Sanded vs Unsanded Grout in Showers - A Comparison

Selecting the right type of grout for a shower installation is an important decision that can impact the look, longevity, and maintenance of the tile job. The key choice is often between sanded and unsanded grout, each with pros and cons to weigh for this wet environment.

Grout fills the joints between tiles and is a vital functional and aesthetic component of any tile installation. Using the right formulation and application method for shower tile grout ensures water-resistance, prevents staining and cracking, and creates a uniform finished appearance.

What is Grout and How is it Used in Showers?

Grout is a specially engineered mortar mix used to fill and seal the joints between tiles. It is applied after tiles have been set and provides adhesion to hold them in place while also creating a waterproof barrier.

In showers, grout provides these key benefits:

• Seals joints between tiles to block water penetration behind tiles
• Forms a water-resistant surface to prevent leaks
• Creates a uniform look by filling gaps and holes evenly
• Allows adjustment of tile spacing and alignment
• Provides stability and support for tile installations
• Resists mold, mildew and stains

However, grout also has some vulnerabilities in wet areas that require consideration:

• Absorption of moisture can cause discoloration or staining over time
• Cracks under stress or improper installation/curing
• Grout haze or film left on tile faces after application
• Potential for erosion or wear in joints, requiring repair

Sanded vs. Unsanded Grout: Key Differences

The two main categories of grout are differentiated by the inclusion of sand particles. Sanded grout contains finely graded sand for greater stability and strength. Unsanded grout has a smoother consistency without sand. Some other key differences include:

Composition

Sanded grout is a mixture of cement, fine aggregates (sand), color pigments and additives. The sand particles reinforce the grout and reduce shrinkage. Unsanded grout is composed of cement, color pigments and polymers without sand.

Texture

The sand in sanded grout creates a rougher texture and firmer feeling when dry. Unsanded grout has a smoother consistency and creamier texture before and after curing.

Appearance

Sanded grout has a coarser and less uniform look with varied sand exposure on the surface. Unsanded grout provides a more even, consistent color without sand grains visible.

Durability

The aggregate in sanded grout improves bonding and reduces shrinkage, making it more durable for wider grout lines and higher stress areas. Unsanded works better for narrow grout joints under 1/8 inch.

Water Resistance

Unsanded grout resists water penetration better overall. The polymers provide water-repellent properties while the smooth texture limits porous holes for moisture to penetrate.

Using Grout in Showers

When grouting shower tile, water-resistance is a primary requirement. The constant exposure to water requires maximum sealing and protection against leaks. Here are some factors to consider when selecting shower grout:

Joint Width

Narrow grout lines 1/16 to 1/8 inch are typical with small shower wall tiles. Unsanded grout is ideal for these thin joints. For larger tiles with wider gaps, sanded grout may be needed.

Tile Material

Natural stone and porous tiles require sanded grout for wider joints and better adhesion. Low-absorption glass, porcelain or ceramic may only need unsanded grout.

Exposure Level

Where water exposure is very high such as the walls and floor of a shower basin, unsanded grout provides maximum water repellency. Outside splash areas can use sanded.

Grout Line Appearance

For a smooth uniform look, unsanded grout suits small mosaic tiles and minimizes dark stripped lines. Sanded grout can highlight wider grout lines.

When to Use Sanded Grout in Showers

Though unsanded grout is the typical choice for shower walls, sanded grout may be preferred in some cases. Reasons to use sanded grout in a shower include:

• Grout joints exceed 1/8 inch in width
• Natural stone tiles with high porosity are being installed
• Floors or seat areas inside the shower with heavier demands
• Very large format tiles with wider grout lines
• Desire for greater durability and crack resistance

Larger Grout Lines

For wider grout joints, sanded grout provides greater fill capacity, adhesion, and strength. The sand particles allow it to be applied thicker.

Porosity Concerns

Materials like slate, travertine, limestone, and granite are more porous and prone to discoloration. Sanded grout resists moisture better.

Higher Stress Areas

Shower floors see more foot traffic and impact. Sanded grout stands up to wear better in these heavy use zones.

Applying Grout in Showers

Proper application technique is critical for shower grout durability. Here are some best practices to follow:

Joint Preparation

Remove all debris, dust and spacers from joints. Pre-seal porous tiles beforehand. Let tile mortar cure fully.

Mixing

Use the right proportions of powder to water in mixing grout. Allow proper slake time. Remix occasionally while applying.

Application

Force grout firmly into full joint depth. Hold float at a 45deg angle to avoid pulling out. Wipe diagonally across tiles.

Cleaning

Allow grout to firm up slightly before cleaning. Change rinse water frequently to limit haze. Buff with a soft cloth.

Curing

Keep area dry for 72 hours minimum. Air circulation speeds curing. Don't seal until fully cured.

Follow all manufacturer's directions for best results. Taking the time to properly grout shower tiles makes the difference between a lasting waterproof finish and leaks requiring expensive redo work.

In summary, here are some guidelines for choosing shower grout type:

• Unsanded for wall joints under 1/8 inch with ceramic, glass or porcelain tiles
• Sanded for floor joints, natural stone, larger joints, and high stress areas
• Match grout color to tile color for minimal contrast
• Use white grout for bright crisp finish with darker tiles
• Seal grout lines to prevent staining and increase water-resistance

Consider the look you want to achieve along with performance factors when deciding on sanded vs unsanded grout for your shower. Proper installation and sealing are key to durable, lasting results.