The West Midlands headquartered business is reported to have fetched £140m and leaves Interserve to concentrate on its rebranded Tilbury Douglas Construction business.
RMD Kwikform employs over 1,300 people across core markets of the UK, India, Australia and the UAE.
Altrad Group was founded in 1985 by its President Mohed Altrad and has revenues of around €3bn.
It is one of the world’s leading industrial services companies focusing on oil and gas, energy, process and construction markets, employing around 38,000 people.
Alan Lovell, chairman of Interserve Group said: “The sale of RMDK to Altrad Group continues the significant progress we have made selling the constituent parts of Interserve Group to best realise value for our shareholders.
“I have no doubt that RMDK will thrive as part of Altrad Group which will benefit both its staff and clients alike.”
Altrad Group will support RMDK’s growth strategy built on further investment into products, services and geographic expansion.
Ran Oren, joint Chief Executive of Altrad Group said: “We are so excited to welcome RMDK to the Altrad family.
“We have watched and admired RMDK’s specialist engineering skills and services for many years and strongly believe in its brand, client solutions and ability to return to growth.”