WHAT IS THE DIFFERENCE BETWEEN URETHANE AND CEMENT-BASED GROUT?

Both products have a fine aggregate, usually fine silica (quartz) sand, as the foundation of the product. This sand is what really produces the strength and durability of grout. Silica has a hardness of seven on the Mohs scale, and not too many naturally occurring things are harder than quartz. When sanded grout is dry and you rub your finger across it, you feel this sand.

Urethane grout is premixed. You open a bucket, stir it to fold in any of the urethane polymer that’s separated during shipment and immediately get to work. Cement grout is a powder you mix with water. If you add too much water, you can significantly reduce the final strength of the grout. Unequal amounts of water in different batches can lead to mottled coloration of the dried grout. Cement-based grouts also release dust into the air when you pour and mix them.

Urethane grout use polyurethane resins and polymers as the binder to hold together the sand particles. Traditional grout uses Portland Cement.

DO THEY BOTH COME IN A VARIETY OF COLORS?

The pigments in urethane grout are a special coating that’s permanently bonded to each of the fine sand particles. The finished colors of the grout are solid colors that are ultraviolet stable. They will not yellow nor fade when exposed to harsh sunlight that might stream through a patio door. Pigments in traditional grouts are powder additives that colorize the cement which then coats the silica sand. It can wear off over time. You’ll see this on older grout floors as the sand particles look light, even white in color.

ARE THEY INSTALLED THE SAME WAY?

Because urethane grouts air dry, you have to wipe off any excess grout film quickly from the tile surface. It’s best to just work a small area of probably 10 square feet at a time. Always squeeze all the water from a sponge as you gently wipe and film from the surface of the tile. Excess water can weaken urethane grout.

The drying or curing time for these urethane grouts is about the same as cement-based grouts, however in very humid locations the curing time will be longer. They’ll not achieve a great hardness until the water in the emulsion has a chance to evaporate. Simply follow the instructions on the product label and you will be fine.

WHY URETHANE GROUT?

Urethane grouts are slightly more expensive than cement-based products. However, factor in that the urethane grouts are more flexible than traditional grout. If there is future movement, a cement-based grout will usually develop a hair-line crack. The urethane grout is more likely to withstand that stress without cracking.

If you are a novice and don’t know how to mix grout, the urethane grout takes away all that worry. You simply open up the bucket, mix and spread. If you have any leftover, you can save it if you follow the directions on the label. Once traditional cement-based grout is mixed with water, it will harden. You can save leftover dry cement-based grout, but you must tightly seal it so that humid air will not react with the cement powder.

WHAT IS THE STANDARD FOR DETERMINING THE SIZE OF A GROUT JOINT?

Ceramic and natural stone tiles always ned to be installed with a gap know as a grout joint, between each tile. 

Understanding the importance of this is crucial for all tile installations. ANSI ( American National Standards Institute) sets the standard for grout joints in A108.02 Section 4.3.8, specifing that the grout joint should never be less than 1/6″ ( 1.6 mm)

Due to tile size variations, the actual grout joint width may need to differ from the inital request, and should be three times the variance in the actual tile face dimentions. 

CALCULATING RECOMMENDED GROUT JOINT SIZE:

Example: