<PAGE>   1

                                                                     EXHIBIT 1.1





                                  $650,000,000

                               LAFARGE CORPORATION

                          ___% Senior Notes due _______

                             UNDERWRITING AGREEMENT



                                                        July ___, 1998


DONALDSON, LUFKIN & JENRETTE
  SECURITIES CORPORATION
WARBURG DILLON READ LLC
CITICORP SECURITIES, INC.
c/o Donaldson, Lufkin & Jenrette Securities Corporation
       277 Park Avenue
       New York, New York 10172

Dear Sirs:

   
         Lafarge Corporation, a Maryland corporation (the "Company"), proposes
to issue and sell $650,000,000 principal amount of its __% Senior Notes due ____
(the "Securities") to Donaldson, Lufkin & Jenrette Securities Corporation,
Warburg Dillon Read LLC and Citicorp Securities, Inc. (the "Underwriters") in
the amounts specified in Schedule I hereto. The Securities are to be issued
pursuant to the provisions of an Indenture dated as of October 1, 1989, as
supplemented by a Supplemental Indenture thereto, to be dated as of _____ ___,
1998 (collectively, the "Indenture") between the Company and Citibank, N.A., as
Trustee (the "Trustee"). Capitalized terms used but not defined herein shall
have the meanings given to such terms in the Indenture.
    

         SECTION 1. Registration Statement and Prospectus. The Company has
prepared and filed with the Securities and Exchange Commission (the
"Commission") in accordance with the provisions of the Securities Act of 1933,
as amended, and the rules and regulations of the Commission thereunder
(collectively, the "Act"), a registration statement on Form S-3 (No. 333-57333),
including a prospectus, relating to the Securities. The registration statement,
as amended at the time it became effective, including the information (if any)





<PAGE>   2

deemed to be part of the registration statement at the time of effectiveness
pursuant to Rule 430A under the Act, is hereinafter referred to as the
"Registration Statement"; and the prospectus in the form first used to confirm
sales of Securities is hereinafter referred to as the "Prospectus". Reference
made herein to any preliminary prospectus or to the Prospectus shall include all
documents incorporated by reference therein as of the date of such preliminary
prospectus or Prospectus, as the case may be, and any reference to any amendment
or supplement to any preliminary prospectus or the Prospectus shall be deemed to
refer to and include any documents filed after such date under the Securities
Exchange Act of 1934, as amended (the "Exchange Act") and incorporated by
reference in such amendment or supplement. If the Company has filed or is
required pursuant to the terms hereof to file a registration statement pursuant
to Rule 462(b) under the Act registering additional Securities (a "Rule 462(b)
Registration Statement"), then, unless otherwise specified, any reference herein
to the term "Registration Statement" shall be deemed to include such Rule 462(b)
Registration Statement.

         SECTION 2. Agreements to Sell and Purchase. On the basis of the
representations and warranties contained in this Agreement, and subject to its
terms and conditions, the Company agrees to issue and sell, and each Underwriter
agrees, severally and not jointly, to purchase from the Company the principal
amount of the Securities set forth opposite the name of such Underwriter in
Schedule I hereto at ____% of the principal amount thereof (the "Purchase
Price").

         SECTION 3. Terms of Public Offering. The Company is advised by you that
the Underwriters propose (i) to make a public offering of their respective
portions of the Securities as soon after the execution and delivery of this
Agreement as in your judgment is advisable and (ii) initially to offer the
Securities upon the terms set forth in the Prospectus.

         SECTION 4. Delivery and Payment. The Securities shall be represented by
definitive certificates and shall be issued in such authorized denominations and
registered in such names as Donaldson, Lufkin & Jenrette Securities Corporation
shall request no later than two business days prior to the Closing Date (as
defined below). The Company shall deliver the Securities, with any transfer
taxes thereon duly paid by the Company, to Donaldson, Lufkin & Jenrette
Securities Corporation through the facilities of The Depository Trust Company
("DTC"), for the respective accounts of the several Underwriters, against
payment to the Company of the Purchase Price therefore by wire transfer of
Federal or other funds immediately available in New York City. The certificates
representing the Securities shall be made available for inspection not later
than 9:30 A.M., New York City time, on the business day prior to the Closing
Date (as defined below), at the office of DTC or its designated custodian (the
"Designated Office"). The time and date of delivery and payment for the
Securities shall be 9:00 A.M., New York City time, on _____ ___, 1998 or such
other time on the same or such other date as Donaldson, Lufkin & Jenrette
Securities Corporation and the Company 


                                       2
<PAGE>   3

shall agree in writing. The time and date of such delivery and payment are
hereinafter referred to as the "Closing Date".

   
         The documents to be delivered on the Closing Date on behalf of the
parties hereto pursuant to Section 8 of this Agreement shall be delivered at the
offices of Milbank, Tweed, Hadley & McCloy, Washington, D.C. and the Securities
shall be delivered at the Designated Office, all on the Closing Date.
    

         SECTION 5.  Agreements of the Company.  The Company agrees with you:

          (a) To advise you promptly and, if requested by you, to confirm such
advice in writing, (i) of any request by the Commission for amendments to the
Registration Statement or amendments or supplements to the Prospectus or for
additional information, (ii) of the issuance by the Commission of any stop order
suspending the effectiveness of the Registration Statement or of the suspension
of qualification of the Securities for offering or sale in any jurisdiction, or
the initiation of any proceeding for such purposes, (iii) when any amendment to
the Registration Statement becomes effective, (iv) if the Company is required to
file a Rule 462(b) Registration Statement after the effectiveness of this
Agreement, when the Rule 462(b) Registration Statement has become effective, (v)
of the happening of any event during the period referred to in Section 5(d)
below which makes any statement of a material fact made in the Registration
Statement or the Prospectus untrue or which requires any additions to or changes
in the Registration Statement or the Prospectus in order to make the statements
therein not misleading and (vi) of receipt by the Company or any representative
or attorney for the Company of any other communication from the Commission
relating to the Company, the Registration Statement or any Prospectus. If at any
time the Commission shall issue any stop order suspending the effectiveness of
the Registration Statement, the Company will use its reasonable best efforts to
obtain the withdrawal or lifting of such order at the earliest possible time.

          (b) To furnish (i) to you four signed copies of the Registration
Statement as first filed with the Commission and of each amendment to it,
including all exhibits, and (ii) to you and each Underwriter designated by you
such number of conformed copies of the Registration Statement as so filed and of
each amendment to it, without exhibits, as you may reasonably request.

          (c) To prepare the Prospectus, the form and substance of which shall
be reasonably satisfactory to you, and to file the Prospectus in such form with
the Commission within the applicable period specified in Rule 424(b) under the
Act; during the period specified in Section 5(d) below, not to file any further
amendment to the Registration Statement and not to make any amendment or
supplement to the Prospectus of which you shall not previously have been advised
or to which you shall reasonably object after being so advised; and, during such
period, to prepare and file with the Commission, promptly upon your reasonable
request, any amendment to the Registration Statement or amendment or supplement
to the Prospectus which may be necessary or advisable in connection



                                       3
<PAGE>   4

with the distribution of the Securities by you, and to use its reasonable best
efforts to cause any such amendment to the Registration Statement to become
promptly effective.

   
          (d) Prior to 12:00 P.M., New York City time, on the first business day
after the date of this Agreement and from time to time thereafter for such
period as in the opinion of counsel for the Underwriters a prospectus is
required by law to be delivered in connection with sales by an Underwriter or a
dealer, to furnish in New York City to each Underwriter and any dealer as many
copies of the Prospectus (and of any amendment or supplement to the Prospectus)
as such Underwriter or dealer may reasonably request.
    

          (e) If during the period specified in Section 5(d), any event shall
occur or condition shall exist as a result of which, in the opinion of counsel
for the Underwriters, it becomes necessary to amend or supplement the Prospectus
in order to make the statements therein, in the light of the circumstances when
the Prospectus is delivered to a purchaser, not misleading, or if, in the
opinion of counsel for the Underwriters, it is necessary to amend or supplement
the Prospectus to comply with applicable law, forthwith to prepare and file with
the Commission an appropriate amendment or supplement to the Prospectus so that
the statements in the Prospectus, as so amended or supplemented, will not in the
light of the circumstances when it is so delivered, be misleading in any
material respect, or so that the Prospectus will comply with applicable law, and
to furnish to each Underwriter and to any dealer such number of copies thereof
as such Underwriter or dealer may reasonably request.

          (f) Prior to any public offering of the Securities, to cooperate with
you and counsel for the Underwriters in connection with the registration or
qualification of the Securities for offer and sale by the several Underwriters
and by dealers under the state securities or Blue Sky laws of such jurisdictions
as you may request, to continue such registration or qualification in effect so
long as required for distribution of the Securities and to file such consents to
service of process or other documents as may be necessary in order to effect
such registration or qualification; provided, however, that the Company shall
not be required in connection therewith to (i) qualify as a foreign corporation
in any jurisdiction in which it is not now so qualified, (ii) take any action
that would subject it to taxation in any jurisdiction or (iii) take any action
that would subject it to general consent to service of process other than as to
matters and transactions relating to the Prospectus, the Registration Statement,
any preliminary prospectus or the offering or sale of the Securities, in any
jurisdiction in which it is not now so subject.

          (g) To make generally available to its security holders as soon as
reasonably practicable an earnings statement, which need not be audited,
covering a period of at least twelve-months after the effective date of the
Registration Statement that shall satisfy the provisions of Section 11(a) of the
Act, and to advise you in writing when such statement has been so made
available.


                                       4
<PAGE>   5


          (h) The Company, during the period when the Prospectus is required to
be delivered under the Act, will file promptly all documents required to be
filed with the Commission pursuant to Sections 13(a), 13(c), 14 or 15(d) of the
Exchange Act.

          (i) So long as the Securities are outstanding, to furnish to you as
soon as available copies of all reports or other communications furnished to its
security holders or furnished to or filed with the Commission or any national
securities exchange on which any class of securities of the Company is listed
and such other publicly available information concerning the Company and its
subsidiaries as you may reasonably request.

   
          (j) Whether or not the transactions contemplated in this Agreement are
consummated or this Agreement is terminated, to pay or cause to be paid all
out-of-pocket expenses reasonably incurred and incident to the performance of
its obligations under this Agreement, including: (i) the reasonable fees,
disbursements and expenses of the Company's counsel and the Company's
accountants in connection with the registration and delivery of the Securities
under the Act and all other reasonable fees and expenses in connection with the
preparation, printing, filing and distribution of the Registration Statement
(including financial statements and exhibits), any preliminary prospectus, the
Prospectus and all amendments and supplements to any of the foregoing, including
the mailing and delivering of copies thereof to the Underwriters and dealers in
the quantities specified herein, (ii) all reasonable costs and expenses related
to the transfer and delivery of the Securities to the Underwriters, including
any transfer or other taxes payable thereon, (iii) all costs of printing or
producing this Agreement and any other agreements or documents in connection
with the offering, purchase, sale or delivery of the Securities, (iv) all
expenses in connection with the registration or qualification of the Securities
for offer and sale under the securities or Blue Sky laws of the several states
and all costs of printing or producing any Preliminary and Supplemental Blue Sky
Memoranda in connection therewith (including the filing fees and fees and
disbursements of counsel for the Underwriters in connection with such
registration or qualification and memoranda relating thereto), (v) any filing
fees and disbursements of counsel for the Underwriters in connection with the
review and clearance of the offering of the Securities by the National
Association of Securities Dealers, Inc., if any, (vi) the cost of printing
certificates representing the Securities, (vii) the costs and charges of any
transfer agent, registrar and/or depositary (including the Depository Trust
Company), (viii) any fees charged by rating agencies for the rating of the
Securities, (ix) the fees and expenses of the Trustee and the Trustee's counsel
in connection with the Indenture and the Securities and (x) all other reasonable
costs and expenses incident to the performance of the obligations of the Company
hereunder for which provision is not otherwise made in this Section.
    

                                       5
<PAGE>   6


          (k) During the period beginning on the date hereof and continuing to
and including the Closing Date, not to offer, sell, contract to sell or
otherwise transfer or dispose of any debt securities of the Company or any
warrants, rights or options to purchase or otherwise acquire debt securities of
the Company substantially similar to the Securities (other than (i) the
Securities and (ii) commercial paper issued in the ordinary course of business),
without the prior written consent of Donaldson, Lufkin & Jenrette Securities
Corporation.

          (l) To use its reasonable best efforts to do and perform all things
required or necessary to be done and performed under this Agreement by the
Company prior to the Closing Date and to satisfy all conditions precedent to the
delivery of the Securities.

          (m) If the Registration Statement at the time of the effectiveness of
this Agreement does not cover all of the Securities, to file a Rule 462(b)
Registration Statement with the Commission registering the Securities not so
covered in compliance with Rule 462(b) by the earlier of 10:00 A.M., New York
City time, on the date after this Agreement and the time confirmations are first
sent or given for the Securities, and to pay to the Commission the filing fee
for such Rule 462(b) Registration Statement at the time of the filing thereof or
to give irrevocable instructions for the payment of such fee pursuant to Rule
111(b) under the Act.

         SECTION 6. Representations and Warranties of the Company. The Company
represents and warrants to each Underwriter that:

           (a) The Registration Statement has become effective (other than any
Rule 462(b) Registration Statement to be filed by the Company after the
effectiveness of this Agreement); any Rule 462(b) Registration Statement filed
after the effectiveness of this Agreement will become effective no later than
the earlier of 10:00 A.M., New York City time, on the date of this Agreement and
the time confirmations are first sent or given for the Securities, and no stop
order suspending the effectiveness of the Registration Statement is in effect,
and no proceedings for such purpose are pending before or threatened by the
Commission.

           (b) (i) The Registration Statement (other than any Rule 462(b)
Registration Statement to be filed by the Company after the effectiveness of
this Agreement), when it became effective, did not contain and, as amended, if
applicable, will not contain any untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading, (ii) the Registration Statement (other than
any Rule 462(b) Registration Statement to be filed by the Company after the
effectiveness of this Agreement) and the Prospectus comply and, as amended or
supplemented, if applicable, will comply in all material respects with the Act,
(iii) if the Company is required to file a Rule 462(b) Registration Statement
after the effectiveness of this Agreement, such Rule 462(b) Registration
Statement and any amendments



                                       6
<PAGE>   7

thereto, when they become effective (A) will not contain any untrue statement of
a material fact or omit to state a material fact required to be stated therein
or necessary to make the statements therein not misleading and (B) will comply
in all material respects with the Act and (iv) the Prospectus does not contain
and, as amended or supplemented, if applicable, will not contain any untrue
statement of a material fact or omit to state a material fact necessary to make
the statements therein, in the light of the circumstances under which they were
made, not misleading, except that the representations and warranties set forth
in this paragraph do not apply to statements or omissions in the Registration
Statement or the Prospectus or any amendment or supplement thereto based upon
information relating to any Underwriter furnished to the Company in writing by
such Underwriter through you expressly for use therein. In addition, the
documents incorporated by reference into the Prospectus, at the time they were
or hereafter are filed with the Commission, complied and will comply in all
material respects with the requirements of the Exchange Act and the rules and
regulations promulgated thereunder, and, when read together and with the other
information in the Prospectus, did not and will not contain an untrue statement
of a material fact or omit to state a material fact required to be stated
therein or necessary in order to make the statements therein, in the light of
the circumstances under which they were or are made, not misleading.

   
          (c) Except for those matters amended or included in the Prospectus,
the preliminary prospectus filed as part of the registration statement as
originally filed or as part of any amendment thereto, or filed pursuant to Rule
424 under the Act, complied when so filed in all material respects with the Act,
and did not contain an untrue statement of a material fact or omit to state a
material fact required to be stated therein or necessary to make the statements
therein, in the light of the circumstances under which they were made, not
misleading, except that the representations and warranties set forth in this
paragraph do not apply to statements or omissions in any preliminary prospectus
based upon information relating to any Underwriter furnished to the Company in
writing by such Underwriter through you expressly for use therein.

          (d) The Company and each subsidiary of the Company listed on Exhibit A
(collectively, the "Subsidiaries"), each of which is a significant subsidiary as
defined in Rule 405 of Regulation C of the rules and regulations of the
Commission under the Act (collectively, the "Subsidiaries") has been duly
incorporated, is validly existing as a corporation in good standing under the
laws of its jurisdiction of incorporation and has the corporate power and
authority to conduct its business as described in the Prospectus and to own,
lease and operate its properties, and each is duly qualified and is in good
standing as a foreign corporation authorized to do business in each jurisdiction
in which the nature of its business or its ownership or leasing of property
requires such qualification, except where the failure to be so qualified or to
be in good standing would not have a material adverse effect on the condition,
financial or otherwise, or the earnings, business affairs or business prospects
of the Company and its subsidiaries considered as one enterprise, and all of the
issued and outstanding capital stock of each Subsidiary has been duly authorized
and validly issued and is fully paid and non-assessable and, except for
directors' qualifying shares and
    



                                       7
<PAGE>   8

the Exchangeable Preference Shares, no par value, of Lafarge Canada, Inc., is
owned by the Company, directly or through subsidiaries, free and clear of any
security interest, mortgage, pledge, lien, encumbrance, claim or equity (each, a
"Lien").

          (e) No labor disturbance by the employees of the Company or any of its
subsidiaries exists or, to the knowledge of the Company, is imminent which might
be expected to materially adversely affect the conduct of the business
operations, financial condition or income of the Company and its subsidiaries
considered as one enterprise.

          (f) The Indenture has been duly qualified under the Trust Indenture
Act of 1939, as amended (the "Trust Indenture Act"), and has been duly
authorized, executed and delivered by the Company and is a valid and binding
agreement of the Company, enforceable in accordance with its terms except as (A)
the enforceability thereof may be limited by bankruptcy, insolvency or similar
laws affecting creditors' rights generally and (B) rights of acceleration and
the availability of equitable remedies may be limited by equitable principles of
general applicability.

          (g) The Securities have been duly authorized and, on the Closing Date,
will have been validly executed and delivered by the Company. When the
Securities have been executed and authenticated in accordance with the
provisions of the Indenture and delivered to and paid for by the Underwriters in
accordance with the terms of this Agreement, the Securities will be entitled to
the benefits of the Indenture and will be valid and binding obligations of the
Company, enforceable in accordance with their terms except as (A) the
enforceability thereof may be limited by bankruptcy, insolvency or similar laws
affecting creditors' rights generally and (B) rights of acceleration and the
availability of equitable remedies may be limited by equitable principles of
general applicability.

           (h) The Securities conform as to legal matters in all material
respects to the description thereof contained in the Prospectus.

          (i) Neither the Company nor any of its Subsidiaries is in violation of
its respective charter or by-laws or in default in the performance of any
material obligation, agreement, covenant or condition contained in any
indenture, loan agreement, mortgage, note, lease or other agreement or
instrument to which the Company or any of its subsidiaries is a party or by
which it or any of them may be bound or to which any of the property or assets
of the Company or any of its subsidiaries is subject, except for any such
violation or default that would not have a material adverse effect on the
Company and its subsidiaries taken as a whole.

          (j) The Company and its Subsidiaries own, possess, license or can
acquire on reasonable terms, the material patents, patent rights, licenses,
inventions, copyrights, know-how (including trade secrets and other unpatented




                                        8
<PAGE>   9

and/or unpatentable proprietary or confidential information, systems or
procedures), service marks and trade names presently employed by them in
connection with the business now operated by them, and neither the Company nor
any of its Subsidiaries has received any notice of infringement of or conflict
with asserted rights of others with respect to any of the foregoing, except for
any such unfavorable decisions, rulings or findings which, singly or in the
aggregate, would not result in any material adverse change in the condition,
financial or otherwise, or in the earnings, business affairs or business
prospects of the Company and its subsidiaries considered as one enterprise.

   
          (k) The execution, delivery and performance of this Agreement, the
Indenture and the Securities by the Company, the compliance by the Company with
all the provisions hereof and thereof and the consummation of the transactions
contemplated hereby and thereby will not (i) require any consent, approval,
authorization or other order of, or qualification with, any court or
governmental body or agency (except such as may be required under (a) the Act,
(b) the Exchange Act or (c) the securities or Blue Sky laws of the various
states of the United States), (ii) conflict with or constitute a breach of any
of the terms or provisions of, or a default under, the charter or by-laws of the
Company or any of its Subsidiaries or any indenture, loan agreement, mortgage,
lease or other agreement or instrument that is material to the Company and its
Subsidiaries, taken as a whole, to which the Company or any of its Subsidiaries
is a party or by which the Company or any of its subsidiaries or their
respective property is bound, (iii) violate or conflict with any applicable law
or any rule, regulation, judgment, order or decree of any court or any
governmental body or agency having jurisdiction over the Company, any of its
Subsidiaries (other than the [Redland Subsidiaries]), and to the best of the
Company's knowledge, the [Redland Subsidiaries] or their respective property or
(iv) result in the imposition or creation of (or the obligation to create or
impose) a Lien under any agreement or instrument to which the Company or any of
its subsidiaries is a party or by which the Company or any of its subsidiaries
or their respective property is bound that is material to the Company and its
Subsidiaries, taken as a whole.
    

          (l) There is no action, suit or proceeding before or by any court or
governmental agency or body, domestic or foreign, now pending, or, to the
knowledge of the Company, threatened against or affecting, the Company or any of
its subsidiaries, which is required to be disclosed in the Prospectus (other
than as disclosed therein), or which might result in any material adverse change
in the condition, financial or otherwise, or in the earnings, business affairs
or business prospects of the Company and its subsidiaries considered as one
enterprise, or which might materially and adversely affect the properties or
assets thereof or which might materially and adversely affect the consummation
of this Agreement; all pending legal or governmental proceedings to which the
Company or any subsidiary is a party or of which any of their respective
properties or assets is the subject which are not described in the Prospectus,
including ordinary routine


                                       9
<PAGE>   10

litigation incidental to the business, are, considered in the aggregate, not
material; nor are there any statutes, regulations, contracts or other documents
that are required to be described in the Registration Statement or the
Prospectus or to be filed as exhibits to the Registration Statement that are not
so described or filed as required.

          (m) Except as described in the Prospectus, neither the Company nor any
of its Subsidiaries has violated any existing foreign, federal, state or local
law or regulation relating to the protection of human health and safety, the
environment or hazardous or toxic substances or wastes, pollutants or
contaminants ("Environmental Laws"), any provisions of the Employee Retirement
Income Security Act of 1974, as amended, or any provisions of the Foreign
Corrupt Practices Act or the rules and regulations promulgated thereunder,
except for such violations which, singly or in the aggregate, would not result
in any material adverse change in the condition, financial or otherwise, or in
the earnings, business affairs or business prospects of the Company and its
subsidiaries considered as one enterprise.

   
          (n) Except as described in the Prospectus, each of the Company and its
Subsidiaries has such permits, licenses, consents, exemptions, franchises,
authorizations and other approvals (each, an "Authorization") of, and has made
all filings with and notices to, all governmental or regulatory authorities and
self-regulatory organizations and all courts and other tribunals, including,
without limitation, under any applicable Environmental Laws, as are necessary to
own, lease, license and operate its respective properties and to conduct its
business, except where the failure to have any such Authorization or to make any
such filing or notice would not, singly or in the aggregate, have a material
adverse effect on the Company and its Subsidiaries considered as one enterprise.
Except as described in the Prospectus, each of the Company and its Subsidiaries
is in compliance in all material respects with all the terms and conditions
thereof and with the rules and regulations of the authorities and governing
bodies having jurisdiction with respect thereto; and no event has occurred
(including, without limitation, the receipt of any notice from any authority or
governing body) which allows or, after notice or lapse of time or both, would
allow, revocation, suspension or termination of any such Authorization or
results or, after notice or lapse of time or both, would result in any other
impairment of the rights of the holder of any such Authorization, except those
that would not have a material adverse effect on the Company and its
subsidiaries taken as a whole; and, except as described in the Prospectus, such
Authorizations contain no restrictions that are materially burdensome to the
Company or any of its subsidiaries; except where such failure to be valid and in
full force and effect or to be in compliance, the occurrence of any such event
or the presence of any such restriction would not, singly or in the aggregate,
result in any material adverse change in the condition, financial or otherwise,
or the earnings, business affairs or business prospects of the Company and its
subsidiaries considered as one enterprise.
    


                                       10
<PAGE>   11


           (o) Except as described in the Prospectus, there are no costs or
liabilities associated with Environmental Laws (including, without limitation,
any capital or operating expenditures required for clean-up, closure of
properties or compliance with Environmental Laws or any Authorization, any
related constraints on operating activities and any potential liabilities to
third parties) which would, singly or in the aggregate, result in any material
adverse change in the condition, financial or otherwise, or the earnings,
business affairs or business prospects of the Company and its subsidiaries
considered as one enterprise.

           (p) This Agreement has been duly authorized, executed and delivered
by the Company.

           (q) Arthur Andersen are independent public accountants with respect
to the Company and its subsidiaries as required by the Act and the rules and
regulations thereunder.

           (r) The consolidated financial statements included or incorporated by
reference in the Registration Statement and the Prospectus (and any amendment or
supplement thereto), together with related schedules and notes, present fairly
in all material respects the consolidated financial position, results of
operations and changes in financial position of the Company and its subsidiaries
on the basis stated therein at the respective dates or for the respective
periods to which they apply; such statements and related schedules and notes
have been prepared in accordance with generally accepted accounting principles
consistently applied throughout the periods involved, except as disclosed
therein; the supporting schedules, if any, included in the Registration
Statement present fairly in all material respects in accordance with generally
accepted accounting principles the information required to be stated therein;
and the other financial and statistical information and data set forth in the
Registration Statement and the Prospectus (and any amendment or supplement
thereto) are, in all material respects, accurately presented and prepared on a
basis consistent with such financial statements and the books and records of the
Company.

          (s) The Company is not and, after giving effect to the offering and
sale of the Securities and the application of the proceeds thereof as described
in the Prospectus, will not be, an "investment company" as such term is defined
in the Investment Company Act of 1940, as amended.

          (t) There are no contracts, agreements or understandings between the
Company and any person granting such person the right to require the Company to
file a registration statement under the Act with respect to any securities of
the Company or to require the Company to include such securities with the
Securities registered pursuant to the Registration Statement.

           (u) No "nationally recognized statistical rating organization" as
such term is defined for purposes of Rule 436(g)(2) under the Act has indicated
to the Company that it is considering (i) the downgrading, suspension or
withdrawal of,



                                       11
<PAGE>   12

or any review for a possible change that does not indicate the direction of the
possible change in, any rating assigned to the Company or any securities of the
Company or (ii) any change in the outlook for any rating of the Company or any
securities of the Company.

           (v) Since the respective dates as of which information is given in
the Prospectus other than as set forth in the Prospectus (exclusive of any
amendments or supplements thereto subsequent to the date of this Agreement), (i)
there has not occurred any material adverse change in the condition, financial
or otherwise, or the earnings or business affairs of the Company and its
subsidiaries, considered as one enterprise, whether or not arising in the
ordinary course of business, (ii) there has not been any material adverse change
in the capital stock or in the long-term debt of the Company or any of its
subsidiaries and (iii) there have been no transactions entered into by the
Company or any of its subsidiaries, other than those in the ordinary course of
business, which are material with respect to the Company and its subsidiaries
considered as one enterprise.

         SECTION 7. Indemnification. (a) The Company agrees to indemnify and
hold harmless each Underwriter, its directors, its officers and each person, if
any, who controls any Underwriter within the meaning of Section 15 of the Act or
Section 20 of the Exchange Act, from and against any and all losses, claims,
damages, liabilities and judgments (including, without limitation, any
reasonable legal or other expenses incurred in connection with investigating or
defending any matter, including any action, that could give rise to any such
losses, claims, damages, liabilities or judgments) caused by any untrue
statement or alleged untrue statement of a material fact contained in the
Registration Statement (or any amendment thereto), the Prospectus (or any
amendment or supplement thereto) or any preliminary prospectus, or caused by any
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading,
except insofar as such losses, claims, damages, liabilities or judgments are
caused by any such untrue statement or omission or alleged untrue statement or
omission based upon information relating to any Underwriter furnished in writing
to the Company by or on behalf of such Underwriter through you expressly for use
therein; provided, however, that the foregoing indemnity agreement with respect
to any preliminary prospectus shall not inure to the benefit of any Underwriter
who failed to deliver a Prospectus, as then amended or supplemented, (so long as
the Prospectus and any amendment or supplemented thereto was provided by the
Company to the several Underwriters in the requisite quantity and on a timely
basis to permit proper delivery on or prior to the Closing Date) to the person
asserting any losses, claims, damages, liabilities or judgements caused by any
untrue statement or alleged untrue statement of a material fact contained in the
preliminary prospectus, or caused by any omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading, if such material misstatement or omission or
alleged material misstatement or omission was cured in the Prospectus, as so
amended or supplemented, and such Prospectus was



                                       12
<PAGE>   13

required by law to be delivered at or prior to the written confirmation of sale
to such person.

          (b) Each Underwriter agrees, severally and not jointly, to indemnify
and hold harmless the Company, its directors, its officers who sign the
Registration Statement and each person, if any, who controls the Company within
the meaning of Section 15 of the Act or Section 20 of the Exchange Act, to the
same extent as the foregoing indemnity from the Company to such Underwriter but
only with reference to information relating to such Underwriter furnished in
writing to the Company by such Underwriter through you expressly for use in the
Registration Statement (or any amendment thereto), the Prospectus (or any
amendment or supplement thereto) or any preliminary prospectus.

           (c) In case any action shall be commenced involving any person in
respect of which indemnity may be sought pursuant to Section 7(a) or 7(b) (the
"indemnified party"), the indemnified party shall promptly notify the person
against whom such indemnity may be sought (the "indemnifying party") in writing
and the indemnifying party shall assume the defense of such action, including
the employment of counsel reasonably satisfactory to the indemnified party and
the payment of all fees and expenses of such counsel, as incurred (except that
in the case of any action in respect of which indemnity may be sought pursuant
to both Sections 7(a) and 7(b), the Underwriter shall not be required to assume
the defense of such action pursuant to this Section 7(c), but may employ
separate counsel and participate in the defense thereof, but the fees and
expenses of such counsel, except as provided below, shall be at the expense of
such Underwriter). Any indemnified party shall have the right to employ separate
counsel in any such action and participate in the defense thereof, but the fees
and expenses of such counsel shall be at the expense of the indemnified party
unless (i) the employment of such counsel shall have been specifically
authorized in writing by the indemnifying party, (ii) the indemnifying party
shall have failed to assume the defense of such action or employ counsel
reasonably satisfactory to the indemnified party within a reasonably prompt
period of time following the receipt of notification in writing from the
indemnified party, or (iii) the named parties to any such action (including any
impleaded parties) include both the indemnified party and the indemnifying
party, and the indemnified party shall have been advised by such counsel that
there may be one or more legal defenses available to it which are different from
or additional to those available to the indemnifying party (in which case the
indemnifying party shall not have the right to assume the defense of such action
on behalf of the indemnified party). In any such case, the indemnifying party
shall not, in connection with any one action or separate but substantially
similar or related actions in the same jurisdiction arising out of the same
general allegations or circumstances, be liable for the reasonable fees and
expenses of more than one separate firm of attorneys (in addition to any local
counsel) for all indemnified parties and all such reasonable fees and expenses
shall be reimbursed as they are incurred. Such firm shall be designated in
writing by Donaldson, Lufkin & Jenrette Securities Corporation, in the case of
parties indemnified pursuant to Section 7(a), and by the Company, in the case of





                                       13
<PAGE>   14

   
parties indemnified pursuant to Section 7(b). The indemnifying party shall
indemnify and hold harmless the indemnified party from and against any and all
losses, claims, damages, liabilities and judgments by reason of any settlement
of any action (i) effected with its written consent or (ii) effected without its
written consent if the settlement is entered into more than twenty business days
after the indemnifying party shall have received a request from the indemnified
party for reimbursement for the fees and expenses of counsel (in any case where
such fees and expenses are at the expense of the indemnifying party) and, prior
to the date of such settlement, the indemnifying party shall have failed to
comply with such reimbursement request. No indemnifying party shall, without the
prior written consent of the indemnified party, effect any settlement or
compromise of, or consent to the entry of judgment with respect to, any pending
or threatened action in respect of which the indemnified party is or could have
been a party and indemnity or contribution may be or could have been sought
hereunder by the indemnified party, unless such settlement, compromise or
judgment (i) includes an unconditional release of the indemnified party from all
liability on claims that are or could have been the subject matter of such
action and (ii) does not include a statement as to or an admission of fault,
culpability or a failure to act, by or on behalf of the indemnified party. No
indemnifying party will be liable for the costs and expenses of any settlement
of any pending or threatened action effected by the indemnified party without
the consent of the indemnifying party.
    

          (d) To the extent the indemnification provided for in this Section 7
is unavailable to an indemnified party or insufficient in respect of any losses,
claims, damages, liabilities or judgments referred to therein, then each
indemnifying party, in lieu of indemnifying such indemnified party, shall
contribute to the amount paid or payable by such indemnified party as a result
of such losses, claims, damages, liabilities and judgments (i) in such
proportion as is appropriate to reflect the relative benefits received by the
Company on the one hand and the Underwriters on the other hand from the offering
of the Securities or (ii) if the allocation provided by clause 7(d)(i) above is
not permitted by applicable law, in such proportion as is appropriate to reflect
not only the relative benefits referred to in clause 7(d)(i) above but also the
relative fault of the Company on the one hand and the Underwriters on the other
hand in connection with the statements or omissions which resulted in such
losses, claims, damages, liabilities or judgments, as well as any other relevant
equitable considerations. The relative benefits received by the Company on the
one hand and the Underwriters on the other hand shall be deemed to be in the
same proportion as the total net proceeds from the offering (after deducting
underwriting discounts and commissions but before deducting expenses) received
by the Company, and the total underwriting discounts and commissions received by
the Underwriters, bear to the total price to the public of the Securities, in
each case as set forth in the table on the cover page of the Prospectus. The
relative fault of the Company on the one hand and the Underwriters on the other
hand shall be determined by reference to, among other things, whether the untrue
or alleged untrue statement of a material fact or the omission or alleged
omission to state a material fact relates to information supplied by the Company
or the Underwriters and the parties' relative intent,




                                       14
<PAGE>   15

knowledge, access to information and opportunity to correct or prevent such
statement or omission.

         The Company and the Underwriters agree that it would not be just and
equitable if contribution pursuant to this Section 7(d) were determined by pro
rata allocation (even if the Underwriters were treated as one entity for such
purpose) or by any other method of allocation which does not take account of the
equitable considerations referred to in the immediately preceding paragraph. The
amount paid or payable by an indemnified party as a result of the losses,
claims, damages, liabilities or judgments referred to in the immediately
preceding paragraph shall be deemed to include, subject to the limitations set
forth above, any legal or other expenses reasonably incurred by such indemnified
party in connection with investigating or defending any matter, including any
action, that could have given rise to such losses, claims, damages, liabilities
or judgments. Notwithstanding the provisions of this Section 7, no Underwriter
shall be required to contribute any amount in excess of the amount by which the
total price at which the Securities underwritten by it and distributed to the
public were offered to the public exceeds the amount of any damages which such
Underwriter has otherwise been required to pay by reason of such untrue or
alleged untrue statement or omission or alleged omission. No person guilty of
fraudulent misrepresentation (within the meaning of Section 11(f) of the Act)
shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation. The Underwriters' obligations to contribute
pursuant to this Section 7(d) are several in proportion to the respective
principal amount of Securities purchased by each of the Underwriters hereunder
and not joint.

          (e) The remedies provided for in this Section 7 are not exclusive and
shall not limit any rights or remedies which may otherwise be available to any
indemnified party at law or in equity.

         SECTION 8. Conditions of Underwriters' Obligations. The several
obligations of the Underwriters to purchase the Securities under this Agreement
are subject to the satisfaction of each of the following conditions:

          (a) All the representations and warranties of the Company contained in
this Agreement shall be true and correct on the Closing Date with the same force
and effect as if made on and as of the Closing Date.

          (b) If the Company is required to file a Rule 462(b) Registration
Statement after the effectiveness of this Agreement, such Rule 462(b)
Registration Statement shall have become effective by the earlier of 10:00 A.M.,
New York City time, on the date after the date of this Agreement and the time
confirmations are first sent or given for the Securities; and no stop order
suspending the effectiveness of the Registration Statement shall have been
issued and no proceedings for that purpose shall have been commenced or shall be
pending before or contemplated by the Commission.




                                       15
<PAGE>   16


          (c) On or after the date hereof, (i) there shall not have occurred any
downgrading, suspension or withdrawal of, nor shall any notice have been given
of any potential or intended downgrading, suspension or withdrawal of, or of any
review (or of any potential or intended review) for a possible change that does
not indicate the direction of the possible change in, any rating of the Company
or any securities of the Company (including, without limitation, the placing of
any of the foregoing ratings on credit watch with negative or developing
implications or under review with an uncertain direction) by any "nationally
recognized statistical rating organization" as such term is defined for purposes
of Rule 436(g)(2) under the Act, (ii) there shall not have occurred any change,
nor shall any notice have been given of any potential or intended change, in the
outlook for any rating of the Company or any securities of the Company by any
such rating organization and (iii) no such rating organization shall have given
notice that it has assigned (or is considering assigning) a lower rating to the
Securities than that on which the Securities were marketed.

          (d) You shall have received on the Closing Date a certificate dated
the Closing Date, signed by the Chief Executive Officer and the Chief Financial
Officer of the Company, confirming the matters set forth in Sections 6(w), 8(a),
8(b) and 8(c) and that the Company has complied with all of the agreements and
satisfied all of the conditions herein contained and required to be complied
with or satisfied by the Company on or prior to the Closing Date.

          (e) Since the respective dates as of which information is given in the
Prospectus other than as set forth in the Prospectus (exclusive of any
amendments or supplements thereto subsequent to the date of this Agreement), (i)
there shall not have occurred any change or any development involving a
prospective change in the condition, financial or otherwise, or the earnings,
business, management or operations of the Company and its subsidiaries, taken as
a whole, (ii) there shall not have been any change or any development involving
a prospective change in the capital stock or in the long-term debt of the
Company or any of its subsidiaries and (iii) neither the Company nor any of its
subsidiaries shall have incurred any liability or obligation, direct or
contingent, the effect of which, in any such case described in clause 8(e)(i),
8(e)(ii) or 8(e)(iii), in your judgment, is material and adverse and, in your
judgment, makes it impracticable to market the Securities on the terms and in
the manner contemplated in the Prospectus.

          (f) You shall have received on the Closing Date an opinion
(satisfactory to you and counsel for the Underwriters), dated the Closing Date,
of Thompson & Knight, P.C., counsel for the Company, to the effect that:

   

    

                                       16
<PAGE>   17


   
                  (i) the Securities have been duly authorized and, when
         executed and authenticated in accordance with the provisions of the
         Indenture and delivered to and paid for by the Underwriters in
         accordance with the terms of this Agreement, will be entitled to the
         benefits of the Indenture and will be valid and binding obligations of
         the Company, enforceable in accordance with their terms except as (A)
         the enforceability thereof may be limited by bankruptcy, insolvency or
         similar laws affecting creditors' rights generally and (B) rights of
         acceleration and the availability of equitable remedies may be limited
         by equitable principles of general applicability; in rendering the
         foregoing opinion that the Securities will be valid and binding
         obligations of the Company enforceable against the Company in
         accordance with their respective terms, such counsel may assume that
         the law of New York is identical to the law of Texas in all respects
         material to such opinion.
    

                (iii) the Indenture as supplemented by the Supplemental
         Indenture has been duly qualified under the Trust Indenture Act and has
         been duly authorized, executed and delivered by the Company and is a
         valid and binding agreement of the Company, enforceable in accordance
         with its terms except as (A) the enforceability thereof may be limited
         by bankruptcy, insolvency or similar laws affecting creditors' rights
         generally and (B) rights of acceleration and the availability of
         equitable remedies may be limited by equitable principles of general
         applicability; in rendering the foregoing opinion that the Indenture as
         supplemented by the Supplemental Indenture constitutes a valid and
         binding agreement of the Company enforceable in accordance with its
         terms, such counsel may assume that the law of New York is identical to
         the law of Texas in all respects material to such opinion;

                  (iv) this Agreement has been duly authorized, executed and
         delivered by the Company;

                  (v) the Registration Statement has become effective under the
         Act, no stop order suspending its effectiveness has been issued and no
         proceedings for that purpose are, to the best of such counsel's
         knowledge, pending before or contemplated by the Commission;

                 (vi) the statements under the caption "Description of Notes" in
         the Prospectus and Item 15 of Part II of the Registration Statement,
         insofar as such statements constitute a summary of the legal matters,
         documents or proceedings referred to therein, fairly present the
         information called for with respect to such legal matters, documents
         and proceedings;

                (vii) the execution, delivery and performance of this Agreement,
         the Indenture and the Securities by the Company, the compliance by the
         Company with all the provisions hereof and thereof and the consummation
         of the transactions contemplated hereby and thereby will not (A)
         require any consent, approval, authorization or other order of, or
         qualification with, any court or governmental body or agency of the
         United States of America or except for any such consent, approval or
         authorization, or order, which, if not obtained, would not prevent or
         adversely effect in any 




                                       17
<PAGE>   18
   
         material respect the performance of this Agreement or have a material
         adverse effect on the Company and its subsidiaries, taken as a whole
         (except such as may be required under the Act, the Exchange Act and the
         securities or Blue Sky laws of the various states of the United States)
         or violate or conflict with any federal securities law or any other law
         or rule, regulation, judgment, order or decree known to such counsel to
         be applicable to the Company or any of its subsidiaries of any court or
         any governmental body or agency having jurisdiction over the Company,
         any of its subsidiaries or their respective property (provided,
         however, that such counsel need express no opinion with respect to
         compliance with any state securities law except as otherwise
         specifically stated in such counsel's opinion); and
    

                (viii) the Registration Statement and the Prospectus and any
         supplement or amendment thereto (except for the financial statements
         and other financial data (including the notes thereto and the auditor's
         report thereon) included therein as to which no opinion need be
         expressed) comply as to form in all material respects with the Act and
         the Trust Indenture Act and the regulations under each of those Acts.

         The opinion of Thompson & Knight, P.C. described in Section 8(f) above
shall be rendered to you at the request of the Company and shall so state
therein.

   
          (g) Thompson & Knight, P.C., in rendering the opinions referred to in
subsection (f) of this Section, may rely as to all matters relating to the laws
of the State of Maryland upon an opinion of Piper & Marbury, dated the date
thereof, in form and substance satisfactory to counsel for the Underwriters, a
copy of which shall have been furnished to the Underwriters. Milbank, Tweed,
Hadley & McCloy, in rendering the opinion referred to in subsection (i) of this
Section, may rely as to all matters relating to the laws of the State of
Maryland upon such opinion of Piper & Marbury. In giving their opinions required
by subsection (f) and (i) of this Section, Thompson & Knight, P.C., and Milbank,
Tweed, Hadley & McCloy, shall each additionally state that nothing has come to
their attention that would lead them to believe that the Registration Statement,
at the time it became 
    





                                       18
<PAGE>   19

effective, and if an amendment to the Registration Statement or a filing of a
report on Form 10-K, 10-Q or 8-K has been filed by the Company with the
Commission under the Act or the Exchange Act, respectively, subsequent to the
effectiveness of the Registration Statement, then at the time such amendment
became effective or at the time of the most recent such filing, and at the date
hereof, contained an untrue statement of a material fact or omitted to state a
material fact required to be stated therein or necessary to make the statements
therein not misleading or that the Prospectus, as amended or supplemented at the
date hereof, contains an untrue statement of a material fact or omits to state a
material fact necessary in order to make the statements therein, in the light of
the circumstances under which they were made, not misleading.

           (h) You shall have received on the Closing Date an opinion
(satisfactory to you and counsel for the Underwriters), dated the Closing Date,
of David C. Jones, Vice President Legal Affairs of the Company, to the effect
that:

                   (i) each of the Company and its Subsidiaries has been duly
         incorporated, is validly existing as a corporation in good standing
         under the laws of its jurisdiction of incorporation and has the
         corporate power and authority to carry on its business as described in
         the Prospectus and to own, lease and operate its properties;

                  (ii) to the best of such counsel's knowledge, each of the
         Company and its Subsidiaries is duly qualified and is in good standing
         as a foreign corporation authorized to do business in each jurisdiction
         in which the nature of its business or its ownership or leasing of
         property requires such qualification, except where the failure to be so
         qualified would not have a material adverse effect on the business,
         prospects, financial condition or results of operations of the Company
         and its subsidiaries, taken as a whole;

   
                 (iii) all of the outstanding shares of capital stock of each of
         (x) the Company's Subsidiaries (other than Lafarge Canada Inc. and the
         Redland Subsidiaries) and (y) to the best of such counsels knowledge,
         the [Redland Subsidiaries], have been duly authorized and validly
         issued and are fully paid and non-assessable, and are owned by the
         Company, directly or indirectly through one or more subsidiaries, free
         and clear of any Lien;
    

                  (iv) the Securities have been duly authorized and executed;

                   (v) the Indenture has been duly authorized, executed and
         delivered by the Company;

                  (vi) this Agreement has been duly authorized, executed and
         delivered by the Company;

                 (vii) neither the Company nor any of its Subsidiaries, or to
         the best of such counsel's knowledge, the Redland Subsidiaries, is in
         violation






                                       19
<PAGE>   20

         of its respective charter or by-laws and, to the best of such counsel's
         knowledge, neither the Company nor any of its Subsidiaries is in
         default in the performance of any obligation, agreement, covenant or
         condition contained in any indenture, loan agreement, mortgage, lease
         or other agreement or instrument that is material to the Company and
         its subsidiaries, taken as a whole, to which the Company or any of its
         subsidiaries is a party or by which the Company or any of its
         subsidiaries or their respective property is bound;

   
                (viii) the execution, delivery and performance of this
         Agreement, the Indenture and the Securities by the Company, the
         compliance by the Company with all the provisions hereof and thereof
         and the consummation of the transactions contemplated hereby and
         thereby will not (A) require any consent, approval, authorization or
         other order of, or qualification with, any court or governmental body
         or agency of the United States of America or the State of Maryland or
         except for any such consent, approval or authorization, or order,
         which, if not obtained, would not prevent or adversely effect in any
         material respect the performance of this Agreement or have a material
         adverse effect on the Company and its subsidiaries, taken as a whole
         (except such as may be required under the Act, the Exchange Act and the
         securities or Blue Sky laws of the various states of the United
         States), (B) conflict with or constitute a breach of any of the terms
         or provisions of, or a default under, the charter or by-laws of the
         Company or any of its Subsidiaries or to such counsel's knowledge, any
         indenture, loan agreement, mortgage, lease or other agreement or
         instrument that is material to the Company and its subsidiaries, taken
         as a whole, to which the Company or any of its subsidiaries is a party
         or by which the Company or any of its subsidiaries or their respective
         property is bound, (C) violate or conflict with any federal securities
         law or any other law or rule, regulation, judgment, order or decree
         known to such counsel to be applicable to the Company or any of its
         subsidiaries of any court or any governmental body or agency having
         jurisdiction over the Company, any of its subsidiaries or their
         respective property (provided, however, that such counsel need express
         no opinion with respect to compliance with any federal or state
         securities law or antitrust law, rule or regulation except as otherwise
         specifically stated in such counsel's opinion, (D) result in the
         imposition or creation of (or the obligation to create or impose) a
         Lien under any material agreement or instrument to which the Company or
         any of its subsidiaries is a party or by which the Company or any of
         its subsidiaries other than the [Redland Subsidiaries], or to the best
         of such counsel's knowledge, the Redland Subsidiaries or their
         respective property is bound or (E) to the knowledge of such counsel,
         result in the suspension, termination or revocation of any
         Authorization of the Company or any of its subsidiaries or any other
         impairment of the rights of the holder of any such Authorization;
    

                  (ix) such counsel does not know of any legal or governmental
         proceedings pending or threatened to which the Company or any of its
         subsidiaries is or could be a party or to which any of their respective





                                       20
<PAGE>   21

         property is or could be subject that are required to be described in
         the Registration Statement or the Prospectus and are not so described;

                   (x) the information in the 10-K Report under the caption
         "Legal Proceedings", as amended or supplemented in any report filed by
         the Company with the Commission under the Exchange Act, to the extent
         that it constitutes matters of United States law or legal conclusions,
         has been reviewed by such counsel and is correct in all material
         aspects;

   
                  (xi) to the best of such counsel's knowledge, there are no
         contracts, indentures, mortgages, loan agreements, notes, leases or
         other instruments or documents required to be described or referred to
         in the Registration Statement or to be filed as exhibits thereto other
         than those described or referred to therein or filed or incorporated by
         reference as exhibits thereto; the descriptions thereof or references
         thereto are correct in all material respects, and no default exists in
         the due performance or observance of any material obligation,
         agreement, covenant or condition contained in any contract, indenture,
         mortgage, loan agreement, note, lease or other instrument so described,
         referred to, filed or incorporated by reference; and
    

   
                 (xii) to the best of such counsel's knowledge after due
         inquiry, there are no contracts, agreements or understandings between
         the Company and any person granting such person the right to require
         the Company to file a registration statement under the Act with respect
         to any securities of the Company or to require the Company to include
         such securities with the Securities registered pursuant to the
         Registration Statement.
    

   

    
                
           (i) The favorable opinion of, Alain Fredette, Manager, Legal Services
and Secretary of Lafarge Canada Inc. to the effect that Lafarge Canada Inc. has
been duly incorporated and is validly existing as a corporation under the laws
of Canada and has corporate power and authority to own, lease and operate its
properties and conduct its business as described in the Registration Statement
and, to the best of his knowledge and information, is duly qualified as a
foreign corporation to transact business and is in good standing in each
jurisdiction in which it owns or leases substantial properties or in which the
conduct of its business requires such qualification, except where the failure to
so qualify or be in good standing would not have a material adverse effect on
the condition, financial or otherwise, or the earnings, business affairs or
business prospects of Lafarge





                                       21
<PAGE>   22

Canada Inc.; and all of the issued and outstanding shares of capital stock of
Lafarge Canada Inc. have been duly and validly issued and are fully paid and
non-assessable.
           
   
           (j) You shall have received on the Closing Date an opinion
(satisfactory to you and counsel for the Underwriters), dated the Closing Date,
of Piper & Marbury, counsel for the Company, to the effect that:
    

   
                  (i)   the Company and each of its Subsidiaries incorporated
           under the laws of the State of Maryland has been duly incorporated
           and is validly existing as a corporation in good standing under the
           laws of Maryland;
    

   
                  (ii)  the Company has corporate power and authority to carry
           on its business as described in the Prospectus and to own, lease and
           operate its properties;
    

   
                  (iii) the Securities have been duly authorized and, when
           executed and authenticated in accordance with the provisions of the
           Indenture and delivered to and paid for by the Underwriters in
           accordance with the terms of this Agreement, will be entitled to the
           benefits of the Indenture and will be valid and binding obligations
           of the Company, enforceable in accordance with their terms except as
           (A) the enforceability thereof may be limited by bankruptcy,
           insolvency or similar laws affecting creditors' rights generally and
           (B) rights of acceleration and the availability of equitable remedies
           may be limited by equitable principles of general applicability; in
           rendering the foregoing opinion that the Securities will be valid and
           binding obligations of the Company enforceable against the Company in
           accordance with their respective terms, such counsel may assume that
           the law of New York is identical to the law of Maryland in all
           respects material to such opinion;
    

   
                  (iv)  the Indenture has been duly and validly authorized,
           executed and delivered by the Company and is a valid and binding
           agreement of the Company, enforceable in accordance with its terms
           except as (A) the enforceability thereof may be limited by
           bankruptcy, insolvency or similar laws affecting creditors' rights
           generally and (B) rights of acceleration and the availability of
           equitable remedies may be limited by equitable principles of general
           applicability; in rendering the foregoing opinion that the Indenture
           is a valid and binding agreement of the Company, enforceable in
           accordance with its terms, such counsel may assume that the law of
           New York is identical to the law of Maryland in all respects material
           to such opinion; and
    

   
                  (v)   this Agreement has been duly authorized, executed and
           delivered by the Company.
    
      
   
           (k) You shall have received on the Closing Date an opinion, dated the
Closing Date, of Milbank, Tweed, Hadley & McCloy, counsel for the Underwriters,
as to the matters referred to in Sections 8(f)(i), 8(f)(ii), 8(f)(iii),
8(f)(v) (but only with respect to the statements under the caption "Description
of Notes") and 8(f)(vii)].
    

   
           (l) You shall have received, on each of the date hereof and the
Closing Date, a letter dated the date hereof or the Closing Date, as the case
may be, in form and substance satisfactory to you, from Arthur Andersen,
independent public accountants, containing the information and statements of the
type ordinarily included in accountants' "comfort letters" to Underwriters with
respect to the financial statements and certain financial information contained
in the Registration Statement and the Prospectus.
    

   
           (m) The Securities shall have been rated "A-" by Standard & Poor's
Corporation and "Baa1" by Moody's Investors Service, Inc.
    

   
           (n) The Underwriters shall have received a counterpart, conformed as
executed, of the Indenture which shall have been entered into by the Company and
the Trustee.
    

   
           (o) The Company shall not have failed on or prior to the Closing Date
to perform or comply with any of the agreements herein contained and required to
be performed or complied with by the Company on or prior to the Closing Date.
    

         SECTION 9. Effectiveness of Agreement and Termination. This Agreement
shall become effective upon the execution and delivery of this Agreement by the
parties hereto.

         This Agreement may be terminated at any time on or prior to the Closing
Date by you by written notice to the Company if any of the following has
occurred: (i) any outbreak or escalation of hostilities or other national or
international calamity or crisis or change in economic conditions or in the
financial markets of the United States or elsewhere that, in your judgment, is
material and adverse and, in your judgment, makes it impracticable to market the
Securities on the terms and in the manner contemplated in the Prospectus, (ii)
the suspension or material limitation of trading in securities or other
instruments on the New York Stock Exchange, the American Stock Exchange, the
Chicago Board of Options Exchange, the Chicago Mercantile Exchange, the Chicago
Board of Trade or the Nasdaq National Market or limitation on prices for
securities or other instruments on any such exchange or the Nasdaq National
Market, (iii) the suspension of trading of any securities of the Company on any
exchange or in the over-the-counter market, (iv) the enactment, publication,






                                       22
<PAGE>   23

decree or other promulgation of any federal or state statute, regulation, rule
or order of any court or other governmental authority which in your opinion
materially and adversely affects, or will materially and adversely affect, the
business, prospects, financial condition or results of operations of the Company
and its subsidiaries, taken as a whole, (v) the declaration of a banking
moratorium by either federal or New York State authorities or (vi) the taking of
any action by any federal, state or local government or agency in respect of its
monetary or fiscal affairs which in your opinion has a material adverse effect
on the financial markets in the United States.

         If on the Closing Date any one or more of the Underwriters shall fail
or refuse to purchase the Securities which it or they have agreed to purchase
hereunder on such date and the aggregate principal amount of Securities which
such defaulting Underwriter or Underwriters agreed but failed or refused to
purchase is not more than one-tenth of the aggregate principal amount of
Securities to be purchased on such date by all Underwriters, each non-defaulting
Underwriter shall be obligated severally, in the proportion which the principal
amount of Securities set forth opposite its name in Schedule I bears to the
aggregate principal amount of Securities which all the non-defaulting
Underwriters have agreed to purchase, or in such other proportion as you may
specify, to purchase the Securities which such defaulting Underwriter or
Underwriters agreed but failed or refused to purchase on such date; provided
that in no event shall the aggregate principal amount of Securities which any
Underwriter has agreed to purchase pursuant to Section 2 hereof be increased
pursuant to this Section 9 by an amount in excess of one-ninth of such principal
amount of Securities without the written consent of such Underwriter. If on the
Closing Date any Underwriter or Underwriters shall fail or refuse to purchase
Securities and the aggregate principal amount of Securities with respect to
which such default occurs is more than one-tenth of the aggregate principal
amount of Securities to be purchased by all Underwriters and arrangements
satisfactory to you and the Company for purchase of such Securities are not made
within 48 hours after such default, this Agreement will terminate without
liability on the part of any non-defaulting Underwriter and the Company. In any
such case which does not result in termination of this Agreement, either you or
the Company shall have the right to postpone the Closing Date, but in no event
for longer than seven days, in order that the required changes, if any, in the
Registration Statement and the Prospectus or any other documents or arrangements
may be effected. Any action taken under this paragraph shall not relieve any
defaulting Underwriter from liability in respect of any default of any such
Underwriter under this Agreement.

         SECTION 10. Miscellaneous. Notices given pursuant to any provision of
this Agreement shall be addressed as follows: (i) if to the Company, to Lafarge
Corporation, 11130 Sunrise Valley Drive, Suite 300, Reston, Virginia 22091,
Attention: Sharon Collins Casey and (ii) if to any Underwriter or to you, to you
c/o Donaldson, Lufkin & Jenrette Securities Corporation, 277 Park Avenue, New





                                       23
<PAGE>   24

York, New York 10172, Attention: Syndicate Department, or in any case to such
other address as the person to be notified may have requested in writing.

         The respective indemnities, contribution agreements, representations,
warranties and other statements of the Company and the several Underwriters set
forth in or made pursuant to this Agreement shall remain operative and in full
force and effect, and will survive delivery of and payment for the Securities,
regardless of (i) any investigation, or statement as to the results thereof,
made by or on behalf of any Underwriter, the officers or directors of any
Underwriter, any person controlling any Underwriter, the Company, the officers
or directors of the Company or any person controlling the Company, (ii)
acceptance of the Securities and payment for them hereunder and (iii)
termination of this Agreement.

         If for any reason the Securities are not delivered by or on behalf of
the Company as provided herein (other than as a result of any termination of
this Agreement pursuant to Section 9), the Company agrees to reimburse the
several Underwriters for all out-of-pocket expenses (including the fees and
disbursements of counsel) incurred by them. Notwithstanding any termination of
this Agreement, the Company shall be liable for all expenses which it has agreed
to pay pursuant to Section 5(j) hereof. The Company also agrees to reimburse the
several Underwriters, their directors and officers and any persons controlling
any of the Underwriters for any and all fees and expenses (including, without
limitation, the fees disbursements of counsel) incurred by them in connection
with enforcing their rights hereunder (including, without limitation, pursuant
to Section 7 hereof).

         Except as otherwise provided, this Agreement has been and is made
solely for the benefit of and shall be binding upon the Company, the
Underwriters, the Underwriters' directors and officers, any controlling persons
referred to herein, the Company's directors and the Company's officers who sign
the Registration Statement and their respective successors and assigns, all as
and to the extent provided in this Agreement, and no other person shall acquire
or have any right under or by virtue of this Agreement. The term "successors and
assigns" shall not include a purchaser of any of the Securities from any of the
several Underwriters merely because of such purchase.

         This Agreement shall be governed and construed in accordance with the
laws of the State of New York.

         This Agreement may be signed in various counterparts which together
shall constitute one and the same instrument.



                                       24
<PAGE>   25





         Please confirm that the foregoing correctly sets forth the agreement
between the Company and the several Underwriters.



                                                Very truly yours,

                                                LAFARGE CORPORATION


                                                By:
                                                   -----------------------------
                                                   Title:



DONALDSON, LUFKIN & JENRETTE
  SECURITIES CORPORATION
WARBURG DILLON READ LLC
CITICORP SECURITIES, INC.

   
    

By   DONALDSON, LUFKIN & JENRETTE
         SECURITIES CORPORATION



   By
     ---------------------------------





                                       25
<PAGE>   26






                                   SCHEDULE I



                                                             Principal Amount
                 Underwriters                                of Senior Notes
                 ------------                                ----------------

            
Donaldson, Lufkin & Jenrette Securities Corporation
Warburg Dillon Read LLC
Citicorp Securities, Inc.
                                                               -----------
            Total