NITTAI Co., Ltd.

Quality of Tile

A

Dirt in the air and sealing material that has adhered to rain streaks

Dirt in the air, sealing material that has adhered to rain streaks, exhaust fumes, soot and smoke, and other soiling adhere to the wall surface and concentrate in locations in which rainwater flows. The stains remaining in the streaks can be removed only by water washing and wiping. Also use a neutral detergent for stains that contains exhaust fumes and other oil-based components.
Low molecular-weight components in silicone sealing material, such as that around sliding window frames, dissolve and scatter to the surroundings by rainwater and other liquids. The components trap dust in the air to form stains or becomes stains themselves. These stains can be removed by brushing and washing with a neutral detergent, but the stains may return again.

B

Stains from the adhesion of calcium carbonate, etc.

The calcium carbonate is created following the hardening reaction of mortar and concrete. Most is considered efflorescence. Use the product “Actole” to remove efflorescence. For the product “Actole”, inquire at one of our business offices.

C

Stains from the adhesion and solidification of silicon dioxide

Silicon dioxide, carbonate, and sulfate in cement and the air that adhere to a tile surface are transparent, but the interference of light generates an iridescence phenomenon through which an oil film of the colors of the rainbow can be seen. Carbonate and sulfate can be removed through washing with water or dilute hydrochloric acid, but silicon dioxide is often difficult to remove. This type of stain forms on all types of tiles, but it tends to be particularly conspicuous on metallic luster tiles and dark-colored tiles.

Iridescence phenomenon

What is the iridescence phenomenon?

An extremely thin film (500-2,000 Å) forms on the tile surface, and rainbow colors shine on the surface. The film is mainly the crystallization of alkalis (from the same cause as efflorescence) or silica material (SiO2) that dried and solidified on the tile surface. The main alkalis include calcium carbonate, magnesium carbonate, sodium sulfate, and potassium sulfate. The iridescence phenomenon occurs easily particularly on very smooth, high quality tile with a low water absorption rate and glossy surface. It is very likely that air pollution is a negative influence for the iridescence phenomenon. Increases in sulfur dioxide and carbon dioxide gas stimulate the crystallization of alkalis, and smoke dust in the air and adhered silica material are also causes.

● Possible tangible causes in the case of alkalis

  • Shore sand was used

    Soluble salts from shore sand (NaCl, etc.) move with moisture and are deposited on the surface.

  • Excessive mortar kneading water

    If there is a lot of kneading water to the extent that there is floating water, the excess moisture must leave the tile surface or joints, and soluble salts are carried to the surface at this time.

  • Penetration of water into the tile rear surface

    If water penetrates into the rear surface of the tile during rainfall, soluble salts separate when this water comes out. It is necessary to fill the rear surface of the tile with mortar thickly and pack so that there are no gaps even in the joint sections.

  • Soluble salts are contained in the kneading water / washing water.

● Possible tangible causes in the case of silica material

  • Silica components in the washing water

    Silica components that have dissolved in the washing water dry and solidify on the surface, forming a film. Silica components are dissolved in large quantities in well water in particular.

  • Insufficient wiping of the cement on the tile surface

    Moisture and carbon dioxide dissolve cement minerals to form calcium carbonate and diluted silicic acid, which dries and solidifies on the tile surface, forming a film. It is also believed that cement of the tile joints and rear surface dissolves in the same way, and diluted silicic acid dissolves into water, which dries and solidifies on the surface, forming a film.

  • Penetration of water into the tile rear surface

    If water penetrates into the rear surface of the tile during rainfall, soluble salts separate when this water comes out. It is necessary to fill the rear surface of the tile with mortar thickly and pack so that there are no gaps even in the joint sections.

  • Adhesion of silica components in the air

    Smoke dust (silica components) in the air penetrates rainwater, and then dries and solidifies on the surface, forming a film.

Countermeasures when the iridescence phenomenon has occurred

Cleaning using Clinston products is effective. For Clinston products, inquire at one of our business offices.

Adhesive residue

In the case of paper face-mounted tiles, always wash off the glue when peeling the paper and before packing joints. If glue washing is insufficient, and glue remains on the tile surface, color spots may be seen, and the beauty of the surface may be lost. Furthermore, if glue still remains when joints are packed, washing cannot be performed successfully, which causes staining of the joints.

● Precautions when peeling the paper

When peeling the paper, moisten sufficiently with water for about three minutes, make sure that the glue of the tile surface has softened, and then peel the paper slowly.

● Precautions when wiping joints

Wipe immediately after filling the joints. When both roughly and finely wiping, use a sponge or other appropriate tool to wipe the tile surface clean of the remaining joint material. Be aware that if the joint material is left for a long time on a very irregular surface, the joint material can no longer be removed. Just after filling the joints, use water or dilute hydrochloric acid with appropriate curing and cleaning tools.

Efflorescence

White cotton-like roughness or specks form from the tile and tile joint sections.

● Cause

The main cause of efflorescence is external water penetrating when there are gaps in the rear surface of the tile or cracks in the wall surface.

● Important points

Efflorescence is likely to occur where water can easily penetrate, such as the lower parts of cracks and around windows. Therefore, it is important to prevent water from penetrating.

1) Build control joints so that cracks do not occur.

2) Do not overlook the sealing of openings.

3) Fill with mortar completely so that there are no gaps in the rear surface of the tile when tiling.

● Removal method

Use the product “Actole”. For the product “Actole”, inquire at one of our business offices.

Soiling from acid after work with black-colored tile

Washing with dilute hydrochloric acid may be performed during the cleaning stage of wet construction work with ceramic tiles. In the case of black-colored tile, when standard construction methods are not observed during this stage and hydrochloric acid components remain on the tile and joint material, dark reddish-brown stains may form in joint sections slowly over time. Be aware that soiling is conspicuous particularly when white joints are used.

Main causes

  • During the cleaning stage, sufficient washing or moistening with water was not carried out or moistening was not sufficient.
  • The concentration of dilute hydrochloric acid was higher than specified.
  • Water washing was not sufficient after acid washing.

Occurrences are frequently seen particularity when rainwater hit the tile after completion.

During cleaning after construction, moisten sufficiently so that no hydrochloric acid components remain, and then carry out after‐treatment, such as washing with water.

Flow of standard specification works

End of joint placement

Sufficient curing

Sufficient washing/moistening with water

Acid washing with 30x diluted hydrochloric acid

Sufficient washing with water

Color changes from acid after work with blasted tiles

Projected stainless steel ball fragments partially remain on ceramic tile that underwent blasting to roughen the surface. These are metal fragments, and they microscopically stick with strong force. Washing with dilute hydrochloric acid may be performed during the cleaning stage of wet construction work with ceramic tiles. Hydrochloric acid components react with the remaining metal fragments at this stage, and the color of the tile surface may be changed. Be aware that this change may cause yellow and orange specks to appear, particularly with white and light-colored tiles.

However, these changes do not occur immediately after washing. Some time (1 to 3 days) is necessary. As a countermeasure, changes can be avoided by moistening before acid washing, and then washing with water sufficiently. Please be sufficiently aware of this point when acid washing will be performed on blasted tiles.

  • Frost damage

    When moisture freezes, volume expands about 9%. When water absorbed by tile material freezes and thaws repeatedly, cracks, peeling of the outer layer, and other damage occur. In cold regions, frost damage may occur even indoors in places that are splashed with water (such as bathroom walls). Make a decision based on the freeze-thaw resistance suitability mark when choosing tile. In the case of interior locations not splashed with water, tiles without the freeze-thaw resistance suitability mark can be used.

    Airtight curing and maintenance of polished tiles

    Construction precautions

    When installing and curing polished tiles, allow adhesives, pasting mortar, cement paste, and joint material to harden and dry sufficiently first. When airtight curing was performed with corrugated plastic without sufficient drying, high-alkalinity condensation that contains cement and other components may adhere to the tile surface and decrease the tile surface luminance. (Once the luminance has declined, it is difficult to return it to its original state.)

    Maintenance

    Do not clean using melamine foam, a chemical mop, or similar items. These items cause tiny scratches on the tile surface, and solvent components that are attached to mops and other items may reduce the luminance. (Once the luminance has declined, it is difficult to return it to its original state.)There is a protective layer on the tile surface to protect its luminance. Avoid commercially available waxes and other coatings.

    For daily maintenance, wipe using a cloth or similar item with water or a neutral detergent.
    Do not use acid or alkaline detergent.