James Burrell’s new branch opens in Morpeth, on Coopies Lane Industrial Estate, in July following a £1m investment.
The store will offer building and timber products as well as landscaping and roofing supplies.
The company’s other branches are in Blyth, Newcastle, Gateshead, Sunderland, Bishop Auckland, Stockton, York and Ossett.
James Burrell celebrated its 140th anniversary in 2017 and turnover reached £60m last year.
Joint managing director Stephen Richardson said: "We’re proud of our long heritage in the region and we’re looking forward to giving the local builders and tradesmen an improved service through this new location.
“The new depot will also allow us to improve the service to our existing contract customers in Morpeth, Alnwick and surrounding areas of Northumberland.”