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How To Repair A Hole Or Crack In A Shower Base [9 Steps!]

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Though it might be tempting to look over minor imperfections, repairing small cracks or holes in a shower base can prevent larger issues from occurring down the line. Tackling these issues doesn't have to be difficult or costly. In fact, repairing the damage could save you the money you'd spend replacing the whole base. So how do you repair a hole or crack in a shower base? We've done the research and have some steps for you.

To repair a fiberglass shower base, take the following steps:

  1. Thoroughly clean the shower base.
  2. Assess the damage and plan the repair.
  3. Address support issues before making any repair.
  4. Sand and prep the area.
  5. Mix the filler material.
  6. Apply a patch if using one.
  7. Repair the crack or hole with the filler.
  8. Sand again after the filler sets.
  9. Refinish the surface.

Now that we've addressed the basic steps to repair cracks or holes in the shower base, let's discuss each one in more detail. We'll list some tools you'll need, as well as go over some additional questions you might have. Keep reading.

Beautiful bathroom with shower and window, How To Repair A Hole Or Crack In A Shower Base [9 Steps!]

How To Repair A Hole Or Crack In A Shower Base

The types of materials and tools needed can vary depending on how extensive a repair you need. We'll list everything you could potentially need. The stability of your shower floor will determine if the extra tools are needed. If the shower floor seems squishy or has a lot of give you'll need more tools to repair the problem.

For small crack/hole repair:

  • Tub/tile cleaner
  • Protective gear (disposable gloves and mask)
  • Sandpaper (80 and 220 grit)
  • Masking tape
  • Polyester resin or epoxy in putty form
  • Liquid hardener
  • Mixing stick and tray
  • Fiberglass mesh or cloth (if desired)
  • Putty knife
  • Solvent cloth

Many of the above-mentioned tools come in bathtub and shower repair kits so you don't have to purchase full-sized products for a few cracks. Most of these kits come with the resin or epoxy mix, hardener, mixing sticks, and sometimes color matching hues to assist at hiding the patch.

View this repair kit on Amazon.

In addition to the materials listed above, if you need to add support underneath the shower floor, you'll need:

  • Drill
  • Low expansion spray foam

1. Thoroughly clean the shower base

To begin your repair, you'll need to thoroughly clean the shower floor using a standard tub and shower cleaner. The area needs to be free of any soap scum and oils to have a successful repair. Allow the area to dry fully before proceeding.

View this cleaner on Amazon.

Read our post, "12 Types of Shower Bases and Pans," to find out more about shower bases.

2. Assess the damage and plan the repair

Once the shower base is thoroughly clean, it's time to assess the damage. If you only have a few cracks or small chips, you can likely just use the resin or epoxy mixture to fill in the damage. If the cracked area seems to be lacking support, you'll need to address that issue before covering the cracks with a fiberglass patch and then resin. Often, the heart of the issue is a lack of support, so don't skip repairing it if necessary.

3. Address support issues before making any repair

If the floor of the shower base needs additional support, you'll need to add that support by using low-expansion foam. To get the foam under the shower floor, you'll need to drill six to eight holes (more or less depending on how much support is needed) in the shower floor a few inches outside of the cracks. Wearing gloves, inject the foam into the holes.

You'll know you've injected enough when the foam expands out of the holes and likely the cracks you're repairing as well. Wipe away excess with a solvent cloth. Allow the foam to dry according to the manufacturer's instructions. After drying, you can use a utility or putty knife to scrape away any remaining excess. 

View this spray foam on Amazon.

4. Sand and prep the area

Use 80-grit sandpaper to lightly sand just around the cracks, holes, or chips. If you've had to use foam to support the floor, you can sand away any excess and create a level area to work. This gives the area grit so the epoxy or resin will adhere. Before standing, section off the areas around the cracks with masking tape to avoid sanding areas you don't intend to repair.

View this sandpaper on Amazon.

5. Mix the filler material

Wearing protective gloves in a well-ventilated area, mix the epoxy or resin putty with the hardener using your mixing stick. Set the tray on top of some scrap cardboard while mixing to prevent any excess mix from spilling on floors or other surfaces. If you're trying to color match, mix in color at this stage as well. 

View this epoxy and hardener on Amazon.

6. Apply a patch if using one

For a smoother repair, you might consider covering the cracks with a fiberglass mesh or cloth before applying the putty. If using, cover the cracks with the mesh or cloth and cut to size. The cloth should expand a few inches outside of the crack or hole. Using this patch can keep the area from dimpling after repair. 

View this fiber mesh on Amazon.

7. Repair the crack or hole with the filler

Apply the putty over the cracks or holes and smooth it down using the putty knife. If using a patch, it might be necessary to apply a bit of the putty underneath it to hold it in place before applying the putty over it. Don't worry about piling on too much, as you'll be sanding it later. Take your time filling in the cracks or holes and smoothing them. 

View these putty knives on Amazon.

8. Sand again after the filler has set

Allow the putty to dry according to the manufacturer's instructions. Using the 220 grit sandpaper, sand the area until smooth using careful, even pressure. This will take some time to get the area smooth and of a similar texture to the rest of the tub. 

View this sandpaper on Amazon.

9. Refinish the surface

If desired, use a finisher to get an even color on the shower base. Many kits come with a finisher, but it's readily available in an easy spray form. 

View this finisher on Amazon.

Read our post, "6 Simple Steps to Clean an Acrylic Shower Base."

What causes a shower base to crack?

The main issue that can cause cracks in the shower base is poor installation. If proper support isn't added to the shower base under the shower pan, the pressure from people standing in the shower over multiple showers causes it to crack. Many installers rely on support from the corners and the drain, which doesn't allow for extensive use. Outside of an installation issue, if the shower base is old, the structural integrity could be compromised.

How do I know if my shower is fiberglass or acrylic?

The easiest way to tell the difference between fiberglass and acrylic is to look at the coloration. Over time, fiberglass can have uneven colors and fade in spots. Additionally, acrylic is warm to the touch. If you touch the shower base and it feels cool even in a heated room, it is likely fiberglass.

How do you fix an acrylic shower base?

Use the process outlined above for acrylic shower bases as well. However, you must be more careful if you drill holes in acrylic as it can sometimes crack more. Acrylic isn't quite as strong as fiberglass in this regard.

Can a shower base be replaced?

The shower base can be replaced if necessary, though repairs are oftentimes easier and less expensive. It's advised to acquire a contractor to replace a shower base if you've decided you need a whole new one. 

In Closing

With a few tools and materials, you can repair cracks or small holes in your shower base with a weekend. Just gather the tools and remember your safety equipment, and you'll have the shower base as good as new before you know it.