Can you repair a bathtub crack?
Your bathtub is likely one of the most frequently used items in your bathroom. Whether you prefer a morning shower or like to take a luxurious soak at day’s end, you probably use your tub daily. The extensive use your tub gets makes it more susceptible to normal wear and tear than lesser-used items in your home.
Over time, you may notice chips or cracks forming in the tub. The rough and uneven surface can be uncomfortable to the touch and further pose a safety hazard, potentially causing scrapes. Additionally, a chip or crack will worsen with time, resulting in more significant damage — and potential leaks — if not fixed. Don’t panic: There’s no need to throw out your bathtub and replace it entirely. You can extend its lifespan with some DIYer know-how.
This home improvement guide explains what causes those pesky cracks and chips and provides a step-by-step guide on how you can fix them.
What causes a crack in a tub?
In the past, bathtubs were often made of stainless steel or porcelain-coated cast iron. Today, the majority of bathtubs are made out of synthetic materials like fiberglass or acrylic. While these modern materials are durable and affordable, they may become brittle and develop fissures, small cracks or pits over time.
Certain external elements increase the likelihood of damage. An improperly installed tub is one common cause. A heavy bathtub needs sufficient support from below to ensure equal weight distribution. Otherwise, the tub’s weight combined with the weight of a person inside it will be distributed unevenly, causing excessive pressure at select points. This can result in hairline fissures, which worsen into larger cracks over time.
Another common cause of bathtub damage is the force of heavy objects falling. If you’ve ever dropped a full bottle of shampoo or conditioner in the shower, you know how much power these objects can exert (and what a big noise they can make in the process)! The force of a heavy object falling into the tub can likewise cause barely perceptible dents and divots, which may worsen into deeper pits later.
Finally, household cleaners are another reason for bathtub damage. Abrasive cleaners like bleach can slowly eat away at the tub surface’s glossy finish, eroding the material and making it more susceptible to damage. A damaged finish can also expose the underlying fiberglass or acrylic materials to water, causing them to weaken and eventually crack and break.
Bathtub damage is often the result of a combination of these factors. For example, let’s say a tub is improperly installed with uneven weight distribution. It will be more susceptible to damage to begin with. Then, a falling shampoo bottle may cause a small chip. This small chip may then grow after being subjected to abrasive chemical cleaning.
How to repair a bathtub crack: A 6-step guide
The sooner you repair a chipped or cracked bathtub, the better. The damage is only going to get worse if you don’t fix it. Follow the below steps to get the job done. Note that this guide applies specifically to modern fiberglass tubs, the predominant model, although the details can be adapted to other materials.
Here are the tools needed for a fiberglass bathtub repair kit:
- Protective gear (goggles, respirator or mask and gloves)
- Cleaning supplies (household cleaner, sponge, cotton balls, acetone or rubbing alcohol)
- Small drill
- Two-component foam
- 80-grit sandpaper
- Rotary tool
- Fiberglass mesh
- Fine grit sandpaper
- Fiberglass repair kit (there are also repair kits for acrylic or porcelain tubs — make sure to get the right one for your needs). These kits generally include the following:
- Resin, epoxy putty, paste
- Liquid hardener
- Mixing tray and stick-like mix applicator
- Finishing polish
- May also have colorant for non-white tubs
Step 1: Assess the damage
The repairs will vary depending on the type of damage. First, identify whether you are dealing with a crack, chip or hole. Chips and holes will be repaired differently than a crack. We’ll explain the details and address the differences as we go through each step.
Step 2: Prep the area
Use a non-abrasive household cleaner and a soft sponge to clean the area. If there is soap scum, glass fiber or oil buildup, you can use a cotton ball soaked in acetone or rubbing alcohol to remove it. Cleaning the area thoroughly will give you a clear, unobstructed view as you work.
Step 3: Drill holes and add foam
If your bathtub lacks support, resulting in uneven weight distribution, it’s important to tackle this underlying issue. Removing the entire tub and putting support infrastructure in place is costly and time-consuming. This step offers an alternative solution.
The areas around a chip or crack are likely those in need of added support. Target these weak spots, drilling six to eight small holes around them. Then, take your two-component foam and inject it into the holes you’ve drilled. The foam will take a few minutes to harden. Once it’s set, it will provide a strong foundation for the previously unsupported parts of your tub.
Step 4: Apply the proper bathtub repair kit
With the underlying support taken care of, you can now address the superficial issue: the unevenness caused by the crack, chip, pit or dent. As mentioned in step one, cracks are treated differently from chips or holes. First, prep the area to be fixed as follows:
- For a crack: Gently grind or sand the crack to widen it slightly. Using 80-grit sandpaper with a rotary tool, grind a bevel that’s approximately 1.5 inches wide, with the crack at the center.
- For a chip or hole: Take the fiberglass (or appropriate material) mesh patching and lay it over the hole or crack. Trim it so that it’s slightly larger than the opening it’s covering. For deep holes, you may need multiple layers of mesh.
Next, apply the bathtub repair kit. Again, make sure the repair kit is made for your bathtub’s specific material, whether that’s porcelain, enamel, ceramic, acrylic or fiberglass bathtubs. Here’s a quick breakdown of how to apply the repair kit (although you should always go by the kit’s specific instructions):
- Wearing your protective gear, mix the kit’s resin/epoxy putty/paste and liquid hardener.
- Use the mixing stick and tray provided with the kit to spread the mixture into the crack or on top of the fiberglass mesh. A deeper hole may require you to spread the mixture inside the hole.
- Work the mixture thoroughly into the fissure or pit, getting it into all crevices. This is important to preventing dimpling. It’s OK if the mixture spills over a bit — you’ll sand it down later.
Note that if you are working with a non-white tub, you should ensure you get a mixing kit with color match additive. You must then generally mix this colorant in with the resin/epoxy putty/paste and hardener at the beginning. Alternatively, you can paint over the repaired spot later so it blends in (see step six).
Step 5: Sand the dried filler
Give the mixture two to three hours to set. Larger holes with more filler will require more time. Once it’s set (hard), use the fine grit sandpaper to eliminate unevenness on the surface and create a smooth finish. Don’t be afraid to apply pressure when sanding.
Step 6: Paint and buff to desired finish
Finally, take the finishing polish (provided with the repair kit) and use it to blend in the repaired area with the surrounding tub surface. If the color of the repaired area doesn’t match the rest of the tub, you can paint it. Buff and shine for your final bathtub refinishing, and you’re good to go!
How much does it cost to fix a bathtub crack?
According to HomeAdvisor, the average cost to fix a fiberglass tub can run from $20 to $240. The exact price will depend largely on whether you do the job yourself or hire a professional: A DIY $20 repair can become a $200 repair if you hire someone else to take care of it. Of course, there are other factors to consider, like the extent of damage that needs to be addressed.
When you factor in drying time, a bathtub repair project can take as long as four to six hours. You may still opt to hire a professional if you don’t feel like dealing with this, despite the added cost. An expert will have the tools needed to handle the fix, so you won’t have to worry about finding and buying repair supplies.
Avoid costly bathroom repairs with a home warranty from Cinch Home Services
A home warranty can cover critical bathroom repairs due to normal wear and tear, ensuring a prompt and professional fix — and sparing you the stress of DIY jobs. Cinch Home Services offers home warranties to cover essential bathroom systems, like your water heater and plumbing. This protection allows you to rest easy knowing that you have the coverage you need to ensure your bathroom is always up and running. Find out more about our home protection plans.