Grout is the material that fills the joints between tiles. Grout can be water-resistant. However, water or other liquids, will most likely penetrate the joint and reach the backing. The best thing is to ALWAYS seal your grout and it is a maintenance issue to be done every 2 to 3 years. There are two major classifications of grout: Portland Cement Grout and Epoxy Grout.
Of these two, there are two basic types: sanded or non-sanded. Sanded grouts should be used when grout joints are 1/8" or larger. Non-sanded grouts should be used in a joint 1/8" or smaller. Sanded grouts-grout joints 1/8" or larger and Non-Sanded grouts-grout joints 1/8" or smaller.
The following information details the individual grout types encountered in this area. Selecting the right grout for the job is as important as selecting the right tile and backing. Also, carefully following the Manufacturers instructions in mixing and applying will ensure a successful installation.
NON-SANDED PORTLAND CEMENT DRY-SET GROUT
This grout consists of Portland cement, fine fillers, a water-retentive additive, and colored pigments. This grout is designed for use in tile surfaces that are dry when the grout is applied. The water retentive additive allows the grout to stay moist until the cement cures properly. Without the additive, the dry tile would wick out the water before the cement can cure. Generally, this grout is used for easily scratched tiles and for wall use in joints from 1/32" to 1/8".
SANDED PORTLAND CEMENT GROUT
This grout consists of fine graded sand, Portland cement, sometimes water retentive additives, and colored pigments. This grout should be applied to moistened tile, no puddled water in the joint, and damp cured.
LATEX-MODIFIED SANDED PORTLAND CEMENT GROUT
This grout is the same as the above grout. However, a latex polymer is either incorporated into the pre-mixed powder or added during mixing. This grout has increased water resistance and bonding characteristics.
Most grout manufacturers have developed their products to be as water-resistant and uniformly colored as science allows. Again, they want the grout and other products they produce to succeed. There again, it is still recommended to SEAL your grout.
The following grout does not have Portland cement as their hardening/curing substance. They have special attributes necessary or desirable in some installations. Normally, the applications involve the necessity of chemical or thermal resistance. These grouts also have sanded and non-sanded type fillers for varying joint widths. However, sand is normally replaced as the filler with minerals designed to resist the specific chemicals called for in the installation.
100% EPOXY RESIN GROUT
Like the name suggests, this grout is 100% epoxy. While no water is present in the mixture, clean up is still accomplished with water. The grout consists of epoxy resin, silica fillers, pigments, and a hardener. These grouts are resistant to staining, have very low water absorption, and have higher compressive strength than concrete. 100% epoxy grouts are also highly resistant to chemical attack. This is ideally the way to go. The price is much higher, but in the end it will save you time and energy. The color will not fade and will be aas beautiful as the day you installed it.