Home Depot’s trade distribution subsidiary SRS Distribution has reached an agreement to buy building-products distributor GMS for $110 a share in a deal totaling $5.5 billion, the companies announced Monday.

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.