How Much Space Is Needed Between Tile And Tub?

When you’re installing a new tub, one of the crucial factors to keep in mind is the space between the wall tiles and the tub. This space is extremely important, and while it might not have immediate implications it could potentially ruin your installation if it’s not done right.

You’ll need at least ⅛ inch (0.32cm) of space between the tile and tub. This spacing leaves enough room for potential expansion and shifting as time passes. The distance is also small enough that the tub stays stable and fits snugly against the wall.

How Much Space Is Needed Between Tile And Tub?

Installing a new tub can be complicated, especially if it’s your first time. If you’re embarking on this project, read on to discover a few tips about the spacing you’ll need when installing a tub.

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Why You Need Space Between Your Tile and Tub

Understanding why you need space between the wall tiles and your tub is crucial for a successful installation.

You need this space for the seasons when your bathtub expands.

It may come as a shock if you’re unfamiliar with this phenomenon, but your bathtub expands every year when the temperature changes.

Without space for it to expand, the bathtub could damage the wall or its fittings, leaving you with a shaky installation.

While the amount of space you’ll need varies depending on the type of bathtub, in most cases you’ll need at least an eighth of an inch.

This much space gives enough room so the tub can expand without damaging its surroundings.

Match the Space to the Type Of Your Tub

You can exceed the ⅛ inch (0.32cm) of space if required, and some people opt for a quarter-inch (0.64cm) or even a half-inch (1.27cm) of space.

The amount of distance is up to your discretion, but if you want to be precise, you’ll need a few extra steps.

1. Decide the type of bathtub you’re going to be using. This is crucial because different materials will expand at different rates. For example, plastic tends to expand more quickly and significantly than a stone-resin bathtub.

2. Figure out the maximum temperature in your house during the year. You usually get to this point during the summer, but the actual top temperature will vary depending on where you live.

3. Use these numbers to decide the gap. Once you have the expansivity of your bathtub and the temperature of your home, you can use an expansivity calculator to figure out the maximum change to expect and account for it when installing your tub.

Fill in The Gaps

It might seem counterintuitive to leave a space for expansion only to fill it in later.

However, even while accounting for expansion, you have to make sure the space is filled properly with caulk or grout.

1. Caulk

Caulk is made from a variety of materials, but its most useful feature is that it’s flexible and waterproof.

This flexibility ensures that the bathtub material still has some leeway to expand when temperatures rise.

Another upside of using caulk is its waterproof characteristic, which is especially effective in the bathroom as it stays damp most of the time.

If you need help finding some high-quality caulk, you can try the Dap White Caulk (available on

It’s an affordable option that lasts long and will get the job done effectively.

2. Grout

Grout is also an option many people opt for as a cheaper alternative to caulking.

This material is typically sold as a dry powder that hardens once mixed with water and applied.

Unlike caulk, grout is a lot more rigid, so you want to ensure it’s paired with a material that doesn’t expand too much.

Apart from its lack of flexibility, grout is also not water-resistant like caulk, which is often made from materials and polymers that repel water.

As such, water usually penetrates through the grout, and these tiny leaks add up over time, wreaking havoc on your backer board if it’s not waterproof.

Luckily, there are specific types of grout that are waterproof, like epoxy grout, which can be applied instead.

However, keep in mind that while it may be waterproof, it’s still more rigid than caulk.

Related Article: Pros And Cons Of Sealing Grout

Final Thoughts

When you’re installing a new bathtub it’s essential to leave an expansion gap to ensure your bathtub doesn’t damage the tiles as the temperature rises.

Generally, you’ll want at least 0.125 inches (0.32cm) of space, but you can widen this gap based on the materials used and if you’re able to seal it properly.

It’s also vital to use the best sealant to protect your walls and bathtub.

While both caulk and grout are dependable and have their uses, you’re better off utilizing the flexibility of caulk to fill the space between your tiles and tub.

Cheers, tools owners!

Hi there! My name is Jack and I write for ToolsOwner. I have a passion for everything related to tools and DIY projects around the house. You often find me in my workshop working on new projects.