Repair loose grouting in the bathroom in Hong Kong

The grouting between my bathroom tiles and the silicone around the sink and bath are loose in places. How do I renew them?

Using a utility knife, can opener or ideally specially designed grout tool, scrape out all the loose grout and remove all the silicone seals. Mix a new batch of grout (HK$45 per 2kg bag), according to the manufacturer's instructions, then fill in all the gaps with a sponge or squeegee held at a 45-degrees.

Using the handle of an old toothbrush, smooth along the grout joints, then clean off any excess grout from the tiles before it dries. Once dry, polish the tiles with a damp cloth.

To replace new seals, carefully run a bead of silicone around the sink and bath using a silicone gun. Before it cures, steadily run a wet finger along the top of the silicone to create a smooth seal. Don't press too hard. If you have sensitive skin, wear rubber gloves and don't use the bath or sink until the silicone is fully cured. All tools and materials are available from Yuen Fat Ho, 77 Hollywood Road, Central, tel: 2546 8020.

Why Does Grout Fail So Quickly in Hong Kong?

If you have lived in Hong Kong for any length of time, you will have noticed that grouting deteriorates far faster here than it would in, say, London or Sydney. There is a simple reason for this: the relentless humidity cycle that our bathrooms go through.

During the hot, humid months from April through September, indoor humidity regularly exceeds 85-95%. Your bathroom is already a wet environment, and when you add Hong Kong's ambient moisture to the steam from hot showers, the grout is essentially never fully dry for months on end. This constant dampness causes standard cement-based grout to soften, crumble, and eventually fall out.

The problem is made worse by the temperature swings between air-conditioned rooms and un-air-conditioned bathrooms. When you cool one room to 22 degrees and the bathroom next door is sitting at 30 degrees with 90% humidity, condensation forms on every cool surface. That condensation seeps into the grout joints and accelerates the breakdown.

Here is what I recommend to combat this:

• Use epoxy grout instead of cement-based grout: Epoxy grout (around HK$80-120 per kg) is waterproof, stain-resistant, and far more durable in humid conditions. It is harder to work with than standard grout and sets faster, so you need to work in small sections. But it will last three to five times longer in a Hong Kong bathroom. Brands like Laticrete SpectraLOCK and Mapei Kerapoxy are available from specialist tile shops in Wan Chai.
• Run the bathroom exhaust fan for 15-20 minutes after every shower: This simple habit makes a massive difference to grout longevity. If your exhaust fan is weak or broken, replacing it is one of the best investments you can make.
• Wipe down tiled surfaces after bathing: A quick wipe with a squeegee (HK$20-30 from Japan Home Centre) removes standing water from grout joints before it can soak in.

What Tools Do You Need for DIY Regrouting?

Regrouting is one of those jobs that looks simple but benefits enormously from having the right tools. Here is your complete shopping list, all available from hardware shops like Yuen Fat Ho in Central or Wing Lee Hardware on Wellington Street:

• Grout removal tool or utility knife: HK$15-40. A dedicated grout saw with a carbide blade makes the job much easier than a standard knife. For larger jobs, a multi-tool with a grout removal attachment (HK$200-400) saves hours of work.
• Rubber squeegee or grout float: HK$20-50. Essential for pressing grout into joints at the correct 45-degree angle.
• Mixing bucket and paddle: HK$15-25. Mix only small amounts of grout at a time, as it begins to set within 20-30 minutes.
• Grout (2kg bag): HK$35-55 for standard cement grout, HK$80-120 for epoxy grout. A 2kg bag is enough for roughly 4-6 square metres of standard wall tiles.
• Silicone gun and cartridge: HK$25-40 for the gun, HK$30-60 for a quality silicone cartridge. Use a bathroom-grade anti-mould silicone.
• Sponge and clean cloths: HK$10-20. For wiping excess grout and final polishing.
• Old toothbrush: Free. Surprisingly useful for smoothing grout joints and cleaning up edges.

One thing I should mention: before you start removing old grout, check the condition of the tiles themselves. If tiles are cracked or loose, they need to be dealt with first. Regrouting around a damaged tile is a waste of your time and materials because the grout will fail again where the tile is moving. Similarly, if you are thinking about whether to retile over old tiles or replace them entirely, make that decision before you invest time in regrouting.

When Should You Call a Professional?

Basic regrouting is a satisfying DIY job and well within most people's capabilities. However, there are scenarios where professional help is the smarter choice:

• Extensive grout failure across large areas: If more than a third of the grouting in your bathroom has failed, this often indicates an underlying moisture problem rather than simple wear and tear. A professional can assess whether there is water penetration behind the tiles.
• Black mould in grout joints: Surface mould can be cleaned and regrouted. But if mould keeps returning despite treatment, it usually means moisture is getting behind the tiles. This needs investigation before regrouting.
• Grout failure around the shower tray or bath: These are the most critical seals in your bathroom. If water gets behind the bath or shower, it can cause serious damage to the floor structure and even leak into the flat below. Getting a watertight seal here is essential.
• If you want a colour change: Changing grout colour across an entire bathroom is a big job that requires complete grout removal. A professional with power tools can do this in a fraction of the time it would take with a manual grout saw.

For more advice on keeping your Hong Kong bathroom in top condition, check out our tips on hanging accessories without drilling tiles and browse our full bathroom guides.

Last updated: March 2026