The work is part of a wider £200m investment programme to bring the council’s housing stock up to Welsh Quality Housing Standards.
Keepmoat has secured the largest of the housing upgrade deals, worth £27m covering the lot known as the Eastern Valley.
It will be refurbishing kitchens and bathrooms and providing new wiring and heating for thousands of homes across the borough over a six-year contract period.
Vinci Facilities will upgrade almost 10,000 homes across the Upper Rhymney Valley under a £15m deal.
Park Port Talbot-based Contract Services (South Wales) has also picked up a £15m improvement programme worth£15m covering Lower Rhymney Valley.