Offer Update

Compagnie de Saint-Gobain
09 November 2005

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



9 November 2005



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

                         Cash Offer for BPB plc ('BPB')

                       Clearance from European Commission

                       BPB is exaggerating its prospects
              Saint-Gobain's Offer represents full and fair value

Saint-Gobain is pleased to note that the European Commission has cleared its
proposed acquisition of BPB.  As a result, the Offer timetable has restarted.
Day 39 of the Offer timetable, which is the last day on which BPB can announce
material new information, will be Friday 11 November 2005.  Except with the
consent of the Panel, the last date on which the Offer can become or be declared
unconditional as to acceptances will be Friday 2 December 2005.

Saint-Gobain will today post a document to BPB Shareholders that rejects BPB's
exaggerated claims that Saint-Gobain's offer is inadequate.  The document sets
out why Saint-Gobain continues to believe its Offer represents full and fair
value for BPB.

The following is the text of the letter from the Chairman and Chief Executive of
Saint-Gobain, which is set out in the document:

'Dear Shareholder,

As you will be aware, Saint-Gobain has made an offer to acquire BPB for 720p per
share in cash. We believe this offer represents full and fair value and allows
you to realise a substantial premium for your shares now.

We have sought, on a number of occasions, to discuss our offer with BPB.
Unfortunately, BPB has refused to negotiate with us and has instead chosen to
argue the merits of our offer in public. Over the last two months, BPB has made
a number of exaggerated claims to substantiate its argument that our offer is
inadequate. In doing so, BPB has used questionable data to support its arguments
and we believe has committed the company to a strategy that puts the company's
growth prospects at real risk.

Now that the bid timetable has restarted, we feel it is appropriate to write to
you to set out why we believe BPB's defence claims are exaggerated and in some
cases are simply without substance.

Claim 1: 720p 'massively' undervalues BPB

To claim our offer 'massively' undervalues BPB is patently not true. Our offer
represents a very substantial premium of 40.5 per cent. to the BPB share price
before we made our approach. It also offers a premium valuation when compared to
recent transactions in the sector.

BPB has stated that we should be offering a superior multiple to the price paid
by Holcim for Aggregate Industries. We are. Whether looked at from a price
earnings multiple, or using the industry's preferred benchmark of enterprise
value multiples, our offer is superior.

Claim 2: BPB should be rated at a premium to its European peers

BPB is trying to argue that it deserves a re-rating and that this re-rating by
the market will enable it to trade, in the absence of our offer, at a higher
share price than before we made our approach. The question is - what has
changed? Why should BPB suddenly be trading on higher multiples when it has
traded in line with its European peers for ten years? BPB does not help its case
by trying to align itself with an international, rather than European, peer
group in an attempt to be rated as a US stock.

The fact is, BPB is fundamentally a European business and there is nothing to
suggest it should trade other than in line with its European peers. On this
basis, BPB's trading range would be around 565p, which is still well above the
level it traded at before our approach.

Claim 3: Financial engineering creates value

BPB has also tried to claim it can create value by returning cash to
shareholders and hiking the dividends by 88 per cent. But the facts do not
support this. Empirical evidence from recent share buybacks shows that financial
engineering simply does not create value.

Claim 4: Financial engineering will not affect BPB's ability to grow

BPB's ambitious growth 'targets' will not only require that all of its plans
work out successfully, it will also require very substantial capital investment.
Can BPB really claim that its financial engineering defence will not impact its
ability to grow? Following BPB's proposed cash return to shareholders, it will
be the most heavily indebted company in its sector, with gearing of over 300 per
cent. We believe that BPB's ability to grow must be affected by such heavy
borrowing.

With BPB facing heavy capital investment to achieve its growth 'targets', is now
really the time to be mortgaging the future of the company in an effort to
persuade you to decline our offer?

Claim 5: BPB can achieve double-digit growth

BPB has stated that it is 'targeting' double-digit earnings per share growth,
but has not made this 'target' a formal profit forecast. There are considerable
risks that this 'target' will be missed, not least due to the cyclical nature of
the business.

BPB's strong growth in recent years has been driven by acquisitions and by
favourable market conditions in the US. But this will not drive future growth -
even BPB has admitted that the US will not grow at the same rate as in the last
few years.

BPB's future growth is therefore significantly reliant on emerging markets in
Europe and Asia. However, achieving emerging market growth is more challenging
than in developed countries. Our experience shows that emerging market growth
requires proportionately more capital investment to achieve incremental sales.
And this will be exacerbated by the fact that BPB's emerging market business is
small and is starting from a weak position compared with its competitors, which
will place pressure on margins.

This document addresses each of BPB's claims in detail and sets out our
arguments as to why we are convinced BPB has exaggerated its prospects in an
effort to persuade you to reject our offer. Our offer represents excellent value
for shareholders and offers certainty of value now. I strongly urge you to
accept our offer as soon as possible and in any event by no later than 13
November 2005.

Yours faithfully

Jean-Louis Beffa

Chairman & CEO'

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, including information included or incorporated by reference
in this announcement, contains 'forward-looking statements' concerning
Saint-Gobain and BPB.  Information in this announcement relating to BPB has been
compiled from published sources.  Generally, the words 'will', 'may', 'should',
'continue', 'believes', 'expects', 'intends', 'anticipates' or similar
expressions identify forward-looking statements.  These forward-looking
statements involve risks and uncertainties that could cause actual results to
differ materially from those expressed in the forward-looking statements.  Many
of these risks and uncertainties relate to factors that are beyond the
companies' ability to control or estimate precisely, such as future market
conditions and the behaviour of other market participants.  Although we believe
that the expectations reflected in such forward-looking statements are
reasonable, we can give no assurance that such expectations will prove to have
been correct.  We caution you not to place undue reliance on these
forward-looking statements, which speak only as of the date of this announcement
and, except as otherwise required by law, Saint-Gobain does not undertake to
update any of the forward-looking statements set out 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.


APPENDIX: Sources and bases of information

Unless otherwise stated, financial and other information relating to the BPB
Group is derived from BPB's circular to BPB Shareholders dated 14 September 2005
(the 'First Defence Document'), BPB's circular to BPB Shareholders dated 3
November 2005 (the 'Second Defence Document'), the Annual Report, other
published annual reports and accounts of BPB for the relevant periods and other
information made publicly available by the BPB Group.

Unless otherwise stated, reference to BPB's European peer group comprises
Saint-Gobain, CRH plc, Hanson plc, HeidelbergCement AG, Holcim Ltd, Italcementi
SpA, Kingspan Group plc, Lafarge SA, Pilkington plc, Societe Ciments Francais SA
and Wienerberger AG.

P/E multiples are calculated by dividing the share price by the earnings per
share.

The reference to BPB's claim that Saint-Gobain's offer 'massively' undervaluing
BPB is sourced from a quote in the Financial Times (UK edition) of 15 September
2005.

The reference to the Offer representing a premium of 40.5% is based on
Saint-Gobain's offer of 720p per share and BPB's share price of 512.5p on 20
July 2005, the last trading day prior to commencement of the Offer Period.

The reference to a premium valuation when compared to recent transactions in the
sector relates to Cemex's acquisition of RMC and Holcim's acquisition of
Aggregate Industries, which are compared in the Offer Document.

The reference to BPB stating that Saint-Gobain should be offering a superior
multiple to the price paid by Holcim for Aggregate Industries is sourced from
page ten of the Second Defence Document.

The reference to BPB's claim that it deserves a re-rating and that this
re-rating by the market will enable it to trade, in the absence of our offer, at
a higher share price than before we made our approach is based on the 715p
implied trading value that BPB attributes to each share on page 21 of the First
Defence Document.

The reference to BPB having traded in line with its European peers for the last
ten years is based on the average one-year forward P/E multiple over the 10
years to 20 July 2005, the last day prior to commencement of the Offer Period,
for BPB of 11.7x for BPB's European peer group of 12.0x, both sourced from
Datastream.

The reference to BPB suggesting that its shares should be rated in line with an
international peer group that includes highly-rated US stocks is based on page
20 of the First Defence Document which states that BPB should trade at a premium
to the current year average P/E multiple for its peer group, which includes US
stocks.

The reference to BPB's shares being likely to trade at around 565p is based on a
diluted EPS for BPB for the year ending 30 March 2006 and a one-year forward P/E
multiple based on BPB's European peer group of 12.0x, calculated as follows:

(a) the diluted EPS for BPB of 47p is calculated based on a pre-return of
capital underlying earnings of £240 million and pre-return of capital diluted
number of shares of 508 million, sourced from page 26 and 25 of the First
Defence Document, respectively.

(b) the one-year forward P/E multiple of 12.0x is the average of the one-year
forward P/E multiples of BPB's European peer group, based on consensus analyst
estimates for EPS sourced from Reuters as at 7 November 2005 and closing share
prices sourced from Datastream as at 7 November 2005 for each company.
HeidelbergCement AG has been excluded from BPB's European peer group following
the announcement by Spohn Cement GmbH on 10 June 2005 of its intention to submit
an offer to the shareholders of HeidelbergCement AG. Pilkington plc has been
excluded from BPB's European peer group following the announcement by Nippon
Sheet Glass Company Limited on 31 October that it has made an approach to the
board of Pilkington plc which may or may not lead to a cash offer for the
Pilkington plc shares it does not already own.

The increase in dividend payments of 88% over the next three years is sourced
from page one of the Second Defence Document.

The reference to BPB (following its proposed cash return to shareholders) being
the most heavily borrowed company in its sector, with gearing of over 300% is
calculated by dividing net debt of £422 million as at 31 March 2005 adjusted for
the £600 million cash return to shareholders by shareholders' funds of £936
million as at 31 March 2005 adjusted for the cash return to shareholders.

The reference to BPB stating that it is 'targeting' double-digit earning per
share growth is sourced from page one of the Second Defence Document.

The reference to BPB admitting that the US will not grow at the same rate as in
the last few years is based on underlying operating profit/(loss) from North
America resulting in a profit in 2005 compared to a loss in 2002, as sourced
from page 14 of the First Defence Document, compared to future market growth
expectations of 3-4% per annum as sourced from page 15 of the First Defence
Document.

The reference to BPB's weak position in emerging markets compared with its
competitors is explained on page eleven of Saint-Gobain circular posted to BPB
shareholders today.


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