EXHIBIT 3.3

                          CERTIFICATE OF INCORPORATION
                                       OF
                                  ALSIDE, INC.

                  FIRST: The name of the corporation shall be:

                                  ALSIDE, INC.

                  SECOND: The registered office of the corporation in the State
of Delaware shall be located at 100 West Tenth Street in the City of Wilmington,
County of New Castle. The name of the corporation's registered agent at such
address shall be THE CORPORATION TRUST COMPANY.

                  THIRD: The purpose of the corporation shall be to engage in
any part of the world in any capacity in any lawful act or activity for which
corporations may be organized under the General Corporation Law of the State of
Delaware, and the corporation shall be authorized to exercise and enjoy all
powers, rights and privileges conferred upon corporations by the laws of the
State of Delaware, including without limitation all powers necessary or
appropriate to carry out all those acts and activities in which it may lawfully
engage.

                  FOURTH: The capital stock which the corporation shall have the
authority to issue shall consist of 1,000 shares of Common Stock with no par
value. Each issued and outstanding share of Common Stock shall entitle the
holder thereof to one vote per share in respect of any required or permitted
vote by the holders of the Common Stock.

                  FIFTH: The name and mailing address of the incorporator of the
corporation is as follows:

                           D. R. High            600 Grant Street
                                                 Pittsburgh, PA  15230

The powers of the incorporator of the corporation shall terminate upon the
filing of this Certificate of Incorporation.

                  SIXTH: The number of directors of the corporation shall be
fixed from time to time by the by-laws of the corporation. The names and mailing
addresses of the persons who are to serve as directors of the corporation until
the first annual meeting of stockholders or until their successors are elected
and qualified are as follows:

                           R. E. Hilton           600 Grant Street
                                                  Pittsburgh, PA  15230

                           R. M. Stanton          600 Grant Street
                                                  Pittsburgh, PA  15230

                           D. R. High             600 Grant Street
                                                  Pittsburgh, PA  15230

                  SEVENTH: Except as otherwise provided by law or in the by-laws
of the corporation, no written ballot shall be required for the election of
directors of the corporation, or for any other purpose.

                  EIGHTH: The holders of the Common Stock, and the directors of
the corporation, shall each have the right to make, alter or repeal the by-laws
of the corporation.

                  NINTH: Whenever a compromise or arrangement is proposed
between this corporation and its creditors or any class of them and/or between
this corporation and its stockholders or any class of them, any court of
equitable jurisdiction within the State of Delaware may, on the application in a
summary way of this corporation or of any creditor or stockholder thereof or on
the application of any receiver or receivers appointed for this corporation
under the provisions of Section 291 of Title 8 of the Delaware Code or on the
application of trustees in dissolution or of any receiver or receivers appointed
for this corporation under the provisions of Section 279 of Title 8 of the
Delaware Code order a meeting of the creditors or class of creditors, and/or of
the stockholders or class of stockholders of this corporation, as the case may
be, to be summoned in such manner as the said court directs. If a majority in
number representing three-fourths in value of the creditors or class of
creditors, and/or of the stockholders or class of stockholders of this
corporation, as the case may be, agree to any compromise or arrangement and to
any reorganization of this corporation as consequence of such compromise or
arrangement, the said compromise or arrangement and the said reorganization
shall, if sanctioned by the court to which the said application has been made,
be binding on all the creditors or class of creditors, and/or on all the
stockholders or class of stockholders, of this corporation, as the case may be,
and also on this corporation.

                  THE UNDERSIGNED, being the incorporator hereinbefore named,
for the purpose of forming a corporation pursuant to the General Corporation Law
of the State of Delaware, does make this certificate, hereby declaring and
certifying that the facts herein stated are true, and accordingly has hereunto
set his hand this 27th day of December, 1983.

                                                   /s/ D. R. High
                                          -------------------------------------
                                                        D. R. High

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