Plumbing supply chain Heat Merchants is to invest €4m in its branch network, creating 75 jobs over the next three years.
The company also operates Tubs and Tiles and plans to open 13 new branches across the two brands.
Both brands were acquired by Harleston in 2012, following the liquidation of their previous owner BHT Group.
This investment will increase Heat Merchant Group's branch network to 56 throughout the country and will bring the total workforce to 358.
The company said it is also increasing its central distribution and business support centre in Athlone, with the addition of an extra 20,000 sq ft of warehousing, which will extend its capacity to service its expanded branch network.
Recruitment for the new roles, which will be for a variety of areas across the business, will begin immediately.