Exhibit 21
SUBSIDIARIES OF SUMMIT MATERIALS, INC.
SUBSIDIARIES OF SUMMIT MATERIALS, LLC
(as of February 5, 2020)
| Name | Jurisdiction of Incorporation or Organization | |
| Alan Ritchey Materials Company, L.C. | Oklahoma | |
| Alleyton Resource Company, LLC | Delaware | |
| Alleyton Services Company, LLC | Delaware | |
| American Materials Company, LLC | North Carolina | |
| Austin Materials, LLC | Delaware | |
| B&B Resources, Inc. | Utah | |
| Bourbon Limestone Company | Kentucky | |
| Boxley Materials Company | Virginia | |
| Buckingham Slate Company, LLC | Virginia | |
| Buckingham Slate #1, LLC | Virginia | |
| Buckingham Slate #2, LLC | Virginia | |
| Buildex, LLC | Delaware | |
| Colorado County Sand & Gravel Co., L.L.C. | Texas | |
| Columbia Aggregates, LLC | South Carolina | |
| Con-Agg Companies, LLC | Missouri | |
| Concrete Supply of Topeka, LLC | Kansas | |
| Continental Cement Company, L.L.C. | Delaware | |
| Cornejo & Sons, L.L.C. | Kansas | |
| Elam Construction, Inc. | Colorado | |
| Georgia Stone Products, LLC | Georgia | |
| Glasscock Company, Inc. | South Carolina | |
| Glasscock Logistics Company, LLC | South Carolina | |
| Green America Recycling, LLC | Missouri | |
| Hamm, Inc. | Kansas | |
| H.C. Rustin Corporation | Oklahoma | |
| Hinkle Contracting Company LLC | Kentucky | |
| Industrial Asphalt, LLC | Texas | |
| Jefferson Quarry, LLC | Georgia | |
| Kilgore Companies, LLC | Delaware | |
| Kilgore Partners, L.P. | Utah | |
| Laredo Paving, Inc. | Texas | |
| LeGrand Johnson Construction Co. | Utah | |
| Lewis & Lewis, Inc. | Wyoming | |
| Mainland Construction Materials ULC | British Columbia | |
| Metro Ready Mix, L.L.C. | Utah | |
| Mid-Missouri Limestone, LLC | Missouri | |
| N.R. Hamm Contractor, LLC | Kansas | |
| N.R. Hamm Quarry, LLC | Kansas | |
| Northwest Aggregates, Inc. | Colorado | |
| Northwest Ready Mix, Inc. | Colorado | |
| Ohio Valley Asphalt, LLC | Kentucky | |
| Peak Materials, LLC | Delaware | |
| Peak Ready Mix, LLC | New Mexico | |
| Pelican Asphalt Company, LLC | Texas | |
| Penny’s Concrete and Ready Mix, L.L.C. | Kansas | |
| Price Construction, Ltd. | Texas | |
| Razorback Concrete Company | Arkansas | |
| R.D. Johnson Excavating Company, LLC | Kansas | |
| Ready Mix Concrete of Somerset, LLC | Kentucky | |
| RK Hall, LLC | Delaware | |
| SCS Materials, LLC | Texas | |
| Sierra Ready Mix Limited Liability Company | Nevada | |
| Stoner Sand, L.L.C | Missouri | |
| Summit Finance Group, LLC | Delaware | |
| Summit Materials Corporations I, Inc. | Delaware | |
| Summit Materials Finance Corp. | Delaware | |
| Summit Materials Holdings, LLC(1) | Delaware | |
| Summit Materials Holdings L.P.(1) | Delaware | |
| Summit Materials Intermediate Holdings, LLC(1) | Delaware | |
| Summit Materials International, LLC | Delaware | |
| Summit Materials, LLC(1) | Delaware | |
| Troy Vines, Inc. | Texas | |
| Valley Real Estate Holdings, LLC | Virginia | |
| Walker Sand & Gravel Ltd. Co. | Idaho | |
| XIT Sand and Gravel, LLC | Texas | |
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(1) Subsidiary of Summit Materials, Inc. but not of Summit Materials, LLC.