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What is really under the cloth? Part 1

The Geological Foundation – Everything about Slate and Leveling
December 29, 2025 by
GePe-Biljarts
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When someone sees a billiard ball glide over a table, they rarely stop to think about the hundreds of kilos of natural stone that lie just beneath the cloth. Yet, the slate is the most important component of the table. Without a perfect, stable foundation, even the most expensive cloth is worthless. In this first part of our series, we explain why slate is the gold standard and how we level that enormous mass with utmost precision to the millimeter.

Why Slate?

In the early years of billiards, there was experimentation with wood, concrete, or even marble, but slate quickly proved to be superior. It is a metamorphic rock that is mined in layers, making it ideal for being ground into a perfectly flat slab.

Slate has two unique properties for the billiards sport:

  1.  Inertia: Due to its enormous weight, the table is insensitive to vibrations. When a ball hits the cushion hard, the foundation remains immovable.
  2. Thermal stability: Although slate is porous and can absorb moisture from the environment (which we solve with heating), the material hardly deforms due to temperature differences.

The Thickness: Mass is Quality

Not all slate is the same. The thickness determines the stability and playing comfort. At GePe-Billiards, we often see that customers are surprised by the weight; a full slate slab for a snooker table can weigh up to 1000 kg.

Discipline

Standard thickness of slate

Function

Pool table

20 mm to 30 mm

Sufficient for recreational play, easier to transport.

Carom & Golf Billiards

40 mm

The standard for competition; provides the necessary mass for a pure ball roll.

Snooker

50 mm

Necessary to support the large span of the table without sagging.


Where does our slate come from?

The foundation of every quality billiard table is slate. Although slate is found in many places around the world, the best quality for billiard tables is usually mined in specific regions of Italy (mainly Liguria) and Brazil.

  • Italy: For decades, Italian slate has been known as the gold standard. The stone from the region around Genoa is relatively soft, allowing it to be ground and polished with extreme precision to create a perfectly flat surface.
  • Brazil: Today, a very large portion of global production comes from Brazil. Brazilian slate is generally slightly harder and very durable, making it extremely suitable for transport and intensive use.

Mining takes place in deep quarries where huge blocks are sawed or split from the rock face. These raw blocks are then cut into slabs and ground to a fraction of a millimeter precision using computer-controlled machines (CNC). Only the purest slabs, free of calcite inclusions or cracks, ultimately make their way to your billiard table.

The rise of Chinese slate

In addition to traditional European and South American sources,Chinahas become one of the largest producers of slate for billiard tables in recent decades. Chinese slate is mined on a large scale and is known for its excellent price-quality ratio.

Although the hardness can vary depending on the specific quarry, the Chinese industry has invested heavily in high-quality grinding technologies. As a result, they can supply slabs that are very consistent in thickness and flatness. For many modern pool tables, Chinese slate has now become the standard, as it provides a reliable and stable playing surface that meets the demands of both recreational players and professionals.

The Art of Leveling: The Battle Against "Drooping"

The most common problem with billiard tables is that the ball "drops": it rolls at the end of its path in a slight curve to the left or right. This almost always indicates a table that is not perfectly level.

Leveling is a time-consuming task that we perform with an extremely sensitive precision level. The process requires a lot of expertise and patience. Especially with tables that have multiple slates or more than 4 legs, any action can affect the overall balance.

Sealing seams: Beeswax vs. Filler

For larger tables, the slate often consists of three parts to facilitate transport. The transitions between these slabs must be imperceptible to the ball. Even a height difference of a fraction of a millimeter can cause a ball to bounce.

We traditionally used beeswax for this. The great advantage is that it can be made liquid with a hot iron and flows into the seam. After hardening, we cut away the excess wax with a razor-sharp knife for a seamless result. Modern alternatives like Bondo (auto body filler) are used for permanent repairs because, unlike beeswax, it hardens chemically and cannot be made liquid again afterward. Especially when the table is heated or direct sunlight hits the table, this provides a more reliable alternative.

What we only see after stripping

It is no secret that we only know the true condition of the slate once the old cloth is removed. Sometimes hidden defects come to light, such as cracks in the stone or holes from careless use. Fortunately, such imperfections can be professionally filled and polished, so the playing quality is like new again.

In the next part of this series, we will look at the cushions: why they can go "dead" and what impact that has on your game.

Heeft u het gevoel dat uw tafel niet meer recht staat? GePe-Biljarts komt graag langs voor een professionele meting en afstelling.**    Get in touch


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GePe-Biljarts December 29, 2025
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