as heating pipes. If you see a yellow-labelled or different-sized pipe and are unsure what it is, stop. Drilling or nailing into a pipe is a real risk, and our guide on what to do if you have drilled into a gas pipe explains the emergency steps.

Lower the flow temperature

The hotter the water, the more the pipes expand and the faster they do it. Many condensing boilers run hotter than they need to. Turning the radiator flow temperature down, where your home stays comfortable, reduces the movement and often makes noises quieter. See our guide to boiler flow temperature settings. Weather compensation, which adjusts the flow temperature to the outside temperature, gives gentler warm-ups too.

Noises that are not expansion

Ticking and creaking are the harmless end of heating noise. These sounds point to something else:

• Gurgling or trickling in radiators: air in the system, or low pressure.
• A loud bang when a tap or valve closes: water hammer. See our guide to water hammer and banging pipes.
• Rumbling or kettle-like boiling from the boiler: scale or sludge on the heat exchanger, known as kettling.
• Constant whooshing or rushing through pipes: water moving very fast, sometimes from pump settings or partly closed valves.
• Tapping that gets louder over weeks, especially with cold spots on radiators: possible sludge or limescale, which Stelrad notes can restrict flow.

Pump settings, bypass valves and anything inside the boiler should be adjusted only by a Gas Safe registered engineer. Our central heating service includes tracing noises like these.

Quieter heating this winter

Ticks and creaks are your heating doing its job noisily rather than failing. Bleed the radiators, look for tight spots, cushion the pipes and consider a lower flow temperature. If the noise is not ticking but banging, gurgling or rumbling, or you cannot find the source, it is worth having it looked at.

Gasmaster’s Gas Safe registered engineers trace heating noises and fix the causes across Stoke-on-Trent, Staffordshire, Cheshire and Derbyshire. Get in touch to book an engineer or arrange a service.

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