Grout is the material visible between tiles. It is used to fill the space between the tiles and to support them. Grout can be water-resistant. However, water or other liquids, will most likely penetrate the joint and reach the backing. There are three major classifications of grout:
Portland cement based grouts
Furan resin grouts
Of these three, 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
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. Starlike® Speciality Grout can be used on virtually any surface and is easy to apply. Also, carefully following the Manufacturers instructions in mixing and applying will ensure a successful installation.
SANDED-PORTLAND CEMENT GROUT
Tile Doctor Tip: When the application involves ceramic or stone tile which is easily scratched, as in the case of polished marble, an attempt should be made to use non-sanded grout to avoid scratching the finished surface.
This is an on the job mixture of cement, fine sand and water. Its specifications are found under ANSI 108.10 2005. On the job mixes are used for large jobs and normally can only be mixed in white or gray. The color is dictated by the cement color used.
The following three grouts are commercially prepared grout available from a variety of manufacturers. The following Portland cement based grouts are the most common grout used for installations that do not require any special considerations. They are covered under ANSI 118.6 2005.
NON-SANDED PORTLAND CEMENT DRY-SET GROUT
Tile Doctor Tip: When grouting in hot weather, be sure to use cool water to keep the grout as cool as possible. Shade the work area to lessen the overall temperature. These steps will keep the grout from curing too rapidly.
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
Tile Doctor Tip: Do not be misled by the term dry set. All Portland cement grouts can benefit from careful installation practices. Moistening the tile and damp curing is always recommended when using Portland cement grouts. However, always follow the Manufacturers recommendations and instructions.
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
Tile Doctor Tip: Damp curing is best accomplished with a Kraft paper type product as opposed to a plastic product. Plastic will form condensation that will drop back into the joints of grout causing uneven curing and discoloration. Kraft type paper does not accumulate water between the tile and paper.
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.
Tile Doctor Tip: To avoid the grout haze problem: Always mix grout according to the Manufacturers instructions, allow to slake at least 15 minutes, apply according to text and photos in The Tile Doctor, tool with an almost dry sponge, wipe at a 45° angle with an almost dry sponge, and then buff the tile with cheesecloth after the grout is initially set.
Introduce as little water as possible during the grouting process.
Note: Modern 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.
The following grouts do 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. 100% epoxy grout is described under ANSI 118.3 2005.
MODIFIED EPOXY GROUT
This grout has an additional ingredient of Portland cement. The characteristics of this grout are similar to standard Portland cement grouts. However, they are harder, form greater bonds, and are more stain resistant. They are not necessarily any better than Portland cement based grout in their resistance to chemical attack. Modified epoxy grouts are described under ANSI 118.8 2005.
Tile Doctor Tip: These grouts are more expensive and more difficult to install than standard Portland cement grouts. Also, when chemical resistance is the goal, the actual chemical involved should be considered and tested against the intended grout ingredients. This will ensure that the intended grout can resist the chemicals that will be present in the finished job.
The name furan comes from the ingredient in the grout called furfuryl alcohol. This means that no water at all is used in the mixture. It is generally considered to be highly chemically resistant especially when acids are the problem to be encountered. They are much more difficult to install than any other grout. The tile must be coated with wax prior to grouting and the grout residue removed with steam cleaning following the grouting process. Normally, the grout is manufactured in a black color only. Bare in mind that furan grout will react with some chemicals that epoxies will not and visa versa.
Again, careful consideration is necessary in establishing what chemical needs resisting. Furan grout are described under ANSI A 118.5 2005.The are other grouts in a class all by themselves. These include grouts that are the pre-mixed liquid types that are available in a variety of container types. They may or may not contain silicon or other products. They are available in a sanded or non-sanded configuration.
CAULKING-TYPE OF GROUT
There is a very popular type of grout in this class that includes the caulking type of grout that is available in tubes squeezed by hand or designed for use in a caulking gun. These grouts can be very close to the color of Portland cement grout in the tiled installation. They are used to caulk abutting surfaces like the joint between a tile wall and tub, a kitchen sink and counter tile, or the 90° corner joints where tile meets tile.
When selecting setting and grouting materials, special care must be given to the selection process. Use the best products that the budget will allow. Always follow the Manufacturers instructions concerning the use and application of the chosen products.