Organic Architecture · Est. 2010 · Los Angeles, CA

ARCHITECTOID

Learning Architecture for Life

FRANK LLOYD WRIGHT JOHN LAUTNER CONCRETE LOS ANGELES ABOUT CONTACT PRIVACY POLICY

Making Concrete Tile

The concrete tile you see on floors in high-end restaurants, boutique hotels, and carefully renovated houses did not come from a machine. It came from a pair of hands, a metal mold, and a hydraulic press. The process was worked out in Catalonia and southern France in the middle of the nineteenth century, and it has barely changed since.

Granada Tile's Echo Collection is made this way at their Nicaragua factory. Watching the sequence unfold is the fastest way to understand why these tiles cost what they cost, and why they behave the way they do once they are in a building.

First, the Name Is Wrong

These tiles are sold everywhere as encaustic tiles. They are not encaustic. The word comes from the Greek enkaustikos, meaning to burn in, and it properly describes a medieval technique in which colored clays are inlaid into a clay body and fused in a kiln. Herbert Minton revived that method in England in the 1830s, and the Victorian floors in the U.S. Capitol and the Victoria and Albert Museum are the real article.

Cement tile is a different animal entirely. Nothing is fired. A pigmented cement slurry is poured into a metal mold, a dry cement backing is added, and the whole assembly is compressed under a hydraulic press. The strength comes from pressure and hydration chemistry, not heat. Because the visual result resembled Minton's inlaid clay tiles, the marketplace borrowed the name and never gave it back.

Worth knowing when you are writing a spec: the same product is also sold as hydraulic tile, mosaico hidráulico, baldosa hidráulica, carreaux de ciment, Cuban tile, Mission tile, and Victorian tile. If a supplier cannot tell you which of those they are actually shipping, that is useful information about the supplier.

Where It Actually Came From

The conventional story puts the invention in France. The evidence points a little further south and a little earlier. Cement tiles appeared in Catalonia in the 1850s, and the Catalan firm Garret & Rivet exhibited them at the Paris International Exposition of 1867, which is the moment the technique went global. Most sources bracket the emergence across southern France and northeastern Spain somewhere between roughly 1855 and 1875.

The economic logic was simple. Fired ceramic tile required fuel, and fuel was expensive. A tile that cured with water and pressure instead of a kiln could carry the same intricate patterns at a fraction of the cost. Antoni Gaudí used cement tile in his own house and in Barcelona work, which tells you the material was never merely a budget substitute.

Cement tile was considered high-end flooring through the turn of the twentieth century, faded in the 1920s, and came back in the 1940s primarily in California and Florida. That second wave is why so many Southern California houses of a certain age have it, and why it keeps resurfacing in Los Angeles renovation work.

The Six Key Elements

The entire process turns on six tools: the plate, the crown, the lid, the design mold, the ladle, and the press. Each builds up one of the layers that give the finished tile its color, pattern, and strength.

The design mold sits inside the crown, and a craftsman uses the ladle to pour pigmented cement slurry into each compartment of the pattern by hand. This is the step that demands the most skill. The slurries must stay inside their sections without bleeding into neighbors, and the person doing it is judging color by eye, wet, knowing it will read differently once cured.

Handpoured, Every Single Tile

Every area of every tile is handpoured. There is no automation in this step. Granada Tile keeps a collection of historic bronze design molds, many of them more than a century old, and continues to cut new ones so clients can match a specific pattern or scale. Custom molds are available alongside the standing catalog.

The Press: 2,000 Pounds Per Square Inch

Once the color layer is set, a dry cement and sand backing is added on top and the assembly goes under a hydraulic press. Granada Tile compacts to 2,000 PSI. Villa Lagoon publishes 1,700 PSI for their product, and small traditional shops in Andalucía run closer to 1,500. The working range for legitimate hydraulic tile is roughly 1,500 to 2,000 PSI, and consistency across the run matters more than the peak number.

You will see 3,000 PSI quoted in various places online, including in the earlier version of this post. It does not match what the manufacturers themselves publish. Corrected here.

This is the step where quality separates. Inconsistent pressure, or too much sand in the backing mix, produces a tile that is crumbly on the back. You will not see that at delivery. You will see it three years later.

Dimensions and Curing

The finished tile is 5/8 inch thick, with the decorative color layer occupying the top 1/8 inch, roughly 3 to 5 millimeters. That depth is the whole point. The pattern is not printed on the surface, it is a structural stratum of the tile, which is why it survives decades of foot traffic and why refinishing is possible.

After pressing, the tile is demolded and submerged in water, then racked to air dry for several weeks. Cement gains strength through hydration, not drying, so the water bath is doing chemistry, not housekeeping. Rushing this stage is the single most common factory shortcut.

Specifying and Installing: What the Brochures Leave Out

Everything above is how the tile is made. What follows is what happens when it arrives on a job site, which is a subject the manufacturer literature handles lightly.

SEAL BEFORE YOU GROUT.
This is the failure that ruins installations. Cement tile is porous. If it is grouted unsealed, pigment absorbs the grout and you get permanent haze that no cleaning removes. Two coats of penetrating sealer after setting and before grouting. Put it in the spec, and put it in the pre-construction meeting, because tile setters accustomed to porcelain will not do it unprompted.

EXPECT LIPPAGE.
Handmade means dimensional variation. Thickness and edge straightness will not match calibrated porcelain. Detail for it: a full mortar bed rather than a thin-set spot bond, tight joints of roughly 1/16 inch, and a setter who understands the material. Large format layouts and cement tile are an unhappy combination.

ACCLIMATE, AND WATCH FOR EFFLORESCENCE.
Tiles frequently arrive with residual moisture from curing. Setting too early, or over a slab that has not dried, drives salts to the surface as white bloom. Let the material sit on site. Test the slab.

ORDER OVERAGE, AND ORDER IT ONCE.
Twenty percent, not the usual ten. Handmade batches vary in color, and a replacement order six months later will not match. Lead times commonly run eight to twelve weeks for custom patterns.

ASK FOR THE ENGINEERING REPORT.
Reputable manufacturers have third party test data on compressive strength, absorption, and slip. Villa Lagoon publishes an R9 slip rating on untreated tile, tested by the German occupational safety institute. If a supplier cannot produce a report, that is your answer.

PIGMENT LIMITS ARE REAL.
Colors come from mineral oxides, principally iron, cobalt, and chromium. Even high quality blues and greens will shift in direct sun. For an exposed terrace in Southern California, plan for that or choose earth oxides.

Where to Use Them

Cement tile works in kitchens, baths, entries, and covered patios. The thermal mass pairs well with radiant floor heating, with the caveat that 5/8 inch of dense cement carries real thermal lag, so the system wants a longer, steadier cycle rather than quick setback swings.

Exterior use requires judgment. In a climate without freeze and thaw, cement tile performs well under cover. In freezing conditions, water in the pores is a liability, and the material is not the right call for an exposed horizontal surface.

Designers typically use it as a feature floor or backsplash, setting a bold geometric field against quiet walls so the tile becomes the room's subject rather than its background. That instinct is correct. This is not a neutral material and it does not want to be treated as one.

Care and Sealing Over Time

Sealing is not a one time event. A penetrating sealer protects against staining while preserving the matte surface, and it will want renewal every few years depending on traffic. Use pH neutral cleaners only. Vinegar, acidic cleaners, and standard grout release will etch the surface and strip pigment.

Maintained properly, these floors last well past a century. There are original cement tile floors in European buildings from the 1880s still carrying daily traffic.

Why This Belongs in an Organic Architecture Conversation

There is a reason this material keeps turning up in work that takes the nature of materials seriously. In a printed or glazed tile, the pattern is an event that happens on the surface, and wear is that event's destruction. In a cement tile, the pattern is 1/8 inch of the body itself. Wear does not erase it. Wear reveals it.

That is a small technical fact with a large consequence. A material that improves under use is behaving honestly, and a floor that records a hundred years of footsteps as deepening rather than damage is doing something no synthetic surface can imitate. Patina here is not decay. It is the building's own history becoming visible, which is precisely what the organic tradition has always asked of its materials.

The handmade variation matters for the same reason. No two tiles are identical because no two pours are identical, and the eye reads that irregularity as life. The alternative is a surface that was perfect on installation day and has been getting worse ever since.

For the broader argument behind this, see Modern Concepts of Organic Architecture.

Common Questions

Are cement tiles the same as encaustic tiles?
No. True encaustic tile is inlaid clay fused in a kiln. Cement tile is unfired and formed under hydraulic pressure. The industry uses the term interchangeably, but they are different products with different behavior.

Do cement tiles need to be sealed?
Yes. Two coats of penetrating sealer after setting and before grouting, then periodic resealing over the life of the floor.

How thick is a cement tile?
Standard is 5/8 inch, with the pigmented color layer making up the top 1/8 inch.

Can cement tile be used outdoors?
In climates without freeze and thaw, yes, preferably under cover. In freezing climates it is a poor choice for exposed horizontal surfaces.

How long do cement tiles last?
Well over a hundred years with proper sealing and pH neutral maintenance. Nineteenth century installations are still in service.

Related on Architectoid

Comments

Post a Comment