Exhibit 21
SUBSIDIARIES OF SUMMIT MATERIALS, INC.
SUBSIDIARIES OF SUMMIT MATERIALS, LLC
(as of February 16, 2023)
NameJurisdiction of Incorporation or Organization
Alan Ritchey Materials Company, L.C.Oklahoma
Alleyton Resource Company, LLCDelaware
Alleyton Services Company, LLCDelaware
American Materials Company, LLCNorth Carolina
AMI Associates, LCUtah
Asphalt Materials, LLCUtah
Austin Materials, LLCDelaware
B&B Resources, Inc.Utah
Boxley Materials CompanyVirginia
Buckingham Slate Company, LLCVirginia
Buckingham Slate #1, LLCVirginia
Buckingham Slate #2, LLCVirginia
Buildex, LLCDelaware
Colorado County Sand & Gravel Co., L.L.C.Texas
Columbia Aggregates, LLCSouth Carolina
Con-Agg Companies, LLCMissouri
Concrete Supply of Topeka, LLCKansas
Continental Cement Company, L.L.C.Delaware
Cornejo & Sons, L.L.C.Kansas
Elam Construction, Inc.Colorado
Florida Stone Products, LLCDelaware
Georgia Stone Products, LLCGeorgia
Glasscock Company, Inc.South Carolina
Glasscock Logistics Company, LLCSouth Carolina
Green America Recycling, LLCMissouri
Hamm, Inc.Kansas
H.C. Rustin CorporationOklahoma
Industrial Asphalt, LLCTexas
Jefferson Quarry, LLCGeorgia
Kilgore Companies, LLCDelaware
Kilgore Partners, L.P.Utah
Lanier Construction Company, LLC
South Carolina
Laredo Paving, Inc.Texas
LeGrand Johnson Construction Co.Utah
Lewis & Lewis, Inc.Wyoming
Mainland Construction Materials ULCBritish Columbia
Metro Ready Mix, L.L.C.Utah
Mid-Missouri Limestone, LLCMissouri
Multisource Sand and Gravel Co., Ltd.
Texas
N.R. Hamm Contractor, LLCKansas



N.R. Hamm Quarry, LLCKansas
Northwest Aggregates, Inc.Colorado
Northwest Ready Mix, Inc.Colorado
Peak Materials, LLCDelaware
Peak Ready Mix, LLCNew Mexico
Penny’s Concrete and Ready Mix, L.L.C.Kansas
Price Construction, Ltd.Texas
RK Hall, LLCDelaware
SAGE, L.L.C.Texas
SCS Materials, LLCTexas
Sierra Ready Mix Limited Liability CompanyNevada
Stoner Sand, L.L.C.Missouri
Summit Finance Group, LLCDelaware
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, LLCDelaware
Summit Materials, LLC(1)Delaware
Troy Vines, Inc.Texas
Valley Real Estate Holdings, LLCVirginia
Walker Sand & Gravel Ltd. Co.Idaho
XIT Sand and Gravel, LLCTexas
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(1) Subsidiary of Summit Materials, Inc. but not of Summit Materials, LLC.