LBS said the purchase of Pembroke Dock-based Talbot would enable it to offer an improved service on trusses and Posi-joist engineered floors, as well as an increased range of softwood, hardwood, fencing and plywood across its entire branch network.
Talbot was established in 1981 and is also a timber merchant.
LBS has 15 merchant branches across South & West Wales and is celebrating its 85th anniversary.