Exhibit 21

# HEADWATERS INCORPORATED

# Subsidiaries

The ownership of each direct and
indirect subsidiary is 100%, except where indicated below.

Headwaters Construction Materials
Division

| |  | - |  | Headwaters
Construction Materials, Inc., a Utah corporation
| |  | - |  | -----------------------------------------------------------

The
following subsidiaries are part of HCM's block, mortar and stucco group:

| |  | - |  | Headwaters
Construction Materials, LLC (fka HCM Block & Brick, LP), a Texas limited liability company
| |  | - |  | -----------------------------------------------------------------------------------------------------

| |  | - |  | Best
Masonry & Tool Supply, LLC, a Texas limited liability company
| |  | - |  | ------------------------------------------------------------------

| |  | - |  | Don's
Building Supply, LLC, a Texas limited liability company
| |  | - |  | -------------------------------------------------------------

| |  | - |  | HCM
FlexCrete, LLC, a Texas limited liability company
| |  | - |  | -----------------------------------------------------

| |  | - |  | HCM
Utah, Inc., a Utah corporation
| |  | - |  | ----------------------------------

The
following subsidiaries are part of HCM's manufactured architectural stone group:

| |  | - |  | Eldorado
Stone LLC, a Delaware limited liability company
| |  | - |  | --------------------------------------------------------

| |  | - |  | Chihuahua
Stone LLC, a Utah limited liability company
| |  | - |  | -----------------------------------------------------

| |  | - |  | Eldorado
G-Acquisition Co., a Utah corporation
| |  | - |  | ----------------------------------------------

| |  | - |  | Eldorado
SC-Acquisition Co., a Utah corporation
| |  | - |  | -----------------------------------------------

| |  | - |  | Eldorado
Stone Acquisition Co., LLC, a Delaware limited liability company
| |  | - |  | -------------------------------------------------------------------------

| |  | - |  | Eldorado
Stone Funding Co., LLC, a Utah limited liability company
| |  | - |  | -----------------------------------------------------------------

| |  | - |  | Eldorado
Stone Operations LLC, a Utah limited liability company
| |  | - |  | ---------------------------------------------------------------

| |  | - |  | Eldorado
Stone Philippines, Inc., a Philippines corporation
| |  | - |  | -----------------------------------------------------------

| |  | - |  | HCM
Stone, LLC, a Utah limited liability company
| |  | - |  | ------------------------------------------------

| |  | - |  | L-B
Stone LLC, a Utah limited liability company
| |  | - |  | -----------------------------------------------

| |  | - |  | Piedras
Headwaters, S. de R.L. de C.V., a Mexican limited liability company
| |  | - |  | ---------------------------------------------------------------------------

The
following subsidiaries are part of HCM's shutters, siding and tools group:

| |  | - |  | Tapco
International Corporation, a Michigan corporation
| |  | - |  | -------------------------------------------------------

| |  | - |  | Atlantic
Shutter Systems, Inc., a South Carolina corporation
| |  | - |  | ------------------------------------------------------------

| |  | - |  | Metamora
Products Corporation of Elkland, a Pennsylvania corporation
| |  | - |  | --------------------------------------------------------------------

| |  | - |  | Metamora
Products Corporation, a Michigan corporation
| |  | - |  | -----------------------------------------------------

| |  | - |  | MTP,
Inc., an Ohio corporation
| |  | - |  | ------------------------------

| |  | - |  | Tapco
Europe Limited, formed in the United Kingdom
| |  | - |  | --------------------------------------------------

---

Headwaters Energy Services Division

| |  | - |  | Headwaters
Energy Services Corp., a Utah corporation
| |  | - |  | ----------------------------------------------------

| |  | - |  | Blue
Flint Ethanol LLC, a Delaware limited liability company
| |  | - |  | ------------------------------------------------------------

| |  | - |  | Covol
Coal Company, LLC, a Utah limited liability company
| |  | - |  | ---------------------------------------------------------

| |  | - |  | Covol
Engineered Fuels, LC, a Utah limited liability company
| |  | - |  | ------------------------------------------------------------

| |  | - |  | Covol
Services Corporation, a Utah corporation;
| |  | - |  | -----------------------------------------------

| |  | - |  | Environmental
Technologies Group, LLC, a Utah limited liability company
| |  | - |  | -----------------------------------------------------------------------

| |  | - |  | Headwaters
CTL, LLC (fka Hydrocarbon Technologies, Inc.), a Utah limited liability company
| |  | - |  | ------------------------------------------------------------------------------------------

| |  | - |  | Headwaters
Ethanol Operators, LLC, a Utah limited liability company
| |  | - |  | -------------------------------------------------------------------

| |  | - |  | Headwaters
Synfuel Investments, LLC, a Utah limited liability company
| |  | - |  | ---------------------------------------------------------------------

| |  | - |  | HES
Ethanol Holdings, LLC, a Utah limited liability company
| |  | - |  | -----------------------------------------------------------

Headwaters Resources (CCP) Division

| |  | - |  | Headwaters
Resources, Inc., a Utah corporation
| |  | - |  | ----------------------------------------------

| |  | - |  | FlexCrete
Building Systems, LC, a Utah limited liability company, of which HRI is a 90% member
| |  | - |  | ----------------------------------------------------------------------------------------------

| |  | - |  | Florida
N-Viro L.P., a Delaware limited partnership, of which VFL is a 51.5% member
| |  | - |  | -----------------------------------------------------------------------------------

| |  | - |  | Florida
N-Viro Management, LLC, a Delaware limited liability company, of which VFL is a 52%
member
| |  | - |  | --------------------------------------------------------------------------------------------------

| |  | - |  | Headwaters
Resources Limited, formed in New Brunswick, Canada
| |  | - |  | -------------------------------------------------------------

| |  | - |  | Headwaters
Services Corporation, a Utah corporation
| |  | - |  | ---------------------------------------------------

| |  | - |  | VFL
Technology Corporation, a Pennsylvania corporation
| |  | - |  | ------------------------------------------------------

Headwaters Specialty Chemicals
Division

| |  | - |  | Degussa
Headwaters LLP, formed in the United Kingdom, of which Headwaters Incorporated is a 50%
member
| |  | - |  | ------------------------------------------------------------------------------------------------------

| |  | - |  | Degussa
Headwaters Korea Co., Ltd., a Korean limited liability company, of which Headwaters
Incorporated is a 50% member
| |  | - |  | ------------------------------------------------------------------------------------------------------------------------

| |  | - |  | Headwaters
Heavy Oil, LLC, a Utah limited liability company
| |  | - |  | -----------------------------------------------------------

Other Subsidiaries

| |  | - |  | Global
Climate Reserve Corporation, a Utah corporation
| |  | - |  | ------------------------------------------------------

| |  | - |  | Headwaters
Technology Innovation, LLC (fka Headwaters Technology Innovation Group, Inc.), a Utah
limited liability company
| |  | - |  | --------------------------------------------------------------------------------------------------------------------------