Why is your radiator tapping? Here we explain the most common causes and quick fixes.
Noticing that your radiator is making tapping noises? One thing we know for sure: those aren’t leprechauns fighting their way out.
While these sounds can be totally benign, it’s also possible that they indicate an issue with your radiators or/and heating system as a whole.
Whatever the case, you’ve come to the right place. We’re experts in tapping sounds, especially coming from your radiators (and experts in all things heating).
In the following guide, we’ll discuss the most common causes of radiator tapping and how it can be fixed.
Let’s begin!
Common Causes and Fixes of Radiator Tapping
Note: All fixes listed below require hiring a heating engineer.
For the specific radiator noises raised in this article, just as with splitting atoms, there are no DIY-friendly solutions.
Please be aware that there are many other radiator sounds with other explanations.
In this guide, we are focusing solely on radiator tapping noises and their solutions.
As mentioned, there are many reasons why radiators may produce a tapping sound (or something closely resembling a tapping noise).
They range from benign and common explanations to those that will likely require hiring a professional to solve. And we mean a heating specialist, not a Morse code aficionado to decipher the messages.
Without further ado, let’s explore the most common causes of radiator tapping and the solutions.
Poorly Fitted Thermostatic Radiator Valves
Among the most common reasons for a tapping radiator is an incorrectly installed thermostatic radiator valve or TRV.
Among the potential causes of this include that a worn-down TRV nearly closes off upon cooling, leading to internal parts vibrating.
It’s also possible that the TRV has been fitted to the wrong end entirely - perhaps as the result of a DIY project or the world’s worst April Fool’s prank.
What's the Solution?
If you suspect this is the issue, be sure to hire a professional to re-fit the TRV.
This should fix the issue. However, if it doesn’t, it potentially means there is another issue at hand. Luckily, you already have a professional in your house to go through the other options.
Radiator Metal Expanding and Contracting
One of the most common reasons that your radiator (as well as the rest of your heating system) will produce tapping or clicking sounds is due to the metal expanding and contracting.
When your boiler fires up, you may quickly notice tapping sounds coming from one or more locations.
These sounds may be coming from exposed pipework, the pipes inside your walls or/and from your radiators. In other words: tapping noises everywhere.
These tapping/clicking noises can result from metal expanding as hot water begins to flow through your pipework and into the radiators.
Moreover, once your heating turns off, the water inside the pipework and radiator will begin to cool down.
As a result, the cooling of this water could cause your radiator’s metal to contract. The same can apply to the metal that makes up your heating system pipes. Metal produced by Black Sabbath has other tapping noises, caused by Bill Ward.
If you only notice the sounds soon after you’ve turned your heating on or/and shortly after your heating has turned off, it’s very likely that the metal in your radiators is simply expanding and contracting.
With that being said, if you want absolute certainty, you can always call out a Gas Safe Register engineer to verify that this is the case.
After all, it is a possibility that incorrectly secured pipework is the issue (more on that later).
What's the Solution?
You could stop using your heating system, but that’s usually not a solution people choose. If these tapping sounds are not annoying you, then there is nothing to solve.
However, if they are particularly loud or otherwise bothering you, hire a heating engineer to have a look (or rather, a listen).
With that said, it’s unlikely they’d be able to offer a solution other than recommending that you have your pipework or/and radiator replaced.
It’s important to note, however, that some level of noise from radiators and heating system pipework is to be expected.
A build-up of Limescale or Heating Sludge
It’s also possible that an accumulation of limescale or heating sludge is causing your radiators to become noisy.
The sounds you should hear in these would not be quite tapping noises, but more likely rumbling or/and banging sounds. Like you’ve awakened a Balrog and it’s time to get out. Fly, you fools.
Okay, don’t worry. It’s not a Balrog. The rumbling noise you may hear is called kettling.
As for the banging sounds, even if you hear this coming from your radiator, it would actually be coming from your boiler and echoing through your radiator.
Whatever the case, limescale and heating sludge can both be addressed by a professional.
What's the Solution?
If there is limescale present, you’ll need to hire a heating engineer to perform a power flush (if you think your toilet needs one of those, call a plumber instead).
That will remove the limescale from your heating system.
However, if you live in a hard water area, you should take steps to prevent limescale re-accumulating in the future (e.g., have a water softener or limescale reducer installed). If your water is hard to the touch, you’re probably handling ice cubes.
Please note that some boiler manufacturers' warranties stipulate that the warranty is invalidated if a water softener is used or installed, so always check this before installation.
When it comes to heating sludge (a gradual collection of rust within your heating system that has mixed with water), a power flush will also suffice to get rid of it.
Once again, this must be dealt with by a professional. Having a suitable central heating inhibitor added to your heating system by a professional will help prevent sludge from forming again in the future.
Incorrectly Secured Pipework
If your heating system’s pipework has not been clipped to the wall correctly, vibrations may result in a range of sounds coming from your pipework and radiators. None of it would fit in Night of the Proms, however.
You might notice hammering or vibrating noises coming from your radiators.
Vibrations can echo through and out of the radiator (as touched on already), hence incorrectly secured pipes may result in noisy radiators. Hushing them won’t help, either.
Given that incorrectly secured pipework is more likely to produce noise when water is flowing through, these sounds may become more prominent after your heating has just turned on.
So you can see how this could be confused with the sounds of metal expanding soon after your boiler has fired up.
If the pipework featured in your heating system has not been clipped to the wall correctly, vibrations can result in various sounds coming from the pipework and your radiators alike.
You may notice vibrating or hammering sounds coming from your radiators.
What's the Solution?
Hire a heating engineer or even a plumber to re-secure your heating system’s pipework.
Cost of Having Radiator Tapping Fixed by a Heating Engineer
The average cost of hiring a qualified heating engineer in the UK is £30 to £60 per hour.
Labour prices can vary depending on where you live.
For example, heating engineers tend to charge more in the southeast of England when compared with areas such as the north of England, Scotland, and Northern Ireland. Labour prices are even cheaper in places like China and the Philippines, but having a plumber flown in usually negates the lower labour cost.
Of course, the overall cost of having a radiator tapping issue solved will also include the price of supplies.
The average costs of hiring a professional to solve radiator tapping noises:
Power flush – £400 to £800
Re-securing pipework – £130 to £320
Also, to prevent future limescale, here are the estimated costs:
Adding a water softener – £250 to £1,500
Chemical limescale reducer – £10 to £50
Fitting a magnetic or electronic descaler – £50 to £300
Lastly, to prevent heating sludge, here is the likely price tag:
Adding central heating inhibitor – £40 to £100
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