You should use both, but in different areas. Grout is for the flat surfaces between individual tiles, while 100% silicone sealant is mandatory for changes of plane (corners and edges) where walls shift and flex.
In a shower, use grout for flat, tile-to-tile joints and silicone for corners, seams, and areas that change planes. Grout locks the tiles in place, while silicone provides a flexible, waterproof seal that accommodates the natural expansion and contraction of your home.
Builders often skip sealing grout to cut costs, save time, and avoid returning to the job site. Additionally, many modern polymer-modified grouts are stain-resistant, and sealing un-cured grout can trap moisture. Some installers even use it as an upsell or exclude it because sealing can leave a hazy film on certain tiles.
The best grout for Saltillo (terracotta) tile is a heavy-duty, sanded Portland cement grout formulated explicitly for wide joints (typically 1/2 to 114 inches). Standard thin grouts will shrink and crack in these large gaps. Top industry choices include MAPEI 2-1/2 to 1 Saltillo Tile Grout and Custom Building Products Saltillo Grout Mix.
Silicone sealants reign supreme as the go-to choice for shower applications. Renowned for their exceptional flexibility, water resistance, and durability, they offer an unrivalled sealing solution.
The best waterproof sealant for showers is generally considered to be 100% silicone, with GE Advanced Silicone 2 Kitchen & Bath Sealant frequently ranked as a top choice for its 30-minute water-ready formula, 10-year mold-free protection, and high flexibility. Other top contenders include GE Supreme Silicone for high adhesion and Gorilla 100% Silicone Sealant for durability.
The shower enclosures have to be sealed with silicone only on the outside. If silicone is applied inside, the water possibly leaking through the profiles may reach the outside, whereas if both the inside and outside have been sealed, water might stagnate inside the profiles themselves.
Grouting mistakes make your tile project look less than perfect—despite all of your hard work. Common errors include adding too much water to the grout mix, holding the grout tools wrong, and neglecting timing.
Rustico's TerraNano Sealer is a one of the best sealers for Mexican Saltillo Floor tiles. One gallon covers up to 400 sq / gallon and can last 10-15 years depending on foot traffic and general wear of the flooring.
Made from epoxy resins and a filler powder, epoxy grout forms a highly durable bond that withstands moisture, stains, and chemicals. Advantages of Epoxy Grout: Waterproof: Perfect for areas constantly exposed to water, like showers. Stain-Resistant: Resists discoloration from mold, mildew, and cleaning agents.
For standard cement-based grout, you should wait at least 48 to 72 hours before applying a sealer. This allows the grout to cure completely so that trapped moisture can evaporate.
Technically, you can regrout over old grout, but it is not recommended to just smear new grout on top. Doing so will likely result in a weak bond, leading to cracking, peeling, and an uneven finish.
If you don't seal standard cement-based grout, it acts like a sponge. The porous material absorbs water, soap scum, and everyday spills, which leads to permanent discoloration, foul odors, and accelerated degradation. Over time, trapped moisture can spawn mold and mildew beneath the surface, potentially loosening the tiles.
Use silicon for your perimeter seals, vertical wall joints and on the outside of your shower screen. Also silicon where tile goes to wooden trims, around vanity etc. Grout for everything else where it's just tile to tile on flat surfaces.
Most silicone isn't paintable, so you wouldn't want to use it in areas that would get painted at any point. If you're looking at exterior products, polyurethane caulk is a good option as well. Most caulks will do that if not painted.
Epoxy grouts are the best option for a shower – they are the most water- and stain-resistant of all grouts.
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You should reseal your Saltillo tile every 1 to 5 years, depending on foot traffic, location, and the type of sealer. Because Saltillo is highly porous terracotta, routine maintenance of its protective barrier is essential.
Professionals use heavy-duty, commercial-grade acidic and alkaline cleaners, often paired with high-pressure rotary hot-water extraction machines. For stubborn stains, they frequently rely on professional-strength stain removers, or a simple DIY mix of baking soda and hydrogen peroxide.
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Bleach can also weaken grout and damage any sealer that's been applied. Over time, bleach makes grout more porous, which means it gets dirty even faster. Why to avoid: Like bleach, ammonia strips away protective sealers. It can also discolor grout and weaken the integrity of the grout over time.
Let the grout set for 15 to 30 minutes and then begin gently wiping off the excess grout with a clean, damp sponge. Rinse the sponge frequently, using one bucket for getting the excess grout off the sponge and the other for re-dampening the sponge.
Hotels keep glass shower doors spotless by combining strong commercial cleaning agents with routine maintenance and smart preventative coatings. Because they deal with heavy daily guest turnover, housekeeping staff rely on quick but highly effective strategies to prevent soap scum and hard water buildup.
Loctite Perfect Finish Kitchen & Bath Sealant creates fantastic waterproof seals around showers and sinks.
Once your sealant is applied, you'll want to smooth out the silicone. You can use a damp piece of wood, a specially designed smoothing tool, or a finger dipped in soapy water to smooth out and shape the sealant.