Morris Communications Company d/b/a Fairway Outdoor Advertising (“Fairway”) appeals from an order affirming the decision of the City of Bessemer City Zoning Board of Adjustment’s (“the BOA”) decision requiring the removal of petitioner’s billboard. We affirm.
Fairway leases a parcel of land (“the property”) in Bessemer City, North Carolina (“the City”), for the purpose of using and maintaining a billboard (“the billboard”). Prior to July 2005, the billboard was lawfully erected on the property. In July 2005, the North Carolina Department of Transportation (“NCDOT”) condemned a portion of the property for a road widening project (“the project”). As a result of the condemnation, Fairway was required to move the billboard to another part of the property.
In order to relocate the billboard, Fairway applied to the City for a sign permit (“the sign permit”). The sign permit was issued on 31 August 2005 and indicated an “Expire Date” of 27 February 2006. By the terms of § 155.207 of the City’s Zoning Ordinance (“the Ordinance”),
[i]f the work described in any compliance or sign permit has not begun within six months from the date of issuance thereof, the permit shall expire. Upon beginning a project, work must be diligently continued until completion with some progress being apparent every three months. If such continuance or work is not shown, the permit will expire.
On 21 November 2005, Fairway applied to Gaston County for a building permit (“the building permit”). The building permit was issued on 13 December 20051 and contained, inter alia, the following language: “This permit becomes null and void if work or construction *634authorized is not commenced within 6 months, or if construction or work is suspended, or abandoned for a period of 1 year at any time after work is started.” The building permit additionally informs the permit holder that “[granting of a permit does not presume to give authority to violate or cancel the provisions of any other state or local law regulating construction or the performance of construction." (Emphasis added).
On 8 June 2006, Gaston County renewed the building permit (“the renewed permit”) until 8 December 2006. On 12 June 2006, the City passed an amendment to the Ordinance (“the amendment”) that banned billboards in the City. With the adoption of the amendment, the billboard became a nonconforming sign.
On 13 June 2006, Fairway took down the billboard in anticipation of the project. After the project was completed, Fairway relocated the billboard in its new location on 6 December 2006. Except for the footings, the billboard was the same sign that had been previously taken down by Fairway before the project began.
On 16 January 2007, the City sent Fairway a Notice of Violation (“the NOV”) regarding the billboard. According to the City, the relocation of the billboard violated the amendment. The NOV also stated that Fairway’s sign permit had expired and that the renewed permit was void as a result. Fairway appealed the NOV to the BOA, which affirmed the NOV on 7 May 2007 and entered a written order requiring the billboard’s removal.
On 10 August 2007, the superior court of Gaston County, by consent of the parties, issued a Writ of Certiorari in order to review the BOA’s decision. On 31 October 2008, the superior court entered an order and judgment affirming the decision of the BOA. Fairway appeals.2
II. Standard of Review
Upon reviewing a decision by a board of adjustment, the superior court’s scope of review includes: (1) Reviewing the record for *635errors in law, (2) Insuring that procedures specified by law in both statute and ordinance are followed, (3) Insuring that appropriate due process rights of a petitioner are protected including the right to offer evidence, cross-examine witnesses, and inspect documents, (4) Insuring that decisions of town boards are supported by competent, material and substantial evidence in the whole record, and (5) Insuring that decisions are not arbitrary and capricious. Depending upon the nature of the alleged error, the superior court must apply one of two standards of review in an administrative appeal of a decision by a board of adjustment. Where the petitioner asserts that the board’s decision is based on an error of law, de novo review is proper. If the petitioner contends that the board’s decision is arbitrary or capricious, or is unsupported by the evidence, the court applies the whole record test.
E. Outdoor, Inc. v. Bd. of Adjust. of Johnston Cty., 150 N.C. App. 516, 518, 564 S.E.2d 78, 79-80 (2002) (internal quotations and citations omitted). “When this Court reviews such appeals from the superior court, our review is limited to determining whether (1) the superior court determined the appropriate scope of review and (2) whether the superior court, after determining the proper scope of review, properly applied such a standard.” Id. at 518, 564 S.E.2d at 80.
III. De novo Review
 Fairway argues that the superior court erred in finding that the BOA’s interpretation of the Ordinance is entitled to some deference under a de novo standard of review. We disagree.
In its order, the superior court stated: “In interpreting the applicable ordinances, the [BOA]’s decision is entitled to some deference so long as [the BOA] did not act arbitrarily, oppressively, manifestly abuse its authority, or commit an error of law.” Fairway contends that this deference is inconsistent with a de novo review.
Where the petitioner alleges that a board decision is based on error of law, the reviewing court must examine the record de novo, as though the issue had not yet been determined. However, one of the functions of a Board of Adjustment is to interpret local zoning ordinances, and [the BOA]’s interpretation of its own ordinance is given deference. Therefore, our'task on appeal is not to decide whether another interpretation of the ordinance might reasonably have been reached by the board, but to *636decide if the board acted arbitrarily, oppressively, manifestly abused its authority, or committed an error of law in interpreting the ordinance.
Whiteco Outdoor Adver. v. Johnston Cty. Bd. of Adjust., 132 N.C. App. 465, 470, 513 S.E.2d 70, 74 (1999) (internal quotations and citations omitted). The standard of review included in the superior court’s order is clearly consistent with the standard of review for interpretation of a local zoning ordinance as established by this Court. This assignment of error is overruled.
IV. Validity of Building Permit
 Fairway argues that the superior court erred by concluding that the billboard was in violation of the amendment because Fairway possessed an unexpired and unrevoked building permit from Gaston County. We disagree.
After the amendment, the Ordinance § 155.163(A) stated, in relevant part:
No sign shall hereafter be erected, attached to, suspended from, or supported on a building or structure; nor shall any existing sign be enlarged, relocated, or otherwise altered; nor shall any building permit be issued for such purposes until a sign permit for same has been issued by the Zoning Administrator ....
(Emphasis added). In the instant case, the parties agree a valid sign permit was issued to Fairway on 31 August 2005. The parties do not agree on whether that permit was still in effect when Fairway renewed its building permit in June 2006.
The validity of Fairway’s sign permit at the time it obtained the renewed permit is a mixed question of law and fact. The BOA’s statutory interpretation of “work” in the Ordinance is a question of law reviewed under the standard articulated in Whiteco. Whether Fairway’s action constituted “work” as defined by the Ordinance is a question of fact that is reviewed using the whole record test.
A. Definition of work
Under § 155.207 of the Ordinance, “[i]f the work described in any compliance or sign permit has not begun within six months from the date of issuance thereof, the permit shall expire.” The BOA concluded that Fairway did not commence any “work” on the billboard in the six *637months after the sign permit was issued on 31 August 2005 and therefore the sign permit was expired at the time Fairway attempted to renew the building permit.
Kevin Krouse, the City Zoning Administrator (“Krouse”), testified that he saw no signs of work on the property until December 2006, long after the sign permit would have expired by its terms. Krouse defined “work” as “actually something moving on the ground . . . [construction.” The BOA affirmed the opinion of Krouse and ordered the billboard removed.
Fairway argues that the BOA should not have relied upon the definition of “work” offered by Krouse. As previously noted, this Court gives the BOA’s interpretation of its own ordinance deference. CG&T Corp. v. Bd. of Adjust. of Wilmington, 105 N.C. App. 32, 39, 411 S.E.2d 655, 659 (1992). We need not decide whether another interpretation of the ordinance might reasonably have been reached by the BOA. Whiteco, 132 N.C. App. at 470, 513 S.E.2d at 74.
“When statutory language is clear and unambiguous, [w]ords in a statute must be construed in accordance with their plain meaning unless the statute provides an alternative meaning.” Procter v. City of Raleigh Bd. of Adjust., 140 N.C. App. 784, 785-86, 538 S.E.2d 621, 622 (2000) (internal quotations and citation omitted). The Ordinance itself does not define “work.” However, the Ordinance § 155.163 requires a sign permit to be issued any time a sign is “erected, attached to, suspended from, or supported on a building or structure” or when an existing sign is “enlarged, relocated, or otherwise altered.” Since the purpose of a sign permit is to allow the construction or physical alteration of a sign, it does not appear that the BOA’s definition of “work” for the purposes of maintaining a valid sign permit, “something moving on the ground . . . [construction,” is an unreasonable interpretation or otherwise the result of an error of law.
B. Fairway’s “work”
Using the BOA’s definition of “work,” we must now determine whether the BOA properly concluded that Fairway’s actions did not constitute “work.” This determination requires the use of the whole record test.
This test requires the reviewing court to examine all competent evidence (the ‘whole record’) in order to determine whether the [Board’s] decision is supported by substantial evidence. *638Substantial evidence is such relevant evidence as a reasonable mind might accept as adequate to support a conclusion. The reviewing court should not replace the [Board’s] judgment as between two reasonably conflicting views; [w]hile the record may contain evidence contrary to the findings of the [Board], this Court may not substitute its judgment for that of the [Board].
Coucoulas/Knight Props., LLC v. Town of Hillsborough, — N.C. App.-,-, 683 S.E.2d 228, 230 (2009) (citation omitted).
In the instant case, there is sufficient evidence in the whole record to support the BOA’s decision. Fairway does not dispute that there was no physical construction on the site during the six months after issuance of the sign permit. Fairway presented evidence that it conducted negotiations with NCDOT and the owner of the property regarding where it would move the billboard, but at the same time admitted that it did not inform the City of these ongoing negotiations. Krouse testified that he observed no work on the property until months after the sign permit expired. This is enough evidence “as a reasonable mind might accept as adequate to support a conclusion” and the decision of the BOA should therefore not be disturbed.
V. Vested Rights
 Because the sign permit had expired before Fairway renewed its building permit in June 2006, it could not validly renew its Gaston County building permit under the express terms of the Ordinance § 155.163. The BOA argues that the building permit was therefore void. Fairway argues that until the invalid permit was revoked pursuant to N.C. Gen. Stat. § 160A-422 (2007), it has established statutory vested rights under N.C. Gen. Stat. § 160A-385(b)(i) (2007).
N.C. Gen. Stat. § 160A-422 delineates the procedure for the revocation of permits.
The appropriate inspector may revoke and require the return of any permit by notifying the permit holder in writing stating the reason for the revocation. Permits shall be revoked for any substantial departure from the approved application, plans, or specifications; for refusal or failure to comply with the requirements of any applicable State or local laws; or for false statements or misrepresentations made in securing the permit. Any permit mistakenly issued in violation of an applicable State or local law may also be revoked.
*639N.C. Gen. Stat. § 160A-422 (2007) (emphasis added). The BOA argues that revocation of the renewed permit was unnecessary because it was void ab initio. This interpretation would render the portion of N.C. Gen. Stat. § 160A-422 emphasized above superfluous. “Such statutory construction is not permitted, because a statute must be construed, if possible, to give meaning and effect to all of its provisions.” HCA Crossroads Residential Ctrs. v. North Carolina Dep’t of Human Res., 327 N.C. 573, 578, 398 S.E.2d 466, 470 (1990). Therefore, the proper way to revoke a building permit, even a permit issued in violation of a state or local law, is by following the statutory revocation procedure of N.C. Gen. Stat. § 160A-422.
In the instant case, it is undisputed that Fairway’s building permit was not revoked pursuant to N.C. Gen. Stat. § 160A-422 until after the amendment was passed. Fairway argues that because it possessed an unrevoked building permit at the time of the amendment, it is entitled to vested rights under N.C. Gen. Stat. § 160A-385(b), which states, in relevant part:
Amendments in zoning ordinances shall not be applicable or enforceable without consent of the owner with regard to buildings and uses for which .. . (i) building permits have been issued pursuant to G.S. 160A-417 prior to the enactment of the ordinance making the change or changes so long as the permits remain valid and unexpired pursuant to G.S. 160A-418 and unrevoked pursuant to G.S. 160A-422 ....
N.C. Gen. Stat. § 160A-385(b) (2007) (emphasis added). Although the building permit was not revoked at the time of the amendment, the Gaston County building inspector who issued the renewed permit testified that because Fairway did not possess a valid sign permit, the renewed permit was issued by mistake, contrary to applicable law, and was therefore invalid. An invalid permit does not qualify for statutory rights according to the express language of N.C. Gen. Stat. § 160A-385(b)(i).
This result is also supported by previous holdings of this Court. “Permits unlawfully or mistakenly issued do not create a vested right.” Clark Stone Co. v. N.C. Dep’t of Env’t & Natural Res., 164 N.C. App. 24, 40, 594 S.E.2d 832, 842 (2004); see also Raleigh v. Fisher, 232 N.C. 629, 635, 61 S.E.2d 897, 902 (1950). Thus, Fairway cannot rely upon a mistakenly issued permit to establish vested rights in its nonconforming use of the property. This assignment of error is overruled.
*640VI. Equitable Estoppel
 Fairway argues that the superior court erred in concluding that the City and the BOA were not equitably estopped from ordering the removal of the billboard. We .disagree.
It has been established that the building permit renewal was issued by mistake, contrary to the express terms of the Ordinance. Fairway correctly argues that it relied upon this invalid renewed permit to its detriment. However, in such a situation, our Supreme Court has held, “a municipality cannot be estopped to enforce a zoning ordinance against a violator by the conduct of its officials in encouraging or permitting such violator to violate such ordinance in times past.” Fisher, 232 N.C. at 635, 61 S.E.2d at 902 (citations omitted); see also Helms v. Charlotte, 255 N.C. 647, 652, 122 S.E.2d 817, 821 (1961). The Fisher Court, acknowledging the hardship that this’rule can create, succinctly explained the reasoning behind it:
Undoubtedly this conclusion entails much hardship to the defendants. Nevertheless, the law must be so written; for a contrary decision would require an acceptance of the paradoxical proposition that a citizen can acquire immunity to the law of his country by habitually violating such law with the consent of unfaithful public officials charged with the duty of enforcing it.
VIL Nonconforming Provisions of the Ordinance
 Fairway argues that the superior court erred by failing to conclude that the nonconforming provisions of the Ordinance did not prohibit the relocation of the billboard. We disagree.
As previously noted, § 155.163(A) of the Ordinance provides that:
No sign shall hereafter be erected, attached to, suspended from, or supported on a building or structure; nor shall any existing sign be enlarged, relocated, or otherwise altered; nor shall any building permit be issued for such purposes until a sign permit for same has been issued by the Zoning Administrator. . . .
The parties agree that the billboard was a nonconforming sign after the amendment was passed. By the terms of the Ordinance, structural changes, including relocations, are not permitted, even for conforming uses, without a valid sign permit and a valid building permit. *641Fairway did not possess a valid version of either of these permits at the time it relocated its billboard.
Additionally, § 155.172 of the Ordinance, entitled “Nonconforming Signs,” provides that:
(A) Existing nonconforming sign. A non-conforming sign . . . shall not be replaced by another non-conforming sign except that the substitution or inter-change of poster panels, painted boards, or demount-able material on nonconforming signs shall be permitted. . . .
Therefore, only the interchange of the actual changeable sign sections of a billboard are allowed in order to maintain an existing nonconforming use. The relocation of the billboard by Fairway went well beyond the interchange of sign sections and Fairway could not maintain an existing nonconforming use on this basis. This assignment of error is overruled.
YIII. Whole Record
 Fairway finally argues that the superior court erred in concluding that the BOA’s decision was supported by competent, material, and substantial evidence and was otherwise not arbitrary or capricious. We disagree.
Specifically, Fairway argues that the superior court erred by upholding the BOA’s findings that Fairway had done no “work” to maintain its right to the sign permit and by upholding the BOA’s finding that Fairway possessed no statutory vested rights. These contentions have been previously considered and found to be without merit. There is substantial evidence in the whole record to support the BOA’s findings and its decision was the result of the application of correct legal principles. This assignment of error is overruled.
Judge GEER concurs.
Judge HUNTER, Robert C. dissents by separate opinion.