Home Depot said on Monday unit SRS Distribution has agreed to acquire specialty building products distributor GMS for about $4.3 billion, stepping up its efforts to capture more demand from professional contractors.

Home Depot bought SRS Distribution — the subsidiary that’s acquiring GMS — last year for $18.25 billion, in the largest acquisition in its history. Texas-based SRS sells supplies to professionals in the landscaping, roofing and pool businesses and it has bought up many other smaller suppliers as it’s grown.

Home Depot is buying specialty building products distributor GMS Inc. in a deal valued at approximately $4.3 billion