How to Fix Crack in Bathtub: A Complete Guide

Bathtubs aren’t meant to crack. They’re supposed to be sturdy, smooth, and sealed tight. So when a crack suddenly appears—maybe while you’re stepping in, maybe while cleaning—it can feel like the whole bathroom’s turning against you. But don’t panic just yet. A crack in your bathtub doesn’t have to mean total replacement or a plumbing nightmare. With a bit of patience (and the right know-how), you can fix it yourself.

We’ve pulled together everything you need to know about repairing a crack in a bathtub—whether it’s hairline or deeper, on acrylic, fibreglass or something in-between. Let’s get into it.

What Causes A Crack In Your Bathtub?

Cracks can appear for all sorts of reasons. Sometimes it’s age. Other times it’s poor installation or even just general wear and tear (baths do a lot of heavy lifting, after all). One common cause is movement—if your tub isn’t properly supported underneath, it can flex every time someone gets in. That flexing leads to stress fractures. Give it enough time, and boom: a crack.

It’s also worth considering the material. Acrylic and fibreglass tubs are popular because they’re lightweight and affordable—but they’re also more prone to cracking compared to heavier options like enamelled cast iron. Nothing’s perfect.

Is It Safe To Use A Bathtub With A Crack?

Short answer: not really. A small crack might not look like a big deal, but water has a sneaky way of getting into places it shouldn’t. If water seeps through the crack, it can damage the subfloor, encourage mould growth, or cause structural issues over time. Even worse? What starts as a tiny flaw can quickly grow under pressure.

So yes, repairing the crack in your bathtub promptly is definitely the way to go.

Can You Fix A Crack In A Bathtub Yourself?

We think so—especially for small or surface-level cracks. If you’re even mildly handy and don’t mind getting your hands a little dirty (and possibly smelling like epoxy for an afternoon), there’s a good chance you can do this on your own.

You’ll find repair kits that are made specifically for the job. They often include everything from filler paste to sandpaper, colour-matching paint and sealants - and you don’t need a full toolbox—just some care and a bit of elbow grease.

Step-By-Step: How To Fix Crack In Bathtub

Step 1: Clean And Dry The Area

Before anything else, give the damaged spot a thorough clean. Use a mild detergent or non-abrasive cleaner to remove any grime, soap scum, or oils. Rinse well, then let it dry completely. Moisture and filler materials do not mix.

Step 2: Sand The Surface

Next, lightly sand the area around the crack using the sandpaper included in most repair kits (or fine-grit paper if you’ve got some lying around). This helps the filler bond better to the tub surface. You’re aiming for slightly rough—not destroyed.

Step 3: Apply The Filler

Follow the instructions in your repair kit to mix and apply the filler or epoxy resin. Use the spatula or applicator tool provided to press it into the crack and smooth it over. Be generous, but not sloppy—you want full coverage without a giant mound.

Step 4: Let It Cure

This part is crucial. Don’t rush. Let the filler dry and cure for as long as the instructions recommend. It’s usually at least a few hours (sometimes overnight). Play it safe. No one wants to redo the whole thing because it got poked too early.

Step 5: Sand And Paint

Once cured, sand it again to smooth it out and blend it with the rest of the tub. Then, if your kit includes touch-up paint, apply it in thin layers to match the original finish. You may need a couple of coats depending on the colour.

Step 6: Seal It (If Needed)

Some kits include a clear coat or sealant. This step isn’t always mandatory, but it does add an extra layer of protection and polish. Think of it like the top coat on nail varnish—it makes things last longer and look better.

What If The Crack Is Too Big To Fix?

If you’ve got a major fracture, or if the crack keeps coming back after repairs, it might be time to replace the bathtub entirely. No one wants to hear that, but there’s a point where DIY stops being worth it.

On the plus side, a new bathtub can totally refresh your space. Pair it with some fresh panels while you’re at it—feel free to browse panel styles for modern bathrooms on our website if you’re looking for inspiration.

How Do You Stop Bathtub Cracks From Coming Back?

Start by checking the support underneath the tub. If it moves even slightly when someone steps in, you’ve got a problem. Reinforcing the base or ensuring it’s level and properly fitted can make a huge difference.

Also, try to avoid heavy impacts. Dropping a shampoo bottle from shoulder height might seem harmless, but over time, those little knocks can add up. Think of your bath like a ceramic mug: fine with gentle use, but not invincible.

When Should You Call A Professional?

If the damage is structural, widespread, or just plain weird-looking, it’s best to get a pro involved. Some cracks hide deeper problems (like leaks you can’t see), and professionals have the tools and training to diagnose and fix them safely.

Also, if your tub’s still under warranty, attempting your own repairs could void it. Worth double-checking.

Final Thoughts

Fixing a crack in a bathtub isn’t rocket science. In many cases, a small repair kit, some careful prep, and a steady hand are all it takes to restore function and appearance. That said, know your limits. If the damage is too severe or you’re just not comfortable tackling it, don’t hesitate to call in the experts.

And if you’re planning a full refresh, why not go beyond the crack? From tub replacements to simple style upgrades, we’ve got you covered. Here’s how to make your bathtub look brand new.

Your bath deserves to be more than functional—it should be beautiful, too.