Plumbing

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How to: Remove Leaking or Mouldy Shower Silicone - Part One

2nd December 2022

One of the most depressing sights in a bathroom is leaky or black, mouldy silicone. Fortunately it is one of the easiest things to fix too. If your silicone has gone black with mould you may be able to get high strength cleaner to fix the problem. However, it may be cheaper and more effective to just call it quits and get your silicone replaced. If your shower is leaking, silicone replacement is definitely the way forward. Here’s what you need to know.

Tools

You don’t have to have a toolkit fit for a professional bathroom fitter to do the job properly, but basic tools will help. These include: mould spray, a silicone and grouting profiling kit, a silicone remover, plastic scrapers, scrubbing brush, kitchen towel, meths, hair dryer, clean and dry cloths, silicone.

Eliminate limescale

As with many DIY jobs, prepping your surface is one of the most important elements. Before you reseal, you need to make sure that the surface is clean and dry. This includes getting rid of any limescale, as it won’t be possible for your new silicone to form a good bond to the surface if you have limescale. While there are lots of expensive products on the market, limescale can actually be dissolved using vinegar. Be aware that limescale can damage chrome or aluminium, so before you go dousing your shower and fittings in vinegar, check it on a small area first. Apply vinegar and leave for half an hour. Once your time is up, see if you can easily wipe or scrape the limescale away without scratching the surface. If you can, great! If you can’t, try again but leave it for a little longer. If the vinegar damages or dulls the surface, you may have to rethink your options (or cap the length of time that you leave the vinegar).

Remove the existing silicone

Once you have banished limescale, you can start tackling the silicone. If even the tiniest spec of silicone remains, you won’t get a decent seal on the new silicone, which will result in leaks. There is no way of getting around this process and, be warned, it is laborious. Sealant remover can make the job slightly less arduous; apply it up to an hour beforehand and it will do a lot of the hard work for you. Once your silicone has softened, use your scraper to get the bulk of the silicone off. A plastic scraper is pretty effective and is less likely to damage your bath or shower tray than a metal one. Once most of it is off, give the surface a once over with a cloth, then go back over and remove the stubborn specks.

Once your silicone is removed, you are ready to clean down and get siliconing! Follow Trust A Trader on Facebook or Twitter for next week’s instalment, which covers the importance of clean surfaces, and how to get a professional finish. Can’t do it yourself? Check out our directory of bathroom fitters and handy people who will be able to help.

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Find clear, practical answers to common plumbing questions, helping homeowners understand everyday issues, know what checks they can carry out safely, and when it is best to contact a qualified professional.

What should I do if I have a blocked drain or sink?

Start with a plunger - create a good seal and use firm, steady pressure. For a kitchen sink blocked with grease, bicarbonate of soda followed by vinegar can help. If that's not shifting it, a drain snake reaches further down the pipe. Go easy on chemical drain cleaners as they can damage older pipes and rarely sort the root cause. If the blockage keeps coming back, affects more than one outlet, or you're getting unpleasant smells, call a plumber rather than trying to patch up the problem.
How can I tell if I have a hidden water leak?

The most obvious clue is a water bill that's gone up without any change in your usage. Beyond that, listen out for running water when everything's turned off, and watch for damp patches on walls or ceilings nowhere near an obvious water source. A quick self-test is to turn everything off and watch your water meter - if it's still moving, there's a leak somewhere. Tracking down exactly where it is usually needs a specialist detection kit, which a plumber can bring in without having to rip everything up.
What should I do if I have a burst pipe?

Turn off your stopcock straight away - you'll usually find it under the kitchen sink or where the mains water enters the property. Once it's off, open your taps to drain what's left in the system, switch off the boiler if you can do so safely, and mop up any standing water before it reaches electrics or flooring. Then call a plumber. With burst pipes, the faster you act, the less damage you'll be faced with.
What is a gas safety certificate and do I need one?

A Gas Safety Record is issued by a Gas Safe registered engineer after checking that all your gas appliances, flues, and pipework are safe. Landlords in England, Scotland, and Wales are legally required to get one every year and give tenants a copy within 28 days. For homeowners it's not a legal requirement, but getting a check done alongside your annual boiler service is a smart idea, particularly in older properties. Only a Gas Safe registered engineer can carry out the work or issue the certificate - you can check anyone's registration on the Gas Safe Register website.
Why is my water pressure low and can a plumber fix it?

Low pressure usually comes down to one of a handful of things: a stop valve that's not fully open, limescale build-up in older pipes, a failing pressure-reducing valve, or an issue with your water provider's mains supply. In most cases a plumber can sort it - though if the problem is with the mains itself, you'll need to contact your water company first. Either way, don't just live with it - ongoing low pressure can sometimes point to something more serious.
How do I know if my boiler needs replacing or just repairing?

If it's under ten years old and it's one specific fault, a repair usually makes sense. If it's over fifteen, has needed multiple fixes recently, is making strange noises, or your energy bills have crept up for no obvious reason - replacement is probably the better investment. A useful rule of thumb: if the repair would cost more than half the price of a new boiler, it's probably time to replace it.
How often should I get my plumbing inspected?

There's no legal requirement for homeowners, but every two to three years is a sensible habit - especially in older properties or hard water areas where limescale builds up over time. Your annual boiler service covers some of the associated pipework too. And if anything seems off between inspections - odd noises, discoloured water, unexplained damp - don't wait. Get it looked at sooner.
Why do my pipes make a banging or knocking noise?

That banging sound (sometimes called water hammer) usually happens when water flow is suddenly stopped or redirected, sending a pressure wave through the pipes. It's most common after flushing the toilet, shutting a tap sharply, or when a washing machine valve closes. Pipes that aren't properly secured can also knock against walls or joists. It sounds alarming but it's often an easy fix - a plumber can figure out whether it's a pressure issue, a faulty valve, or just some loose pipework.

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