Offer Document Posted

Compagnie de Saint-Gobain
31 August 2005


Not for release, publication or distribution, in whole or in part, in, into or
from Australia, Canada or Japan


                                                              31 August 2005


                   Compagnie de Saint-Gobain ('Saint-Gobain')

                 Posting of Offer Document to BPB Shareholders

Saint-Gobain announces that the Offer Document containing the cash offer for BPB
made outside the United States by BNP Paribas and UBS Investment Bank on behalf
of Saint-Gobain Aldwych Limited (the 'Offeror'), a wholly owned subsidiary of
Saint-Gobain, and in the United States by the Offeror itself, is being posted to
BPB Shareholders today.

Acceptances to the Offer should be received as soon as possible following
receipt of the Offer Document and in any event, by no later than 1.00pm  (London
Time) on 30th September 2005.

The Offer of 720 pence in cash per BPB Share represents:

       A significant premium to BPB's historic share price

       A significant premium to recent market earnings multiples

       A premium valuation in comparison to other recent transactions in the
       sector

Saint-Gobain's Offer provides BPB Shareholders with the opportunity to realise a
premium valuation in cash now.

Saint-Gobain believes that 720 pence represents a full and fair price for BPB
Shareholders.  It represents a 40.5% premium to BPB's closing price on 20th
July, the last day prior to the Offer Period.  This Offer is an excellent
opportunity for BPB Shareholders to realise a cash exit from their investment
now.  Saint-Gobain encourages Shareholders to accept its Offer.



Enquiries


Saint-Gobain (for analysts and investors)


Florence Triou-Teixeira, Head of IR                 Tel: [phone]

Alexandre Etuy, Deputy Head of IR                   Tel: [phone]


BNP Paribas (joint financial adviser to Saint-Gobain)


Thierry Dormeuil                                    Tel: [phone]

Oliver Ellingham                                    Tel: [phone]


UBS Investment Bank (joint financial adviser and broker to Saint-Gobain)


Charles-Henri Le Bret                               Tel: [phone]

Liam Beere                                          Tel: [phone]


Brunswick (PR adviser to Saint-Gobain)


John Sunnucks                                       Tel: [phone]

Sophie Fitton                                       Tel: [phone]


Notes

Copies of the Offer Document and the Form of Acceptance are available for
collection (during normal business hours) from Capita Registrars at PO Box 166,
The Registry, 34 Beckenham Road, Beckenham, Kent BR3 4TH.

Further information on Saint-Gobain is available on Saint-Gobain's website
www.saint-gobain.com.

Terms used in this announcement shall have the meaning given to them in the
Offer Document.

The Offer in the United States is made solely by the Offeror and neither BNP
Paribas, UBS nor any of their respective affiliates is making the Offer into the
United States.

The Saint-Gobain Directors and the Offeror Directors accept responsibility for
the information contained in this announcement. To the best of the knowledge and
belief of the Saint-Gobain Directors and the Offeror Directors (who have taken
all reasonable care to ensure that such is the case), the information contained
in this announcement for which they are responsible is in accordance with the
facts and does not omit anything likely to affect the import of such
information.

BNP Paribas and UBS are acting exclusively for Saint-Gobain and the Offeror in
connection with the Offer and no one else, and will not be responsible to anyone
other than Saint-Gobain and the Offeror for providing the protections afforded
to respective clients of BNP Paribas and UBS nor for providing advice in
relation to the Offer or any other matter referred to herein.

This announcement does not constitute an offer to sell or an invitation to
purchase any securities or the solicitation of an offer to buy any securities.


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