“When the construction of an administrative regulation rather than a statute is in issue, deference is even more clearly in order.” 1330 Connecticut Ave. Inc. v. District of Columbia Zoning Comm'n, 669 A.2d 708, 714–15 (D.C.1995) (internal quotation marks omitted); see Schonberger v. District of Columbia Bd. of Zoning Adjustment, 940 A.2d 159, 162 (D.C.2008) (deferring to agency interpretation where regulations were ambiguous or silent). That deference is based on “the agency's presumed expertise in construing the statute it administers.” United States Parole Comm'n v. Noble, 693 A.2d 1084, 1096 (D.C.1997), adopted on reh'g, 711 A.2d 85 (D.C.1998) (en banc).

Ordinarily, the building permit is the document that reflects a zoning decision about whether a proposed structure, and its intended use as described in the permit application, conform to the zoning regulations. See Schonberger v. District of Columbia Bd. of Zoning Adjustment, 940 A.2d 159, 161 n. 2 (D.C. 2008) (describing the BZA's determination that a building permit "contained the relevant zoning decision"); Rodgers Bros. Custodial Servs. v. District of Columbia Bd. of Zoning Adjustment, 846 A.2d 308, 316 (D.C. 2004) ("Ordinarily municipalities look to a building permit accompanied by an application and building plans to ensure consistency with zoning regulations," citing ANDERSON'S LAW OF ZONING (4th ed. 1996, at 362));Sisson, 805 A.2d at 968 (quoting the BZA's observation that "the [building] permits for the garage should not have been issued if the garage did not provide access in conformance with the zoning regulations"); Woodley Park Cmty. Ass'n v. District of Columbia Bd. of Zoning Adjustment, 490 A.2d 628, 637-38 (D.C. 1985) (reasoning that because building permit had earlier resolved issues as to height, setback and use, these decisions could not be challenged through an appeal of the certificate of occupancy); see also 11 DCMR § 3202.1 (providing generally that "a building permit