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

9th December 2022

Silicone doesn’t just look good in a bathroom, it plays a vital role, preventing water from seeping out into the wall or floor behind the tiles. As it is constantly subjected to water and products, silicone can quickly become stained or build up mould. At this point, it no longer looks clean and fresh, but grubby and dingy. There is a point at which no amount of bleach, elbow grease or specialist products can save your silicone; you will have to replace it.

Last week, we looked at the importance of getting rid of limescale before you start removing the existing silicone. Assuming you have recovered from one of the most boring jobs known to the DIY-er, and have removed every trace of the previous silicone, even the most stubborn specks, you can proceed with the job.

Clean surfaces

Your surface prep isn’t done when the silicone is removed. The next step is to thoroughly clean and dry the surface before giving it a once over with methylated spirits to get rid of the most stubborn grime.

Getting ready to silicone

Before you start, make sure that every surface you will be working with is completely dry. Even the tiniest bit of moisture will repel your silicone and prevent you from getting an effective seal. Once it is dry, you are ready to get going! You will need your silicon, and a silicone profiler or profiling kit. A sealant gun will help you to get the sealant where you want it, minimising mess and wastage.

Before you start, read the instructions on the sealant. You may think that you have got everything covered but it is really important that you know how long you need to cure your sealant for. If you get it wet too soon, all that hard work will be wasted and you will have to start again.

Applying sealant

If you are using a sealant gun, make sure that you have the right aperture size for the job. Apply a steady band of sealant around the shower tray or bath tub, stopping as often as you need to keep the flow even. Once you have completed a small section, use paper towels to wipe away the excess, before carrying on the next section. Once you have completed a full length, use your profiling kit and apply steady pressure, dragging the profiler along the length of the tray or tub. Don’t push to hard or you may create a break in the silicone. If you notice a bubble or gap, go over it gently until you have a smooth finish. Once you have finished, leave it to dry for at least as long as recommended in the instructions (usually 24 hours at least), and you should have a clean, mould-free, leak-free silicone! Need help? If you are not confident doing DIY yourself, head to our directory where you can find local, rated tradespeople in your area. And don’t forget to follow Trust A Trader on Facebook or Twitter.

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Looking for more plumbing advice?

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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