<PAGE>
                                                                     EXHIBIT 2.5

                          AGREEMENT AND PLAN OF MERGER

         THIS AGREEMENT AND PLAN OF MERGER, dated this 27th day of December,
2001 (this "Agreement and Plan of Merger"), is made by and between Atrium
Companies, Inc., a Delaware corporation ("Atrium" or the "Surviving
Corporation") and Door Holdings, Inc., a Delaware corporation ("Door Holdings"
or the "Non-Surviving Corporation").

                                    RECITALS

         WHEREAS, the parties desire to streamline their operations, minimize
tax obligations, and reduce the overall costs of doing business by consolidating
operations into one corporate entity (the "Merger");

         WHEREAS, to effect these objectives, and upon the terms and subject to
the conditions of this Agreement and Plan of Merger and in accordance with the
Delaware General Corporation Law (the "DGCL"), Door Holdings proposes to merge
with and into Atrium, with Atrium being the surviving entity;

         WHEREAS, the parties intend for federal income tax purposes that the
Merger shall qualify for treatment under Section 332(a) of the Internal Revenue
Code of 1986, as amended, (the "Code"), Section 337(a) of the Code and Section
368(a) of the Code; and

         WHEREAS, the Boards of Directors of Atrium and Door Holdings have
adopted resolutions approving this Agreement and Plan of Merger and the
transactions contemplated hereunder.

         NOW, THEREFORE, to effect the Merger and in consideration of the
premises and the mutual covenants and agreements contained herein, the parties
hereby provide for the following terms and conditions of the Merger:

1.       Merger

         On the Effective Date (as defined in Section 10) and subject to the
terms and conditions of this Agreement and Plan of Merger, Door Holdings shall
be merged with and into Atrium, which latter corporation shall be the surviving
corporation in the Merger. The corporate existence of Atrium with all of its
purposes, powers and objects, shall continue unaffected and unimpaired by the
Merger.

         As of the Effective Date, the separate corporate existence of Door
Holdings shall cease and thereupon Atrium and Door Holdings shall be a single
corporation, to wit, Atrium, as the Surviving Corporation, shall be governed by
the laws of the State of Delaware.

2.       Vesting of Assets and Liabilities of the Non-Surviving Corporation in
         Surviving Corporation

         On the Effective Date, all rights, immunities, privileges, powers and
franchises of the Non-Surviving Corporation, all property, real, personal and
mixed, tangible and intangible, all debts due on accounts, and all causes of
action and rights to bring an action belonging to the


<PAGE>


Non-Surviving Corporation shall vest in the Surviving Corporation without
further act or deed as they were vested in the Non-Surviving Corporation, and
the title to any real estate, whether vested by deed or otherwise, or a
leasehold interest in real estate, shall not revert or be in any way impaired by
reason of the Merger; and the Surviving Corporation shall thenceforth assume and
be responsible for all such debts, liabilities, obligations and duties of the
Non-Surviving Corporation and all such debts, liabilities, obligations and
duties shall thenceforth attach to the Surviving Corporation and may be enforced
against it to the same extent as if such debts, liabilities, obligations and
duties had been incurred or contracted by the Surviving Corporation.

         The liabilities existing on the Effective Date of the Non-Surviving
Corporation or of its directors or officers shall not be affected, nor shall the
rights of creditors thereof or of any person dealing with the Non-Surviving
Corporation, or any liens upon the property of the Non-Surviving Corporation, be
impaired by the Merger, and all rights of creditors and all liens upon the
property of the Non-Surviving Corporation shall be preserved unimpaired, and any
action or proceeding pending by or against the Non-Surviving Corporation may be
prosecuted to judgment the same as if the Merger had not taken place, which
judgment shall bind the Surviving Corporation, or the Surviving Corporation may
be proceeded against or substituted in its place.

         If at any time after the Effective Date, the Surviving Corporation
shall consider or be advised that any further assignments or instruments are
necessary or desirable to vest, perfect or confirm in it the title to any assets
or rights of the Non-Surviving Corporation acquired or to be acquired by reason
of, or as a result of, the Merger, the Non-Surviving Corporation and its
officers and directors shall and will execute and deliver all such deeds,
assignments and instruments and do all things necessary or proper to vest,
perfect or confirm title to such assets or rights in the Surviving Corporation
and otherwise to carry out the purpose of this Agreement and Plan of Merger, and
the officers and directors of the Non-Surviving Corporation and the officers and
directors of the Surviving Corporation are fully authorized in the name of the
Non-Surviving Corporation and the Surviving Corporation to take any and all such
action.

3.       Name

         The name of the surviving corporation in the Merger shall be Atrium
Companies, Inc.

4.       Certificate of Incorporation

         The Certificate of Incorporation of Atrium, including any amendments
thereto, as in effect immediately prior to the Effective Date, shall be the
Certificate of Incorporation of the Surviving Corporation and thereafter shall
continue to be its Certificate of Incorporation (until amended as provided
therein under the DGCL).

5.       By-Laws

         The By-Laws of Atrium, including any amendments thereto, as in effect
immediately prior to the Effective Date, shall be the By-Laws of the Surviving
Corporation and thereafter shall continue to be its By-Laws (until amended as
provided therein and under the DGCL).


                                       2
<PAGE>


6.       Directors of the Surviving Corporation

         Those persons serving as members of the Board of Directors of Atrium on
the Effective Date shall be members of the Board of Directors of the Surviving
Corporation and shall hold office until their respective successors are duly
elected or appointed, or their earlier death, resignation or removal in
accordance with the Certificate of Incorporation and the By-laws of the
Surviving Corporation. Those persons serving as members of the Board of
Directors of the Non-Surviving Corporation immediately prior to the Effective
Date shall cease serving as such members as of the Effective Date.

7.       Officers

         All persons holding office in Atrium on the Effective Date shall be
officers of the Surviving Corporation, and shall hold office in the same
capacities and with the same titles, powers and responsibilities, subject to the
By-Laws of the Surviving Corporation, from the Effective Date and for the same
term and subject to the same conditions as such offices were held in Atrium
immediately prior to the Effective Date. Those persons serving as officers of
the Non-Surviving Corporation immediately prior to the Effective Date shall
cease holding their respective offices as of the Effective Date.

8.       Cancellation of Shares

         On the Effective Date, by virtue of the Merger and without any further
action on the part of either Door Holdings or Atrium or their respective
stockholders, each share of stock of Door Holdings shall be canceled and the
certificates representing such shares surrendered to the Secretary of the
Surviving Corporation.

9.       Atrium Shares

         Each share of stock of Atrium shall remain in full force and effect and
shall not be canceled or surrendered.

10.      Effective Date of the Merger

                  Subject to the provisions of this Agreement and Plan of
Merger, the parties hereto shall cause the Merger to be completed by filing all
appropriate certificates and instruments, including, without limitation, a
certificate of merger (the "Certificate of Merger") in accordance with
applicable law, and the Merger shall become effective upon the filing of the
Certificate of Merger with the Secretary of State of the State of Delaware (the
"Effective Date").

11.      Assets, Liabilities, Reserves, and Accounts

         Upon the Effective Date, the assets, liabilities, reserves, and
accounts of the Non-Surviving Corporation shall be taken upon the books of the
Surviving Corporation at the amounts at which they would have been carried on
the books of the Non-Surviving Corporation, subject to such adjustments or
eliminations of intercompany items, if any, as may be appropriate in giving
effect to the Merger.


                                       3
<PAGE>


12.      Corporate Acts and Employees of Non-Surviving Corporation

         All corporate acts, plans, policies, approvals and authorizations of
the Non-Surviving Corporation, its stockholders, Board of Directors, committees
of the Board of Directors, officers and agents, which were valid and effective
immediately prior to the Effective Date shall be taken for all purposes as the
acts, plans, policies, approvals, and authorizations of the Surviving
Corporation, and shall be as effective and binding thereon as the same were with
respect to the Non-Surviving Corporation. The employees and agents of the
Non-Surviving Corporation shall become the employees and agents of the Surviving
Corporation, and continue to be entitled to the same rights and benefits, and
subject to the same obligations and responsibilities, which they had as
employees and agents of the Non-Surviving Corporation.

13.      Termination

         This Agreement and Plan of Merger may be terminated and abandoned by
resolutions of the Board of Directors of either Door Holdings or Atrium at any
time prior to the Effective Date if circumstances develop which in the opinion
of either such Board of Directors make proceeding with the Merger inadvisable.
In the event of the termination and abandonment of this Agreement and Plan of
Merger and the Merger pursuant to the foregoing sentence of this Section 13,
this Agreement shall become void and have no effect, without any liability on
the part of Door Holdings and Atrium, their stockholders, directors or officers
in respect thereof.

14.      Representations and Warranties

         (a) Atrium represents and warrants to Door Holdings as follows:

             (i) Atrium is a corporation duly organized, validly existing and in
good standing under the laws of the State of Delaware.

             (ii) Atrium has all necessary corporate power and authority to
enter into and perform its obligations under this Agreement and Plan of Merger
and the transactions contemplated hereby, and Atrium's execution, delivery and
performance of this Agreement and Plan of Merger have been duly and validly
authorized by all necessary action on its part. This Agreement and Plan of
Merger has been duly executed and delivered by Atrium and constitutes its valid
and binding obligation, enforceable against it in accordance with its terms,
except as limited by laws affecting creditors' rights or equitable principles
generally.

             (b) Door Holdings represents and warrants to Atrium as follows:

             (i) Door Holdings is a corporation duly organized, validly existing
and in good standing under the laws of the State of Delaware.

             (ii) Door Holdings has all necessary corporate power and authority
to enter into and perform its obligations under this Agreement and Plan of
Merger and the transactions contemplated hereby, and Door Holding's execution,
delivery and performance of this Agreement and Plan of Merger have been duly and
validly authorized by all necessary action on its part. This Agreement and Plan
of Merger has been duly executed and delivered by Door Holdings and constitutes
its valid and binding obligation, enforceable against it in accordance


                                       4
<PAGE>


with its terms, except as limited by laws affecting creditors' rights or
equitable principles generally.

15.      Governing Law

         This Agreement and Plan of Merger shall be governed by and construed in
accordance with the laws of the State of Delaware, without giving effect to
choice of law principles thereof.

16.      No Rights or Remedies in Third Parties

         Except as otherwise expressly provided in this Agreement and Plan of
Merger, nothing herein is intended, or shall be construed, to confer upon or to
give any person, firm or corporation other than Door Holdings and Atrium and
their respective stockholders any rights or remedies under or by reason of this
Agreement and Plan of Merger.

17.      Counterparts

         This Agreement and Plan of Merger may be executed in any number of
counterparts, each of which shall be deemed to be an original instrument, but
all of which together shall constitute one and the same instrument.

18.      Entire Agreement

         This Agreement and Plan of Merger constitutes the entire agreement
between the parties, and supersedes all prior agreements, written or oral,
between Door Holdings and Atrium as of the date of execution hereof.

19.      Severability

         In case any one or more of the provisions contained in this Agreement
and Plan of Merger shall for any reason be held to be invalid, illegal or
unenforceable in any respect, such invalidity, illegality or unenforceability
shall not affect any other provision hereof and this Agreement and Plan of
Merger shall be construed as if such invalid, illegal or unenforceable provision
had never been contained herein and, in lieu of each such illegal, invalid or
unenforceable provision, there shall be added as a part of this Agreement and
Plan of Merger, a provision as similar in terms to such illegal, invalid or
unenforceable provision as may be possible and be legal, valid and enforceable.

20.      Filing of Required Documents

         The parties each hereby agree to execute, deliver and file such other
documents and instruments and take such other actions as may reasonably be
requested by the other parties in order to more effectively consummate the
transactions contemplated hereby.


                                       5
<PAGE>


         IN WITNESS WHEREOF, this Agreement and Plan of Merger has been executed
on the day and year first above written.



                                        ATRIUM COMPANIES, INC., a Delaware
                                        corporation


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

                                        DOOR HOLDINGS, INC., a Delaware
                                        corporation


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


                                       6
<PAGE>


                             SECRETARY'S CERTIFICATE

                                State of Delaware

         The undersigned hereby certifies that he is the duly elected Secretary
Atrium Companies, Inc. a Delaware corporation, and that the foregoing is a true
and correct copy of the Agreement and Plan of Merger executed on the ___ day of
December, 2001, by the duly authorized officer of Atrium Companies, Inc.




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

Name:
Secretary


                                       7
<PAGE>


                             SECRETARY'S CERTIFICATE

                                State of Delaware

         The undersigned hereby certifies that he is the duly elected Secretary
of Door Holdings, Inc., a Delaware corporation, and that the foregoing is a true
and correct copy of the Agreement and Plan of Merger executed on the ___ day of
December, 2001, by the duly authorized officer of Door Holdings, Inc.




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

Name:
Secretary


                                       8