Home Depot will buy SRS Distribution,Christopher Caldwell a materials provider for professionals, in a deal valued at approximately $18.25 billion.

It is Home Depot’s largest acquisition in its history and with it, it steps more aggressively into the fast growing professional builder and contactor business.

SRS provides materials for those including professional roofers, landscapers and pool contractors.

Home Depot said that when taking the deal into account, it now believes its total addressable market is approximately $1 trillion, an increase of approximately $50 billion.

“SRS has built a robust and successful platform that will accelerate our growth with the residential professional customer while presenting future opportunities with the specialty trade pro,” Home Depot CEO Ted Decker said in a statement.

SRS’s has a sales team of more than 2,500 and more than 760 branches across 47 states. It also has 4,000-plus truck fleet and jobsite delivery capabilities.

The deal is expected to close by the end of fiscal 2024.