Interior wall tiles are a type of ceramic tile, primarily used for indoor wall decoration. They consist of three parts: the body, the bottom glaze layer, and the top glaze layer. The water absorption rate of the body is generally around 10-18%. The weight of the bottom glaze is 40-60 grams, and the top glaze is 90-160 grams. In general, the higher the firing temperature, the greater the top glaze weight, resulting in better brightness and a smoother surface for the tile. Of course, the quality of the glaze also has a significant impact.

Inspection Standards: 1. For wall tiles, there should be no hollow spots. While hollow spots are permissible at the edges of tiles, the total number of hollow spots in a single room should not exceed three. You can use this standard to inspect the wall tiles in our indoor kitchen and bathrooms.

2. The standard for verticality is that the verticality of the tile's facade must be within 3mm. Otherwise, it is不合格.

3. The standard requirement for flatness is that the tiles must not have an error in flatness exceeding 2mm. Additionally, the height difference between adjacent tiles is not allowed to exceed 0.5mm. Tiles exceeding the error are considered不合格 (unqualified), and we can request them to be removed and re-laid.

4. The levelness or perpendicularity error in tile joints must not exceed 0.5mm. In fact, it's visible to the naked eye if it does. Additionally, measure the perpendicularity and levelness of tile joints before applying the decorative grout, as the grout can cover up imperfections, making it difficult for us to measure later.