Author: Mark Studdert
Regrouting bathroom tiles is one of the most effective ways to restore a tired or deteriorating bathroom, especially in the shower, where grout works hardest. Cracked, crumbling, or mouldy grout is more than a cosmetic problem. It can be an early warning sign that moisture is getting where it shouldn’t.
If your grout is already failing, our professional regrouting service restores the tiled surface without removing tiles in most cases.
Mould and wet-area defects are common in Australian homes. Research indicates around one in three homes is affected by mould, and 35% of renters have experienced mould in their bathrooms. In apartment buildings, industry research found internal waterproofing problems in 28% of cases and tiling issues, including cracked or defective grout, in 25%.
Before regrouting, it’s important to understand why the grout failed. Replacing damaged grout without addressing the cause often means the problem comes back.
What Is Regrouting?
Regrouting is the process of removing old, cracked, mouldy, or deteriorated grout from between tiles and replacing it with new grout. It restores the look of the tiled surface, improves its resistance to water, and reduces the risk of moisture getting behind the tiles.
Regrouting can be done on shower walls and floors, bathroom floors, and wall tiles. In most cases, the existing tiles stay in place.
Signs Your Bathroom or Shower Needs Regrouting
The warning signs usually appear well before a serious problem develops. Look closely at the grout lines around corners, the shower floor, and the wall-to-floor junctions. Watch for:
- Cracked or crumbling grout. Cracks let water into the joint, and crumbling means the grout has lost its strength.
- Dark or mouldy joints. Mould that returns soon after cleaning often means moisture is sitting inside the grout.
- Missing sections of grout. Open joints leave tile edges and bedding exposed to water.
- Areas that stay damp longer. Grout that stays dark long after a shower is absorbing and holding water.
- Rough or eroded grout. Grout that has lost its smooth surface is more porous and harder to clean.
If grout is breaking down or pulling away from the tiles, don’t wait for a visible leak before acting.
When it may be more than a grout problem. Some signs suggest water is already escaping the shower:
- Loose or hollow-sounding (drummy) tiles
- Swollen skirting boards or door frames
- Stains or bubbling paint on walls next to the shower
- A persistent musty smell
Regrouting alone may not fix these, so have the shower inspected. Read more about water behind shower tiles and how to fix a leaking shower without removing tiles.
What Causes Grout to Crack?
Grout rarely cracks for no reason. Bathrooms are exposed to constant moisture, temperature changes and everyday movement, and over time these put stress on the grout. Corners and wall-to-floor junctions take the most strain, because that’s where movement concentrates.
Common causes include:
- Building or substrate movement
- Movement at changes of plane, such as corners and wall-to-floor joints
- Poor surface preparation or incorrect mixing during installation
- The wrong grout for a wet area
- Grout shrinkage as it cures
- Excessive moisture and general deterioration over time
- Previous poor-quality repairs
Once gaps appear, water can find its way into places it shouldn’t. Damp, damaged grout is also a breeding ground for mould and mildew, which can affect the health of everyone in the home.
If your tiles are already cracking read also is a cracked shower tile a major problem?
Can You Regrout Over Existing Grout?
Not if you want a lasting repair. New grout needs a clean, properly prepared joint to bond to. Spreading it over old, cracked grout usually hides the problem rather than fixing it, and the thin new layer tends to crack or lift.
For a result that lasts, remove the damaged grout to a suitable depth and thoroughly clean and prepare the joints before the new grout goes in.
What’s the Best Grout for Showers and Bathrooms?
For showers and other wet areas, epoxy grout is generally the best choice. It is highly water-resistant, doesn’t absorb moisture the way cement grout does, resists stains and chemicals, and doesn’t need sealing. Its colour also stays consistent, while cement grout can fade with cleaning.
Epoxy grout is not a substitute for the waterproofing membrane beneath the tiles, though. Choosing the right grout is only part of the job, and preparation and application matter just as much. For a detailed comparison, see our guide to cement-based grout vs epoxy grout. For fine cracks in tiles, read about using epoxy for shower tile hairline cracks.
Regrouting Bathroom Floor Tiles
Bathroom floors take foot traffic, cleaning chemicals, and regular water exposure, so floor grout often wears faster than wall grout. The process is the same: remove the damaged grout, prepare the joints, and regrout. Give extra attention to floor-to-wall junctions and the area around the shower entry, because these are common points of movement and water entry.
If floor tiles sound hollow when tapped, or grout keeps cracking in the same spot, the problem may be movement or loose tiles rather than the grout itself. Have it inspected before regrouting.
How Long Does Regrouting Take?
A standard shower regrout typically takes 2-4 hours, depending on the size of the area and the condition of the existing grout. You’ll usually need to wait 24 hours before using the shower so the new grout can cure properly. Your technician will confirm the exact time for the product used.
How Much Does Regrouting Cost in Australia?
Regrouting costs a fraction of a full bathroom renovation, which is why it’s worth doing before damage spreads. For a cost comparison, see shower tile repair vs full demolition.
The cost of regrouting depends on:
- The size of the shower or bathroom
- How much old grout needs removing, and how difficult it is to remove
- Whether the junctions need extra preparation or silicone replacement
- The type of grout used (epoxy costs more than cement grout but lasts longer in wet areas)
- Whether any underlying issue, such as a leak, needs repair
What We’ve Learned From Repairing More Than 100,000 Showers
With 28 years of experience, we’ve developed our regrouting process around proper preparation and long-term performance. Our proprietary DiamoSmart® preparation system is designed to thoroughly prepare the shower before we apply commercial-grade, mould-retardant epoxy grout. It’s this attention to what happens before the new grout goes in that helps us achieve a more durable result.
That experience is also why we’re confident enough in the products we use to offer a 25-year product warranty. For us, regrouting isn’t simply about making an old shower look new again. It’s about understanding why it failed in the first place and doing the job properly.
Need your bathroom or shower regrouted? Our shower and tile regrouting service covers Brisbane, Sydney, Gold Coast, Sunshine Coast, Central Coast and Newcastle. Get a free quote or call 1300 888 806.
FAQs
How often should bathroom grout be replaced?
There’s no fixed schedule. Replace grout when it starts cracking, crumbling, staying damp, or showing mould that won’t clean off. Well-installed epoxy grout in a well-ventilated bathroom lasts far longer than cement grout in a poorly ventilated shower.
Will regrouting fix a leaking shower?
It depends on the cause. If deteriorated grout is contributing, regrouting may be part of the repair. But leaks can also come from failed silicone, movement, plumbing or waterproofing problems, so the cause should be confirmed first.
Can you regrout just part of a shower?
Yes, small damaged sections can be repaired. But new grout may not match the colour of aged grout, and if one area has failed, others are often close behind. Regrouting the whole shower usually gives a more consistent, longer-lasting result.
Does new grout need to be sealed?
Epoxy grout doesn’t need sealing. Cement-based grout is porous and should be sealed after it cures, then resealed periodically.
Can cracked grout cause a leak?
Yes. Cracked grout can let water through damaged joints, and it may also point to movement or another underlying issue. Find out why it cracked before deciding on the repair.
About the Author:
Mark Studdert is the founder of The Shower Repair Centre, specialising in shower leak repairs, waterproofing, leak detection, and bathroom restoration. With over three decades of experience, he pioneered and patented the DiamoSmart® technology, helping save leaking bathrooms without tile removal in 95% of cases.
