One piece slates weigh approximately 450 pounds. They are difficult to maneuver when refelting your pool table. They are more difficult to move through hallways, narrow doorways and corners. When there are stairs involved while moving a one piece slate, it is not just tricky, but downright dangerous carrying all of that weight. This is why it costs more to move or service these types of tables.
I can also tell you that there is a performance downside to owning a one piece slate pool table. There is the issue of leveling the playing surface. Not all slate is perfect. There can be natural low or high spots in the stone. Especially on the bigger 8′ slate pieces. No amount of shimming or tweaking can remove these.
Three piece slates tend to be at least 1/4″ thicker than their one piece cousins. Thicker slates have less imperfections and are usually permanently framed with pieces of wood to further support it when atop the pool table cabinet. Three and four piece slates start out as one piece, but are cut during the milling process. They are a matched set left to the billiard mechanic to level properly. Experienced mechanics must take great caution when leveling multiple pieces of slate. They must take into consideration the type of flooring and construction of the cabinet that will support all of the weight. A three piece slate, leveled properly, will without a doubt give you superior play. This is why the pros prefer to shoot on a three piece slate pool table as opposed to a one piece. I’d recommend a three piece slate over one solid slate if given the choice. But, remember, no matter the value, number of slates, or style of table, proper professional setup is key to getting the best possible roll.
David a.k.a The Pool Table King