INSTALL MOSAIC

Save time by carefully following these instructions for installing mosaic tiles.

General Conditions

With any tile installation, begin by evaluating the site conditions: temperature and humidity, substrate and waterproofing. For exterior installations you will evaluate the options of either partial or total covering. The substrate must by correctly aged; normal site practice suggested by adhesive manufacturers is to wait 28 days for the underlay and cement-based plasters or 90 days for concrete. With anhydrite-based substrates, allow a maximum of 0.5% residual humidity.

It is also very important to take into account the possible effects of temperature on adhesives and materials. At temperatures below 10° C, proper drying of the adhesive would be considerably slowed down and could create problems for bonding in the long term; at temperatures over 35° C it is advisable to carry out the installation at a time day with less sun, generally in the morning or late afternoon. Shield the site from excessive sunlight during the hottest parts of the day to prevent possible dehydration of the adhesive.

It is equally important to consider the dehydrating effect of wind, especially during the installation of exterior facades or on boats. In the case of swimming pools it may be necessary to test the bonding to evaluate the behaviour of the structure adequately. Shower floors and Jacuzzi tubs must be waterproofed with special products. Before smoothing and laying, all traces of dirt, oil, etc. must be carefully removed. In addition, all loose parts must be eliminated and the surface powder removed. 

Technical Instruments For Installing Mosaics

Before beginning, check that all the instruments are clean and without rust.

  • Angle grinder with crown diamond–continuous cutting disc.
  • “Special” diamond disc for cutting mosaics, diam. 110 mm.
  • Measuring set: tape measure and pencil.
  • String for marking the main reference grid.
  • Mosaic pliers and cutters.
  • Set of various-sized trowels - Floats.
  • Toothed spreader (Choose the one suitable for the material to be laid and the
    type of support to be used).
  • Rubber float for grouting and felt-backed float.
  • Basin with roller and sponge for cleaning.
  • Low speed mixing drill with spiral mixer, necessary to ensure than the
    properties of the adhesives remain consistent.

Substrate Preparation

The substrate must be compact and free of cracks. If there is a tendency to flake or if it is warped from shrinking, it will not provide adequate support for the installation and correct Skimming must be carried out first. Skimming is also necessary in all cases where the base is not perfectly flat. With TREND adhesive, it is possible to produce rendering up to 5 mm to correct small defects of the substrate; this operation must be carried out at least 24 hours before installing the mosaic.

Unless otherwise specified by the customer, the mosaic is usually installed on white adhesive to avoid altering its color. If the substrate is grey (especially dark grey), it is advisable to skim it with white adhesive to make the color of the substrate uniform before beginning to install the mosaic.

Installing Mosaic

Every installation begins with unpacking the mosaics. It is advisable to verify the condition of each sheet of mosaic contained in the boxes before beginning the installation, and it is good practice to keep the same temperature as the surroundings.

The starting point is then identified and marked on the wall where the mosaic will be installed. Mark the guidelines at right angles to each other corresponding to the multiples of the sheets of mosaics previously measured. 

Once the reference grid has been marked, the adhesive is spread over the base. First use the smooth edge of the notched spreader to ensure that the whole surface is covered. Excess adhesive is then removed using the notched edge of the spreader (3 mm square teeth), being careful to keep a steady inclination of the spreader and exerting sufficient pressure so that no more adhesive than necessary remains on the base.

Installing Mosaic on Film

Once the reference grid has been marked and the adhesive spread over the base, the actual installation begins by applying the mosaic sheet with the plastic film facing towards the operator (not towards the surface) and without exerting too much pressure.

Tap the mosaic with the rubber float to ensure perfect adhesion to the surface. During this operation it is possible to correct any minor errors that might have been made in the alignment by lightly tapping sideways on the sheets.

The adhesive must not run over the joints. If this happens, it means (1) that the notches on the spreader are too large; (2) that the base is not perfectly flat and in some points there is excessive adhesive; or (3) that the notched spreader is not being used correctly.

During the installation some manual manipulation on the sheets of mosaics may be necessary.  When this is required, the installer simply removes a single tile and substitutes it with another, being careful to ensure that the adhesive is still workable.

The plastic film is removed from the mosaic only when the adhesive is sufficiently hardened; the suggested time is approximately three hours. The motion should be carried out diagonally, keeping the film parallel to the mosaic . If during the removal of the film the mosaic moves, it is necessary to wait longer.

Installing Paper Face Mounted Mosaic

If the mosaic is face mounted , the paper should be facing the installer.

It will facilitate the installation if you position the stripes from the paper vertically on the surface.

It is important during the installation  to keep the same distance between the sheets . Once the sheets are installed, use the rubber float to tap the mosaic into the adhesive and use the proper trowel to flatten the sheet.

The removal of the paper is performed using warm water and a sponge. Repeat the gentle sponging operation in the area you are working until you can remove the paper easily. You can also use a steamer to facilitate this process. Work carefully, because at this stage the adhesive may still be relatively fresh.

When removing the paper, pull diagonally from one top corner to the opposite bottom corner of the sheet. Grout lines can be adjusted before the adhesive cures.

Grouting and Final Cleaning

Allow the adhesive to set before filling the joints: 24 hours for vertical walls and 48 hours for floors.

Using the rubber float, spread the grouting cement with vertical and horizontal movements applying a slight pressure to make sure the joints are well-filled. Use the rubber float diagonally to remove most of the excess filling.

The  surface  can be cleaned once the grout is dried.  This time will vary according to the temperature of the surroundings, but will be between 30 and 60 minutes. Remove the excess grout using the special felt and a slightly dampened sponge; at all times be careful not to remove the filling from the joints.

It is very important to carry out this operation before the grout has completely hardened. Any eventual residue can be removed with a special acid-based product 

Be sure to rinse everything thoroughly after this operation to avoid leaving traces of acid.

If there are any traces of adhesive on the mosaic, remove the dry excess with steel wool.

Technical Information Catalogue

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