Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

Janus International Group, Inc.

Temple, Georgia

We hereby consent to the use in the Prospectus constituting a part of this Registration Statement of our report dated March 22, 2021, relating to the consolidated financial statements of Janus Midco, LLC which is contained in that Prospectus.

We also consent to the reference to us under the caption “Experts” in the Prospectus.

/s/ BDO USA, LLP

Atlanta, Georgia

July 6, 2021

BDO USA, LLP, a Delaware limited liability partnership, is the U.S. member of BDO International Limited, a UK company limited by guarantee, and forms part of the

international BDO network of independent member firms.

BDO is the brand name for the BDO network and for each of the BDO Member Firms.