Why are cracks developing in Cava porcelain bathroom sink (installed 4 years ago). We spotted a hairline crack shortly after installation and assumed it might have resulted from a workman indadvertently dropping a tool. But now there are several, more visible, cracks over the surface of the sink. We are very careful not to put any metal objects in ther sink. What could be the cause, and what if anything can we do to repair the sink?

"Cava" or "Lacava"? Did you purchase through an authorized dealer? The sink can't be repaired and needs to be replaced, there might be a warranty on it.

From Lacava - "Please be aware that Lacava LLC is not affiliated with any retail web sites selling Lacava products online. All retail stores whether online or physical entities are independent companies governed by their own policies and ethical conduct. They may be selling second-hand or forged products as original Lacava products. Furthermore, orders you place with those independent companies may never be communicated to Lacava LLC or may be communicated with gross delays. Unprofessional conduct of some retail stores may not only be defamatory to Lacava name, but it may also void your warranty if your purchase cannot be traced with sales receipts and lacava invoice reference as legitimate Lacava merchandise. Service under Lacava warranty is only available for genuine Lacava products purchased through authorized dealers or Lacava web site."