How Are Tiles Made Step By Step?

Tile making has a long and rich history dating back thousands of years. Some of the earliest known tiles were made in ancient Egypt and Mesopotamia around 4000 BC. These early tiles were handmade from clay and used to decorate palaces, temples, and homes.

The basic process for making tiles has remained relatively unchanged over the centuries. The main steps include clay preparation, molding and pressing the tiles, drying them, glazing if desired, and then firing in a kiln. Firing the clay is the most important step, as this hardens and sets the clay into a finished tile. Once fired, tiles may be polished and have finishing touches applied.

While the fundamentals are the same, tile manufacturing today is highly automated, allowing greater precision and higher outputs. The scale of production has increased dramatically from small batches made by hand to mass production in factories. A wide range of materials like ceramics, porcelain, glass, metal, and stone tiles are now manufactured.

This article will walk through the typical manufacturing process for ceramic and porcelain tiles step-by-step from raw materials to finished products. It provides an inside look into how one of the most ubiquitous building materials is made.

Clay Preparation

The clay used to make tiles goes through an extensive preparation process before it is ready for molding and pressing. This process starts with digging the clay from quarries using heavy machinery like excavators. The clay is then transported to processing facilities where it undergoes the following steps:

Crushing and grinding – The excavated clay contains rocks and mineral impurities. Powerful crushers are used to break down the clay into smaller fragments. These fragments are then fed into grinders that pulverize the clay into a fine powder.

Mixing – The powdered clay is then mixed with water in blungers which are high speed mixers. This mixing process dissolves any remaining mineral impurities and creates a smooth, plastic consistency optimal for molding.

Degassing – Any air bubbles trapped in the clay mixture are removed using a vacuum degassing system. This gives the clay plasticity and prevents cracking and weak spots in the final tile product.

Filtering – The clay slurry is passed through filters to remove sticks, gravel and other foreign particles.

Additives – In addition to clay, certain chemicals and minerals are added to the slurry to enhance specific properties. For example, feldspar is added to improve firing performance, while grog (ground, fired clay) is added to limit shrinkage.

The prepared clay resulting from this extensive process provides an optimal base material to shape into high quality tiles.

Molding and Pressing

Once the clay has been properly prepared, the next step is to mold and press the clay into the desired tile shapes. This is done using molds that can be made of various materials like plaster, resin, wood, metal, or silicone. The molds are created by carving or sculpting the negative shape of the tile design.

There are two main techniques for pressing clay into the molds:

Pressing by Hand

For hand pressing, balls of clay are pressed into the mold cavity to pick up the pattern. The clay is pressed firmly into the mold using fingers and tools to ensure it fills every crevice. Hand pressing is often used for intricate, detailed molds or small production runs.

Machine Pressing

For large-scale tile manufacturing, hydraulic pressing machines are used. The prepared clay is fed into a hopper above the mold. A hydraulic ram then applies immense pressure to press the clay into the mold cavities with precision and consistency. The machines allow high-volume tile production.

Whether pressed by hand or machine, the wet clay picks up the exact negative shape of the mold design. The molded tiles are then ready for drying and firing.

Drying and Firing

After the tiles have been molded and shaped, the next step is to carefully remove the moisture from them before they can be fired in a high heat kiln. Removing the moisture, known as drying the tiles, is a delicate process that ensures the tiles do not become damaged or cracked during firing.

Tiles are left to air dry for several days, either on racks or placed loosely on the floor of a warm, well-ventilated room. The temperature and humidity levels must be closely monitored to facilitate slow, even drying. Rushing the drying risks uneven shrinkage or warping of the tiles.

Once fully dried, the tiles are ready for firing in an industrial kiln. Temperatures inside the kiln can reach over 2000°F. Firing serves two essential purposes – it sets the shape of the clay permanently, and it fuses any glazes or coatings to the body of the tile. Firing is done in stages, gradually increasing and then decreasing the temperature over the course of hours or days. Carefully controlling the firing transforms the clay into a strong, durable ceramic material ready for final polishing.

Glazing

After firing, the tiles are ready to be glazed and decorated to give them color and finish. Glazes are mixtures of silica, fluxes, and colorants that melt and fuse to the surface of the tiles during a second firing process. They create a glassy coating that is decorative but also waterproof and durable.

There are many techniques for applying glazes and decorative finishes to tiles:

Dipping – The tiles are dipped into a bucket or tub of liquid glaze. The glaze thickness is controlled by the viscosity of the glaze and the speed of dipping. Multiple dips can increase glaze thickness.

Brushing – Glazes are applied with a soft brush. Different brushing techniques like cross-hatching or stippling create textured effects.

Spraying – Glazes are spray applied using a pressurized spray gun or spray booth for consistent, all-over coverage.

Screen printing – Decorative designs and patterns are applied through silkscreen stencils using glaze as the printing medium.

Sponging – Sponges are used to dab glazes onto the tile surface for mottled textures.

Rolling – Glazes are rolled onto the tiles with paint rollers to build up layers of color.

These application methods allow for endless creativity in tile design. The glazing and finishing process is key for achieving the desired decorative effects.

Polishing and Grinding

Once tiles have been fired, they may still have small imperfections and uneven surfaces. The polishing and grinding process helps smooth and finish the tile surfaces.

Tiles are first fed through grinding machines which have abrasive rollers or belts. These remove any bumps or ridges in the surface of the tiles. The abrasives leave small scratches in the tile surface as they grind it down.

After grinding, tiles undergo polishing which uses progressively finer abrasives to smooth out the surface even more. This leaves the tiles with a glossy, smooth finish. Polishing wheels and belts contain diamond or silicon carbide abrasives in successively finer grits. The final polishing step often uses an extremely fine abrasive paste for a mirror-like surface.

Automated optical scanners detect any defects in the tile surfaces after polishing. Expert workers also manually inspect a percentage of the polished tiles for quality assurance.

The polishing and grinding process is critical for making sure tiles have an even, consistent surface and finish. It transforms the initial raw tile into a high quality product ready for glazing, packaging and installation.

Quality Control

Quality control is a critical step in tile manufacturing to ensure the tiles meet specifications and are free of defects before being packaged and shipped to customers. Here are the key aspects of tile quality control:

Inspecting for Defects

Finished tiles are visually inspected at the end of the production line. Trained inspectors examine the tiles for any cracks, chips, uneven glazing, color inconsistencies, and other defects that could impact performance or aesthetics. Tiles are checked to ensure they meet the proper size and thickness specifications. Any tiles that do not pass inspection are removed and recycled.

Testing Properties

In addition to visual inspection, tile manufacturers conduct physical tests to ensure the tiles meet durability and performance standards. These include tests for water absorption, breaking strength, resistance to chemicals, staining, and abrasion. Sample tiles may be subjected to freeze/thaw cycling, load testing, and other simulations to verify they will hold up well under real-world conditions. Acceptable tolerance levels are set for each metric.

Packaging and Storage

After the tiles have been polished, grinded, and inspected for quality control, they are ready for packaging and storage. Proper packaging and storage helps ensure the tiles arrive at their destination undamaged and ready for installation.

Individual tiles are first carefully wrapped in paper or thin cardboard. This prevents scratches and chips during transport. The wrapped tiles are then placed in cardboard boxes or on wooden pallets.

For boxed tiles, spacer boards are placed between each layer to prevent rubbing and breakage. The boxes are then sealed and stacked on pallets for storage and shipping. Each pallet typically holds between 1,000 to 2,000 tiles.

For larger format tiles placed directly on pallets, a securing plastic cover is used to unitize the load. This keeps the tile stacks stable and protected during transport. The pallets are then moved to climate-controlled warehouse storage.

In the warehouse, pallets are placed on wide shelves or racking systems. This provides air circulation and easy access for order picking. To prevent damage, pallets should not be stacked more than three high. Most tiles are fragile, so care must be taken when moving pallets.

Tile packaging serves the important role of protecting the final product during storage and delivery to customer locations. With proper wrapping, boxing, palletizing and warehouse storage methods, tiles can arrive in perfect shape, ready for installation.

Distribution and Shipping

Once the tiles are packaged and stored, they need to be distributed to customers and job sites. The main method for shipping tiles is by truck. Tiles are heavy and fragile, so they require specialized shipping.

Tiles are loaded onto pallets and then loaded into the back of tractor trailers using forklifts. The pallets are secured so they don’t shift during transport. Full truckloads are preferred to maximize efficiency and minimize costs. Less than truckload shipping is sometimes required for smaller orders.

Tile distributors plan delivery routes to minimize mileage and fuel costs. Routes are planned based on the locations of tile manufacturing plants, distribution warehouses, and customer delivery addresses. Software helps optimize delivery routes.

Truck drivers must take care in maneuvering and unloading the heavy tile pallets. They use pallet jacks and lift gates to move pallets on and off trucks. Drivers ensure tiles are delivered on time and without any damage.

For overseas shipments, tiles are transported in shipping containers on boats, trains or planes. The containers are specially designed to keep the tiles protected during international transport.

Installation

Proper installation is key to ensuring tiles last a long time. The substrate or surface that tiles will be installed on needs to be properly prepared first. The surface should be clean, dry, structurally sound and flat. Any bumps or uneven spots on the substrate can cause tiles to crack or become unlevel.

For floor tile installation, a cement backer board is often laid over the subfloor to create a perfectly smooth and stiff surface to adhere tiles to. A cleavage membrane may also be applied between the tile and substrate to allow for slight movements.

When it comes to laying the tiles, use a notched trowel to spread a thinset mortar adhesive on the substrate, then press tiles into the mortar. Use spacers between tiles to get consistent grout lines. Tiles may need to be cut to fit around outlets, edges and corners. Allow the thinset to cure fully before grouting.

Grout is then pushed down into the grout lines to fill gaps and create a finished look. Excess grout sitting on top of tiles can be wiped away with a damp sponge. Allow grout lines to cure fully before using the tiled surface.