Why Did My Shower Pan Or Base Crack? [And How To Fix It]

Shower pans are a useful alternative for traditional bathtubs, but they are available in various materials. So, you may be wondering why your shower pan or base has cracked. Although the shower base underneath the pan is generally durable for years, it can still be vulnerable. We have thoroughly researched why your shower pan or shower base may have cracked and how to fix the problem.

Shower bases and pans typically crack due to instability caused by age and wear, water damage, or improper installation. You can repair a concrete base by using a flexible sealant. However, it might need replacement, depending on the crack's severity and the underlying cause. Repair a shower pan based on its material, using either a fiberglass repair kit (fiberglass or acrylic) or epoxy (ceramic or stone). 

It is important to identify the difference between a shower base and a shower pan. And because shower pans are built differently, there are many different issues and solutions. Keep reading to learn how to fix a cracked shower base or pan, how long they should last, and what to do if you need to replace a shower pan.

A minimalist modern bathroom with large tiles, Why Did My Shower Pan Or Base Crack? [And How To Fix It]

Can you fix a cracked shower base?

A shower base is often mistaken for the shower pan because the two labels are often used interchangeably. But it is crucial to note that they are not the same part of your shower floor. A shower base is usually a combination of mortar and cement that sits underneath the shower pan that you actually stand on.

This base provides stability for the shower pan on top. As such, a cracked shower base is a larger problem because when it falters, the shower pan can also be affected. And although it’s possible to repair a cracked shower base, the process can be much more challenging than patching a shower pan.

Glass shower and white bathtub in clean bathroom interior with mosaic tile trim


Why did my shower base crack?

While cement is considered to be highly durable, it can still be subjected to stress that breaks it down. For example, a new house settling can crack a shower base. Older homes' general wear and tear can also damage an aged shower base.

A shower base can also be worn down by water damage. Leaks sometimes find their way to the shower base through grout or cracks. Cement is actually a porous material, so any standing water remaining from an unfound leak will erode its durability over time. 

The most likely reason for your shower base to crack is poor installation. Improperly mixed cement can easily become unstable over time.

How to fix a cracked shower base?

If the shower base is cracked, then you will always have to remove the shower pan. The work area should then be prepared by protecting the drain and showerhead. Next, tape off nearby areas so that you can clean and repair the base.

Smaller cracks in a cement shower base might be repaired by using a flexible sealant, which should be specifically designed for your material. However, it may be necessary to patch the shower base using more cement. 

This would require you to mix cement in a bucket, then use a trowel to spread it out over the affected areas. You’d need a construction level to make sure the base is still even as the final result. 

In worse cases, you might have to reinstall the shower base altogether. It may become necessary to break the base into smaller pieces so that it is easier to handle and remove.

You'll need the skills, tools, and appropriate materials to prepare the underlay for a new installation. It might be best to hire a professional for this versus a DIY job to ensure lasting results.

Can you patch a shower pan?

Bathroom with basin, shower cabin, large mirror and chrome silver heater at gray wall

The shower pan you stand on can be made of various materials, such as acrylic. But most of the time, your shower pan will be made of either fiberglass or tile. 

It is possible to patch these shower pans, but there are completely different solutions for cracked tiles or cracked fiberglass. That’s because fiberglass is a collection of interwoven glass fibers. But tile shower pans are often made of ceramic or stone.

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

Both acrylic and fiberglass shower pans are more flexible and lightweight than the alternatives. However, fiberglass is popular because it is relatively inexpensive. Acrylic is typically more costly.

Also, acrylic is found to be more durable than fiberglass. This is because the acrylic sheets are thermoplastics reinforced with fiberglass. Fiberglass shower pans do not have an acrylic addition. They are simply sprayed into a mold and blanketed with a layer of resin. 

As such, acrylic materials may give less against your weight and have a thicker design than fiberglass. Also, because fiberglass is so unusually lightweight and thin, any upstairs bathrooms are more likely to use this material.

How to fix fiberglass shower pans

Firstly, you will need to cover the showerhead and protect the drain so that you can thoroughly clean the area. Then, you will need to drill a hole on each side of the cracks to prevent them from growing while you work. Carefully drill holes several inches apart, surrounding the damaged sections. 

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These openings will allow you to inject spray foam underneath the shower pan, which will restore the stability of the cracks. Fill each hole until the spray foam begins to rise out. Remove any excess foam.

Now, you need to use sandpaper to level out the crack and holes into an even surface. This way, the surface will successfully bond with epoxy or body filler. 

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For larger cracks, you should now add a fiberglass mesh patch. You can use a commercially sold fiberglass repair kit to have all the necessary materials on hand. After the fiberglass patch hardens, it can be sanded and cleaned. To finish, apply epoxy or body filler, sand that layer down too, and clean the area again.

How to fix tile shower pans

For tile shower pans, the stability of your tiles also depends on the grout in between them. It may be necessary to remove the old grout and replace it with new grout. Do not simply add a new layer of grout, which would simply be subject to the weakness of the existing grout.

When tiles only have minor cracks, you can simply apply tile cleaner and then fill in the damage with clear epoxy. Then, you should level the epoxy and remove any excess. After the clear epoxy cures, you can paint it to match your tile.

However, tiles with major cracks will need to be replaced. You will have to remove the surrounding grout and break the tile into pieces with a hammer. Then, a chisel should allow you to carefully remove the old tile. The area needs to be cleaned before adding a new one.

How long does a shower base last?

A true shower base, being made of durable cement and mortar, should last around 15 to 20 years. You can read the post "How Long Should A Shower Base Last?" for further details.

The lifespan of your shower pan can vary based on the material it is made from. For example, acrylic and fiberglass shower pans are similar, and will both tend to last around 10 years under conventional circumstances. However, outside factors such as a new house settling can lower the shower pan’s stamina.

Tiles that are used in a shower can survive twice as long with proper care, around 20 years. Cultured marble has also been known to last about 20 years. That’s because it is highly durable and not a porous material, which makes it unusually waterproof.

Do plumbers replace shower pans?

Yes, some plumbers are known to replace shower pans. For example, businesses such as Dunedin Plumbing in Florida offer shower pan replacement.

However, this isn’t always the case. A local handyman service, tile setter, or bathroom specialist may be necessary.

How much does it cost to replace a shower pan?

Modern bathroom with shower

Hiring a professional to replace your shower pan will have various costs and require unique quotes based on where you live. Replacing it yourself will involve the cost of the shower pan and the necessary tools.

The total cost will depend mostly on the pan, which ranges from $100 to $500 dollars. You can read the post "How To Install A Shower Base On Concrete Floor" for tips on doing the job yourself.


The shower base is easily overlooked compared to the shower pan, but both layers are often vulnerable to excessive stress. Whether age or installation has compromised these parts of your shower, it is important to fix them or replace them correctly. Otherwise, any existing damage will only regrow over time. It is now clear how to distinguish a shower pan and shower base, as well as how to fix their cracks.

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