Nothing undoes a beautiful tile job faster than grout lines that crack, pit, and pull away from the tile a few months after installation. That shrinkage is one of the most common grout failures, and it traces directly back to the type of grout used and how it cured. Non shrinking grout refers to grout formulations, primarily epoxy and premixed urethane products, that cure without the volume loss that plagues traditional cement grout, giving you tight, consistent joints that stay put. Understanding why standard grout shrinks and which alternatives resist it will save you the headache of re-grouting and the water damage that failed joints invite.
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This guide explains what causes shrinkage, the grouts that avoid it, and where and how to use them.
Why Traditional Cement Grout Shrinks
Standard cement-based grout is mixed with water, and as that water evaporates during curing, the grout loses volume, that is shrinkage. On a small joint the effect is minor, but on wider joints, in fast-drying conditions, or when the mix is too wet, the grout can shrink enough to crack, crumble, or separate from the tile edges.
Improper mixing makes it worse. Adding too much water to make the grout easier to spread, or adding water after it starts to set, dramatically increases shrinkage and weakens the finished joint. Uneven drying, from a floor that gets sun on one side or heat from a nearby vent, causes differential shrinkage that cracks the lines.
Epoxy Grout: The Gold Standard for No Shrinkage
Epoxy grout is the top performer when you want joints that will not shrink. Instead of cement and water, it uses epoxy resins and a hardener that cure through a chemical reaction rather than by drying out. Because no water evaporates from the joint, there is essentially no shrinkage.
Epoxy grout also brings other advantages that make it worth the higher price and trickier application:
- Waterproof and stain-proof: Ideal for showers, backsplashes, and countertops.
- No sealing required: The resin is non-porous, so you never seal it.
- Color consistency: It holds its color without the blotchiness cement grout can develop.
- High strength: Resists chemicals, abrasion, and cracking.
Premixed Urethane Grout
Single-component urethane grouts come premixed in a bucket, ready to spread straight out of the tub. Like epoxy, they resist shrinkage far better than cement grout, and they are considerably easier to work with, no mixing, no short pot life, and easier cleanup.
Urethane grout is a great middle option: more forgiving than epoxy for a DIYer, stain-resistant, and no sealing needed. The trade-off is that it cures by releasing moisture, so it is not recommended for continuously wet areas like a steam shower or a pool, and it needs good airflow to cure fully. For a typical kitchen backsplash or a bathroom floor, it performs beautifully.
Where Non Shrinking Grout Matters Most
Shrinkage-resistant grout is worth the premium in specific situations where failed joints cause real problems:
- Wet areas: Showers, tub surrounds, and steam rooms, where cracked grout lets water reach the substrate.
- Wide grout joints: Joints over 1/8 inch, where cement shrinkage is most visible.
- Countertops and food-prep surfaces: Where you need a hygienic, stain-proof, waterproof joint.
- High-traffic floors: Commercial-style entries and kitchens that demand durable joints.
- Large-format tile: Where consistent, crack-free joints keep the modern look clean.
Getting Cement Grout to Shrink Less
If budget or availability means you are using traditional cement grout, you can minimize shrinkage with good technique. Mix to the manufacturer’s exact water ratio, never eyeballing a wetter mix, and let it slake for the specified time before use. Use a polymer-modified or “high-performance” cement grout, which is formulated to reduce shrinkage and improve strength.
After grouting, control the cure. Mist the joints lightly with water over the first day or two in hot, dry conditions to slow evaporation and reduce cracking, a technique called wet curing. Keep direct sun and heat off the fresh grout while it sets.
Application Tips for Epoxy and Urethane
Non shrinking grouts apply a little differently than cement. Epoxy is sticky and has a limited working time once mixed, usually 45 to 60 minutes, so mix only what you can install in that window and work in sections. Spread it with a hard rubber float at a 45-degree angle, pack the joints fully, and clean the tile face promptly with the special detergent and scrub pads the manufacturer supplies, because cured epoxy on tile is very hard to remove.
Urethane is more forgiving, spread it, tool the joints, and clean up with water before it skins over. With either product, do not add water to thin epoxy, and follow the recommended temperature range, typically 60 to 90 degrees Fahrenheit, for a proper cure.
Cost Comparison
Non shrinking grouts cost more up front but often save money over the life of the installation:
- Cement grout: $12 to $20 per bag; cheapest but shrinks and needs sealing.
- Premixed urethane: $25 to $45 per unit; no mixing, no sealing.
- Epoxy grout: $30 to $60 per unit; the most durable and shrink-resistant.
Factor in that epoxy and urethane never need sealing and rarely need repair, and the higher material cost pays for itself in a wet area or a busy kitchen where cement grout would fail early.
Movement Joints: The Overlooked Companion
Even the best non-shrinking grout is not meant to absorb structural movement, and expecting it to is a common cause of cracked lines. Tile assemblies expand and contract with temperature and humidity, and they need dedicated movement joints, sometimes called expansion or soft joints, to handle that shift. These are filled with a flexible color-matched silicone or caulk rather than rigid grout.
Place movement joints where the industry standard TCNA guidelines call for them:
- Perimeter joints: Wherever tile meets a wall, cabinet, or fixed object, leave a soft silicone joint, never rigid grout.
- Inside corners: Where a floor meets a wall or two walls meet in a shower, use flexible caulk.
- Changes of plane and material: At transitions and over control joints in the slab below.
- Large fields: Every 20 to 25 feet indoors, and more often in areas with sun or temperature swings.
Get the movement joints right and your non-shrinking grout does its job for decades; skip them and even premium grout eventually cracks where the assembly needs to flex.
The Bottom Line
Non shrinking grout, epoxy for the toughest wet and food-prep areas, premixed urethane for easier everyday jobs, gives you tile joints that stay tight, waterproof, and crack-free without the shrinkage that undermines cement grout. Use it wherever failed joints would cause real trouble, in showers, on countertops, and across wide joints. If you must use cement grout, mix it precisely and wet-cure it to limit shrinkage. Choose the right grout for the location and your tile job will look as good in ten years as it did the day it was finished.
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