Tile Ratings

Wall tiles, unlike floor tiles do not have to bear weight, not they need to withstand heavy traffic. So they can be thinner, and have more refined finishes.

Wall tiles on the other hand, shouldn't be used on floors or countertops for the same reasons. they won't be able to resist to a sharp impact or too much weight.

Before you decide what tiles to buy, ask the retailer about some tile ratings: how do they react in contact with water; or based on the manufacturing quality, what is their grade. The answer to these questions will help you to decide the right type of tiles you need to buy.

We did some research and put together this short "guide" for you:

Types of Tile Ratings

You might hear the salesperson in the tile store mentioning Tile Grades

The American National Standard Institute(ANSI) establised a grading system for tiles sold in United States, and produced here or elsewhere.
According to them we have:

Standard Grade - it meets minimum requirement set by ANSI

Second Grade - these tiles are structurally standard, but there are present minor imperfections in the glaze or shape

Decorative thin wall tiles - they are suitable just for walls and it shouldn't be put to any functional use.

Most tiles intended for walls come with a Water Absorbtion Rating.
Absorbtion is a concern because if the tile will soak up water, it will be susceptible to mildew and mold. The amount of absorbed water depends on the amount of air pockets in the tile's bisque. Thre are four types of tiles:

Non-Vitreous Tiles - quite porous, these tiles absorb around 7% water, out of their weight. They are fired at realtively low temperatures, so the costs to manufacture will be lower; hence the price lower than the vitreous ones. because oh high water absorbancy, they might not get a chance to dry between uses, so bacteria might develop. Not suitable for wet areas. may need sealant.

Semi-Vitreous Tiles - Fired at almost the same temperature as the non-vitreous one, but for longer time, will make them less porous, and they absorb somewhere between 3 to 7% of their weight. They might need to be sealed. Sealant changes the appearance of the tiles, so testing is recommended.

Vitreous Tiles - Fired at higher temperatures and for longer than the previous ones, they absorb only between 0.5 and 3% water of their weight. They are suitable for wall installations, and floor installation due to their higher density( not so porous).

Impervious Tiles - absorb less than 0.5% water, so they are almost waterproof. Suitable for any installations.

Another system used for rating tiles is the Wear Rating System, developed by Porcelain Enamel Institute(U.S.). According to them we have:

Group I - If soft footwear is worn, they are suitable for residential bathroom installation.

Group II - Suitable for residential use, but excepted in heavy use areas such as kitchens, entrances.

Group III - Suitable for all residential areas and light commercial ones.

Group IV - Suitable for all commercial areas and light institutional ones.

Group V - Suitable for areas where maximum safety and performance is required.

One of the other types for tile ratings is Resistance To Frost. You might want to know about this one, specially if you live in a freeze zone, and plan for an outdoor wall tile installation. If the rating is not specified on the packages, the retailer should be able to tell you more about it.