EXHIBIT 5.1

July 16, 2004


Headwaters Incorporated
10653 South River Front Parkway, Suite 300
South Jordan, UT 84095

     Re:  Registration Statement on Form S-3

Ladies and Gentlemen:

We are acting as counsel for Headwaters Incorporated, a Delaware corporation
(the "Company"), in connection with the Registration Statement on Form S-3 (the
"Registration Statement") relating to the registration under the Securities Act
of 1933 (the "Act") of $172,500,000 aggregate principal amount of 2?%
Convertible Senior Subordinated Notes due 2016 (the "Securities") and the shares
of Common Stock, par value $0.001 per share (the "Common Stock"), of the Company
initially issuable upon conversion of the Securities (the "Conversion Shares").
The Securities were issued pursuant to an Indenture dated as of June 1, 2004
between the Company and Wells Fargo Bank N.A., as Trustee (the "Indenture"). The
Securities and the Conversion Shares are to be offered for the respective
accounts of the holders thereof.

We have reviewed and are familiar with such corporate proceedings and other
matters as we have deemed necessary for this opinion. In rendering this opinion,
we have assumed that the Indenture has been duly authorized, executed and
delivered by the Trustee, the Securities have been properly authenticated by the
manual signature of an authorized representative of the Trustee, and the
signatures on all documents examined by us are genuine, which assumptions we
have not independently verified. Based upon the foregoing, we are of the opinion
that (i) the Securities have been duly authorized and are valid and legally
binding obligations of the Company, enforceable against the Company in
accordance with their terms, and entitled to the benefits of the Indenture,
except as may be limited by applicable bankruptcy, insolvency, reorganization,
moratorium, fraudulent transfer and similar laws affecting or relating to the
rights of creditors generally, by general principles of equity (regardless of
whether considered in a proceeding in equity or at law), and by requirements of
reasonableness, good faith and fair dealing, and (ii) the Conversion Shares have
been duly authorized and, when issued by the Company upon conversion of the
Securities in accordance with the Indenture, will be legally issued, fully paid
and nonassessable.

This opinion is limited to matters governed by the General Corporation Law of
the State of Delaware and the laws of the State of New York.

We hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement and to the use of our name under the caption "Legal
Matters" in the Registration Statement and in the Prospectus included therein.
In giving this consent, we do not thereby admit that we are within the category
of persons whose consent is required under Section 7 of the Act or the rules and
regulations of the Securities and Exchange Commission promulgated thereunder.

Very truly yours,

/s/ Pillsbury Winthrop LLP