Arex GmbH is a manufacturer of special materials for the building trade with its place of business in Witten. It is operated as an independent family-owned business by Dieter A. Gundlach, director of the management board, as well as Dr. Jochen Billecke, Werner Denniger and Mark Eslamlooy. In 2005, the Ardex group made a turnover of €475 million with 1,750 staff.