<PAGE>

                 AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER


          THIS AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER (this
"Agreement"), dated as of October 2, 1998, is made by and among D and W
Holdings, Inc., a Delaware corporation ("Parent"), and the individuals set forth
on the signature pages hereto (collectively, the "Rolling Securityholders").

                             PRELIMINARY STATEMENTS

          A. Parent, D and W Acquisition Corp., a Delaware corporation ("Sub"),
Atrium Corporation, a Delaware corporation (the "Company"), and the
securityholders of the Company entered into an Agreement and Plan of Merger,
dated as of August 3, 1998 (the "Merger Agreement"), with respect to the merger
of Sub with and into the Company.

          B. Capitalized terms used and not defined herein shall have the
respective meanings ascribed to them in the Merger Agreement.

          C. As contemplated by Sections 7.6 and 13.2 of the Merger Agreement,
some or all of the Shares and/or Options held by the Rolling Securityholders
shall be converted into shares of Common Stock, par value $.01 per share, of
Parent ("Parent Common Stock") or options to purchase Parent Common Stock, as
applicable.

          D. To this end, the parties hereto wish to amend certain of the terms
and conditions of the Merger Agreement.

                                   AGREEMENTS

          NOW, THEREFORE, in consideration of the covenants and agreements set
forth herein and in the Merger Agreement, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, and
upon the terms and conditions hereinafter set forth, the parties hereto,
intending to be legally bound, agree as follows:

          1. AMENDMENT TO MERGER AGREEMENT.

          (a) The first sentence of Section 2.9(a) of the Merger Agreement shall
be deleted in its entirety and replaced with the following:


<PAGE>

               At the Closing, Parent and the Surviving Corporation shall
               transfer to a bank or trust company designated by Parent (the
               "Exchange Agent"), by wire transfer of immediately available
               funds, cash in an amount equal to (i) the Merger Consideration,
               minus (ii) the aggregate amount paid to Securityholders pursuant
               to Paragraph 2.9(b), minus (iii) the Escrow Amount, minus (iv)
               the Company Transaction Costs Holdback Amount, minus (v) the
               Aggregate Rolled Amount (as herein defined).

                    (b) Each Rolling Securityholder acknowledges and agrees 
that, notwithstanding the provisions of Sections 2.9(a) and 2.9(b) of the Merger
Agreement:

                         (i) such Rolling Securityholder will not be eligible to
               receive a portion of the Merger Consideration in cash from Parent
               and/or the Exchange Agent in the manner set forth in Sections
               2.9(a) and 2.9(b) of the Merger Agreement in exchange for the
               Common Stock set forth beside such Rolling Securityholder's name
               on EXHIBIT A hereto (the "Rolled Common Stock") or the Options
               set forth beside such Rolling Securityholder's name on EXHIBIT B
               hereto (the "Rolled Options"); and

                         (ii) to the extent that such Rolling Securityholder is 
               not eligible to receive a portion of the Merger Consideration as
               contemplated by Section 1(b)(i) of this Agreement, such Rolling
               Securityholder shall receive Parent Common Stock or options to
               purchase Parent Common Stock, as applicable, as set forth in, and
               subject to the terms and conditions of, the Subscription
               Agreement by and between Parent and such Rolling Securityholder
               dated as of October 2, 1998 and/or the Replacement Stock Option
               Agreement by and between Parent and such Rolling Securityholder
               dated as of October 2, 1998.

               2. DEFINITIONS. Section 1.1 of the Merger Agreement shall be
amended by inserting the following new defined terms in the appropriate
alphabetical order:

                    "AGGREGATE ROLLED AMOUNT" means the aggregate Rolled Amounts
               of all Rolling Securityholders.

                      "AMENDMENT NO.1" means Amendment No.1 to Agreement and
              Plan of Merger dated as of October 2, 1998 ("Amendment No.1") by
              and among Parent and the individuals set forth therein.


<PAGE>
                    "ROLLED AMOUNT" means, with respect to each Rolling
               Securityholder, the amount equal to the sum of:

              (i)(x) the product obtained when the number of shares of
                     Rolled Common Stock (as defined in Section 1 of Amendment
                     No.1) is multiplied by the Per Share Merger Consideration,
                     minus (y) the amount set forth opposite such Stockholder's
                     name in column G of SCHEDULE I; and

             (ii)      (x) the product obtained when the number of shares of 
                    Common Stock issuable upon the exercise of Rolled Options 
                    (as defined in Section 1 of Amendment No.1) immediately 
                    prior to the Effective Time, whether at or upon the passage
                    of time or the occurrence of future events, is multiplied 
                    by an amount equal to the excess of the Per Share Merger
                    Consideration over the per share exercise price of such
                    Rolled Option, minus (y) the amount set forth opposite such
                    Optionholder's name in column H of SCHEDULE I.

                    "ROLLING SECURITYHOLDER" has the meaning set forth in the
               preamble of Amendment No. 1.

                    "TRANSACTION DOCUMENTS" means the collective reference to
               Amendment No. 1, the Merger Agreement, the Indemnification Escrow
               Agreement and each other agreement, document and instrument
               required to be executed in accordance therewith.

                    3. GENERAL PROVISIONS.

                       (a) FURTHER ASSURANCES. Each party hereto shall do and
perform or cause to be done and performed all such further acts and things and
shall execute and deliver all such other agreements, certificates, instruments
and documents as any other party hereto reasonably may request in order to carry
out the intent and accomplish the purposes of this Agreement.

                       (b) AMENDMENT. This Agreement may not be amended or
supplemented except by an instrument or counterparts thereof in writing signed
by the parties to be bound thereby. The Merger Agreement, as amended hereby, is
hereby ratified and confirmed in all respects and shall continue in full force
and effect.

                       (c) SEVERABILITY. If any term or other provision of this
Agreement is invalid, illegal, or incapable of being enforced by any rule of
applicable law, or public policy, all other conditions and provisions of this
Agreement shall


<PAGE>

nevertheless remain in full force and effect. The parties further agree that any
court of competent jurisdiction is expressly authorized to modify any such
unenforceable provision of this Agreement in lieu of severing such unenforceable
provision from this Agreement in its entirety, whether by rewriting the
offending provision, deleting any or all of the offending provision, adding
additional language to this Agreement, or by making such other modifications as
it deems warranted to carry out the intent and agreement of the parties as
embodied herein to the maximum extent permitted by law. The parties expressly
agree that this Agreement as so modified by a court of competent jurisdiction
shall be binding upon and enforceable against each of them.

                       (d) PARTIES IN INTEREST. This Agreement shall be binding
upon and inure solely to the benefit of such party hereto and their permitted
successors and assigns. Nothing in this Agreement is intended to confer upon any
other person any rights or remedies of any nature whatsoever under or by reason
of this Agreement except as expressly set forth herein. Neither this Agreement
nor any rights, interests or obligations hereunder may be assigned by any
Withholding Stockholder without the prior written consent of the Parent.

                       (e) COUNTERPARTS. This Agreement may be executed and
delivered (including by facsimile transmission) in one or more counterparts, all
of which shall be considered one and the same agreement and shall become
effective when one or more counterparts have been signed by each of the parties
and delivered to the other parties, it being understood that all parties need
not sign the same counterpart.

                       (f) ENTIRE AGREEMENT. This Agreement (and the schedules
and exhibits hereto), the Merger Agreement (which term shall be deemed to
include the exhibits and schedules thereto and the other certificates, documents
and instruments delivered thereunder) and the Confidentiality Agreement
constitute the entire agreement of the parties hereto, and supersede all prior
agreements, letters of intent and understand ings, both written and oral, among
the parties with respect to the subject matter hereof.

                       (g) GOVERNING LAW. This Agreement shall be governed by
and construed in accordance with the laws of the State of Delaware without
giving effect to any conflicts of law provisions.

                       (h) ASSIGNMENT. Neither this Agreement nor any of the
rights, interests, or obligations hereunder shall be assigned by any of the
parties hereto, whether by operation of law or otherwise; provided, however,
that upon notice to the Company and the Representative and without releasing
Parent from any of their respective obligations or liabilities hereunder, Parent
may assign or delegate any or all of its rights 


<PAGE>

or obligations under this Agreement to any Affiliate of Parent. In the event of
such an assignment, the provisions of this Agreement shall inure to the benefit
of and be binding on the assigns of Parent. Any attempted assignment in
violation of this Section shall be null and void.

                       (i) HEADINGS. The headings of this Agreement are for
convenience of reference only and are not part of the substance of this
Agreement.

                       (j) EXHIBITS. All Exhibits referred to in this Agreement
are intended to be and are hereby specifically made a part of this Agreement.


<PAGE>

                       IN WITNESS WHEREOF, the parties hereto have executed and
delivered this Agreement as of the date and year first above written.


                                  D AND W HOLDINGS, INC.


                                  By: ___________________________________
                                         Name:
                                         Title:


                                  ROLLING SECURITYHOLDERS


                                  ---------------------------------------
                                  Jill Anderson

                                  ---------------------------------------
                                  Al Ashe

                                  ---------------------------------------
                                  Ed Beachley

                                  ---------------------------------------
                                  Fred Bengston

                                  ---------------------------------------
                                  Tom Bowen

                                  ---------------------------------------
                                  Martin Cook

                                  ---------------------------------------
                                  John Craine

                                  ---------------------------------------
                                  Bob Deakin

                                  ---------------------------------------
                                  Mike Easterly


<PAGE>

                                ---------------------------------------
                                Randall Fojtasek

                                ---------------------------------------
                                Russell Fojtasek

                                ---------------------------------------
                                George Frost

                                --------------------------------------- 
                                James Gresham

                                ---------------------------------------
                                Horace Hicks

                                ---------------------------------------
                                Mike Hillmeyer

                                ---------------------------------------
                                Rich Kettle

                                ---------------------------------------
                                Jeff Hull

                                ---------------------------------------
                                Tom LaManna

                                ---------------------------------------
                                Eric Long

                                ---------------------------------------
                                Scott McGill

                                ---------------------------------------
                                Jim McGlinn

                                ---------------------------------------
                                Dow Pointer

                                ---------------------------------------
                                Jamey Renfrow


<PAGE>

                                ---------------------------------------
                                Billy Robinson

                                ---------------------------------------
                                Lou Simi

                                ---------------------------------------
                                Jim Wright

                                ---------------------------------------
                                Pete Ziegler


<PAGE>

                                    EXHIBIT A
                                    ---------

                   Name
                   ----
                   Beachley                                28,261
                   Bengston                                 4,348
                   Bowen                                    4,348
                   Craine                                   6,522
                   Deakin                                   2,174
                   Easterly                                 2,174
                   Kettle                                  13,913
                   McGlinn                                  6,522
                   Wright                                   5,217
                                     TOTAL:                73,479


<PAGE>

                                    EXHIBIT B
                                    ---------

                   Name
                   ----
                   Anderson                                   10,870
                   --------                                   ------
                   Ashe                                          870
                   ----                                          ---
                   Beachley                                   15,217
                   --------                                   ------
                   Bengston                                   39,130
                   --------                                   ------
                   Bowen                                       6,522
                   -----                                       -----
                   Cook                                        1,739
                   ----                                        -----
                   Craine                                     15,217
                   ------                                     ------
                   Deakin                                     19,565
                   ------                                     ------
                   Easterly                                   19,565
                   --------                                   ------
                   Randall Fojtasek                          434,783 (1)
                   ----------------                          -------
                   Russell Fojtasek                           43,478
                   Frost                                      43,478
                   Gresham                                    10,870
                   Horace Hicks                               43,478
                   Hillmeyer                                  43,478
                   Hull                                       54,348
                   Kettle                                      7,826
                   LaManna                                       435
                   Long                                       10,870
                   McGill                                        435
                   McGlinn                                    26,087
                   Pointer                                    32,609
                   Renfrow                                     4,348
                   Robinson                                  108,696
                   Simi                                      108,696
                   Wright                                     16,522
                   Ziegler                                       435
                                           TOTAL:          1,119,567

------------------------

(1)  Randall Fojtasek is converting warrants, as opposed to options, at the same
     ratio.