Grout Lines Cracking? The Secret to Choosing the Right Grout for Your Shower

Is your beautiful new ceramic tile shower starting to look a little worse for wear? Are you noticing cracks, pits, and crumbling in the grout lines, no matter how much you scrub? Few things can ruin the look of a shower faster than failing grout. And even worse, cracked grout opens the door to moisture damage and mold growth in your wall interior.

Choosing the optimal grout for your specific shower installation is the key to preventing cracks and enjoying an enduring waterproof finish. We’ll also provide tips for selecting the right type based on your tile size, walls versus floors, foot traffic, and other factors unique to your shower.

Sanded vs. Unsanded Grout – What’s the Difference?

Sanded and unsanded are the two main categories of grout for shower tile. What sets them apart? It comes down to one key ingredient:

Sanded Grout

As the name implies, sanded grout contains fine sand in its mixture. The sand aggregate gives it an extremely durable, resilient texture. It provides excellent adhesion for wider grout lines and high-traffic floors.

Sanded grout has some key advantages:

sanded vs unsanded grout for shower
  • The sand provides enhanced structural strength to resist cracking from movement or pressure.
  • It is recommended for grout lines wider than 1/8 inch.
  • Sanded grout stands up to heavier use, foot traffic, and moisture over a long period.

The only real downside is the gritty, coarser finish of sanded grout. It can also be more challenging to work into very thin grout lines between tiles.

Unsanded Grout

Unsanded grout has a smooth, fine finish because it does not include sand aggregate. The primary components are cement and polymers like latex or acrylic.

Here are the defining characteristics of unsanded grout:

  • Preferred for thin, narrow grout lines 1/8 inch or less.
  • Easier to spread and work on vertical shower walls.
  • Provides a uniform appearance without sandy texture.
  • Less durable for high-moisture and foot traffic.

For very thin grout joints and application on vertical surfaces like shower walls, unsanded grout is often the better fit. However, it lacks the long-lasting stability and resilience of sanded mixes.

Factors That Determine Best Grout for Your Shower

Now that you know the core differences between sanded and unsanded grout, how do you choose the right type for your specific shower installation? Consider these key factors:

Tile Size and Grout Line Width

One of the most important considerations is the spacing between your tiles, known as grout joint width. Are your grout lines less than 1/8 inch or wider?

For very narrow grout joints, you’ll want to go with unsanded grout. Its finer texture can fully penetrate the thin spaces. Sanded grout is too thick and coarse; it won’t properly adhere in gaps less than 1/8 inch.

For grout lines 1/8 inch and above, sanded grout is the optimal choice. At this width and beyond, the improved durability and water resistance of sanded grout make it ideal. The sand allows it to bind strongly and resist cracking or washing out, even with wider spacing between tiles.

Using the wrong grout for your grout line width can be disastrous. Thin unsanded grout in wide joints is prone to cracking under pressure. Meanwhile, coarse sanded grout simply won’t fit into thin crevices, leading to weak adhesion and future failure.

Take measurements to confirm your grout lines before finalizing grout selection. Also factor in your tile size – larger tiles generally require wider grout lines, again calling for sanded grout’s benefits.

Walls versus Floors

In addition to grout line width, the orientation of your tiles impacts the ideal grout choice.

For shower floors, sanded grout is strongly advised. The high-traffic pressure of feet over time calls for maximum durability. Exposed to dripping water, shampoos, and steady use, shower floors also benefit from sanded grout’s water resistance.

On shower walls, either sanded or unsanded grout may work well depending on other factors. The smoothness of unsanded grout provides a unified appearance on walls. With less direct pressure and moisture exposure, shower walls can sometimes get by with less durable unsanded mixes.

However, sanded grout is still a smart choice for walls in many cases. Water flows over vertical shower surfaces as well, so the waterproofing perks of sanded grout come in handy. Its strength also helps walls stand up to bumps, scraping, and routine spray over time without cracking or eroding.

Type of Tile Material

Natural stone, ceramic, porcelain, and glass tiles all have distinct characteristics that factor into grout suitability.

For natural stone like marble or travertine, unsanded grout is often preferred. The smooth finish matches the refined look of polished stone. Sanded grout can also scratch some delicate stone surfaces. However, make sure any unsanded grout for stone is high-quality and contains polymers to prevent discoloration.

Porcelain and ceramic tiles pair well with either grout type. The tile material itself is dense and durable enough to hold up with the thinness of unsanded mixes. But sanded grout provides unbeatable strength for high-traffic porcelain and ceramic floors.

Mosaic sheets made of small glass tiles fit best with unsanded grout. The thin grout lines and intricate tile patterns require smooth grout that can fully penetrate narrow spaces.

Think about your specific tile material and its inherent durability when choosing shower grout. Combine this factor with expected traffic, moisture levels, and grout joint width for the ideal match.

Amount of Foot Traffic

We’ve emphasized a few times already that sanded grout stands up to heavy foot traffic better than unsanded. But why is that exactly?

The sand aggregate in sanded grout forms an incredibly strong bond as it cures. This allows the grout to withstand constant pressure without cracking or crumbling. Showers see a lot of barefoot traffic over their lifetime, so durable grout is essential.

Without sand for reinforcement, smooth unsanded grout relies solely on cement and polymers to maintain its stability. Over years of direct force, thin unsanded grout is likely to crack or pit in areas like the shower floor.

For any shower that will see regular use by multiple household members, choose reinforced sanded grout for maximum resistance to heavy feet over time.

Proper Grout Installation and Sealing

While grout selection lays the foundation, proper installation and sealing are also key to lasting, crack-free results.

Once your grout type is chosen, follow these tips for successful installation:

  • Allow tile mortar to fully cure before grouting, generally around 24 hours.
  • Apply grout sealer to tiles beforehand as a shield against staining.
  • Prep the grout joints by clearing out debris and wetting slightly.
  • Use a rubber grout float to spread grout forcefully into joints, removing excess.
  • After curing, buff any remaining grout film with a soft cloth for smooth finish.

Sealing is a must for both sanded and unsanded grout. Sealer forms a protective barrier, preventing stains from grease, dirt, and grime. It also reduces moisture absorption, which can erode grout over time.

Apply a penetrating grout sealer to finished installations. Re-seal at least once a year thereafter, and more often for frequent showers. Proper sealing locks in the integrity and beauty of your grout.

Signs Your Shower Grout is Failing

With aging and excessive moisture, even quality grout eventually requires replacement. Watch for these signs of grout failure in your shower:

  • Cracks – Jagged lines, pitting, or missing chunks of grout
  • Discoloration – Grout changing to a darker shade, especially along joints
  • Staining – Noticeable grease, soap, or hard water marks
  • Powdery Texture – Grout feels chalky when touched instead of solid
  • Water Leaks – Damp areas or water dripping through grout

At the first signs of grout deterioration, try deep cleaning and re-sealing the affected areas. If issues persist, your safest bet is to call in a professional regrouting service.

DIY Regrouting vs. Calling a Pro

Can you tackle failing grout yourself or is it time to phone an expert? Consider DIY shower regrouting if:

  • Damage is limited to a small area of grout lines.
  • The underlying issue causing failure has been resolved.
  • Tiles are still fully attached and secure.

Call in a professional grout removal and replacement service if:

  • Damage is widespread on walls or floors.
  • Grout failure may indicate larger moisture issues.
  • Replacing all grout down to tile edges is needed.

One advantage of professionals is their ability to fully cut out and replace all grout, ensuring a consistent finish. Grout regrouting costs $1 to $3 per square foot on average.

For DIY work, carefully chisel out all old grout at least 1/8″ deep using a special grout saw. After cleaning joints, simply regrout the open spaces with your new grout.

Choosing suitable grout establishes your shower for beauty and performance right from the start. Sanded grout is tough to beat for its durability in most applications. But unsanded shines for specific tiles, walls, and narrow grout lines where a smooth finish is desired.

Understand your unique tile parameters, then match them to the ideal grout blend. With proper installation and sealing, you’re guaranteed a shower that will look freshly grouted for years.

We hope these tips give you confidence that selecting the perfect grout for your shower doesn’t have to be complicated. Simply make an informed decision based on tile specs and traffic levels using our guidance. With your tiles locked in place by durable, waterproof grout, you can enjoy a shower space that stands up to daily use without losing its sleek finish.

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