How to Fix a Cracked Bathtub: A Simple DIY Guide to Save Your Tub (and Your Wallet)

Learn how to fix a cracked bathtub with this simple DIY guide! Save money, avoid replacement, and repair fiberglass or acrylic tub cracks like a pro in just a few easy steps.

A cracked bathtub doesn’t always mean you need to replace the entire thing—and thank goodness for that! Whether it’s a hairline fracture or a deeper split, you can repair a cracked bathtub at home without calling in the pros. With the right tools, a little patience, and this step-by-step guide, your tub can be good as new.

If you’re dealing with a fiberglass tub crack or any kind of acrylic or plastic bathtub damage, don’t panic. This DIY fix will help you patch it up, save money, and avoid a full-blown renovation.

What Causes a Cracked Bathtub?

Before we dive into how to fix it, let’s talk about why bathtubs crack in the first place. The most common causes include:

• Aging materials: Over time, fiberglass and acrylic can weaken.
• Improper installation: A tub that wasn’t properly supported can flex and crack.
• Heavy impact: Dropping something heavy (like a shampoo bottle or shaving mirror) can chip or fracture the surface.
• Temperature extremes: Rapid temperature changes may cause the surface to expand or contract too quickly.

Identifying the type of crack—surface-level, spiderweb, or deep structural—is key to determining the best repair method.

Tools and Materials You'll Need

Here’s your DIY cracked bathtub repair kit:

• Fiberglass repair kit (available at most hardware stores)
• Sandpaper (80-grit and 240-grit)
• Utility knife
• Rubbing alcohol or acetone
• Soft cloth or microfiber towel
• Putty knife or plastic spreader
• Paintbrush (for finishing gel coat, if needed)
• Respirator or mask (fiberglass dust isn’t your friend)
• Rubber gloves

Pro tip: Make sure the repair kit matches your tub’s material—acrylic, fiberglass, or enamel.

Step-by-Step Guide: How to Fix a Cracked Bathtub

Step 1: Inspect the Crack

Start by examining the crack. Is it just a surface scratch, or does it feel deep to the touch? Gently press on the area around it. If it feels spongy or gives under pressure, the crack may be more serious, and you’ll want to reinforce the area during the repair.

Step 2: Clean and Dry the Surface

Use rubbing alcohol or acetone to thoroughly clean the area. Remove soap scum, oils, or grime. Let it dry completely—moisture can ruin the repair.

Step 3: Sand the Damaged Area

Use 80-grit sandpaper to roughen up the cracked area and give the resin something to bond to. Go slightly beyond the edges of the crack (about 2 inches around). Wipe away dust with a damp cloth and let it dry again.

Step 4: Mix and Apply the Filler

Following the instructions on your fiberglass repair kit, mix the resin and hardener. Using a putty knife, apply the mixture to the crack, pressing firmly to fill it completely. Spread it evenly and feather out the edges for a smoother finish.

Let it cure for the recommended time (usually 1–2 hours).

Step 5: Sand and Smooth

Once it’s fully cured, sand it again with 240-grit sandpaper to smooth out the repair. If the surface looks uneven, repeat the filler and sanding steps until it blends in.

Step 6: Apply the Topcoat (Optional)

If your kit includes a gel coat or finishing paint, apply it with a small brush or sponge. This seals the repair and matches the shine of the rest of the tub. Let it dry thoroughly before using the bathtub again.

How Long Does It Last?

If done correctly, a DIY bathtub fix can last for years—especially on minor cracks. Just avoid using harsh cleaners or dropping heavy items in the tub. For deep structural cracks, the repair might be temporary. Keep an eye on the area and check for signs of new damage.

When to Call a Pro

There are times when calling a plumber or bathtub repair specialist is your best bet. Here’s when to consider it:

• The crack is large (over 6 inches)
• The tub moves or flexes under weight
• Water is leaking into the floor beneath
• You've tried a DIY fix before and the crack keeps returning

Final Thoughts: You Can Fix That Crack!

Don’t let a bathtub crack stress you out. With a little effort and the right materials, you can handle this project in a weekend. Not only will you save on the cost of replacement, but you’ll also get the satisfaction of fixing it yourself.

For an even more in-depth walkthrough, check out this detailed guide on How to Fix a Cracked Bathtub over at Cosy Home Idea.

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FAQs

Q: Can I use epoxy to fix a cracked bathtub?

A: Yes, epoxy resin is often included in fiberglass repair kits and works well for minor to moderate cracks.

Q: How long should I wait before using the tub after the repair?

A: Wait at least 24 hours to ensure everything has fully cured.

Q: Will the repair be visible?

A: If you take your time sanding and applying the topcoat, the patch can blend in almost seamlessly.