The message came in a document posted to shareholders as part of BPB's formal response to Saint-Gobain, which went direct to investors last month after failing to win the support of the UK company's board.
BPB runs 90 factories worldwide and sells products such as insulation and ceiling tiles in more than 50 countries. The company's UK operations include British Gypsum Isover, a wall and ceiling plaster joint venture with Saint-Gobain.
The French company acquired ownership of Jewson and fellow builders merchant Graham in a £1.04 billion deal with Meyer International in 2000. Jewson operates more than 440 branches nationwide.
In the document today, BPB said it strongly believed that the offer failed to reflect its 'exceptional growth prospects'.
Chairman Sir Ian Gibson added: 'Today BPB is a very different company from that of five years ago. Under the current management team, BPB has sharpened its strategic focus on its core plasterboard and building plasters business.'
'Through its North American and emerging markets investments and building on its leadership positions in Europe, BPB has established itself as number one in the world for plasterboard and building plasters.'