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Will Flex Seal Fix A Cracked Bathtub?

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Flex Seal is a unique substance that comes in handy for fixing leaks. It comes in a paste or liquid form and turns into a solid, flexible, rubber-like material when dry. There are several products under the flex seal line – flex seal liquid, flex paste, flex glue, and flex tape, to name a few. So, will flex seal fix a cracked bathtub? In short, yes (mostly). If the damaged bathtub has a small crack that water leaks through, flex paste will help plug it. But, in the case of a larger crack, flex seal might only be a temporary fix. Read on to find out more.

Fixing a porcelain bathtub

Fixing a porcelain bathtub

Small cracks in porcelain bathtubs can be fixed using flex seal products. Flex seal paste is a smart choice for thin cracks. It spreads into the tiniest crevices and seals it airtight. It is essential to read all instructions on the package before using the flex seal. A crack in a porcelain bathtub can be sealed using the following steps – 

Also, Read – Best Shower Curtain for Clawfoot Tub (Extra Wide)

Step 1

Using a dry towel, wipe down the surface of the bathtub such that it’s dry to touch. 

Flex seal products work well on wet or dry surfaces. But, clean and dry surfaces yield the best results.

Step 2

Apply an even layer over the crack using sufficient pressure using a putty knife. Smooth out the edges, so the paste looks nice and even, and leave it to dry.

Flex seal paste is dry to touch in under thirty minutes. But, leaving it untouched for 24-48 hours for complete adhesion is recommended. 

How do I fix a crack in a plastic bathtub?

cracked bathtub

A crack in a plastic tub might be filled using a flex seal. However, flex seals may not stick well on some plastic surfaces. Thus, testing the product out on a small spot before usage is wise. If the flex seal adheres well, the steps above are helpful to fix plastic bathtubs. 

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Flex tape can also be used as an alternative for fixing small cracks in plastic bathtubs.

How to prevent bathtub cracks?

The easiest way for a bathtub to crack is when heavy items repeatedly fall into it. For example, an improperly fixed shower curtain rod could keep falling in. Likewise, heavy bottles of shampoos or body wash placed around the edge can cause dents when falling. Slipping and falling into a bathtub is dangerous and ends with a cracked tub in most cases.

How to prevent bathtub cracks


Use rubber mats at the base of your tub to provide a better grip. Rubber mats not only prevent slips and falls but can also add a layer of protection. A mat can provide slight cushioning to your tub from objects that might fall into it. Learn more about picking the right rubber mats

You can easily prevent such accidental cracks. First, make sure the screws are tight and hold the curtain rod in place. Read more here to find out how to fix a suction-based rod that keeps falling off properly.

Move bottles of toiletries out of the way by installing shower caddies or shelves over the bathtub and fixing it tightly.

Can a crack in a bathtub be repaired by DIY?

A small crack in a bathtub can be repaired by DIY. A flex seal can work to seal the tub and prevent leaks for a short-term fix. And as a more permanent solution, epoxy can be used to fill in the crack. However, it is best to call in a professional for bigger cracks and get the tub repaired.

Wrapping Up

Hairline cracks in porcelain tubs can be fixed using flex seals. However, this should not be used as a permanent solution. Flex seals can plugin leaks but might not be able to withstand the water pressure of a filled bathtub. This might cause the crack to widen, worsening the problem in the long run.

Also, Read – How to fix a crack in a fiberglass tub?

Cracks in fiberglass tubs are usually fixed with epoxy. Once the epoxy is dry, it is sanded down to achieve a smooth finish. However, the best fix for bigger cracks in bathtubs is to call in a professional. This can help prevent injuries and further damage to the bathtub.