This court has been petitioned to overturn, as arbitrary and capricious, an Order of the Board of Zoning Adjustment denying a special exception and, as an alternative, a variance.
The special exception would have permitted in an R-5-C district,1 the extension2 of a nonconforming restaurant use and immediately thereafter the change3 of such use to an office use. The variance4 would have accomplished substantially the same purpose by permitting in the R-5-C district an office use.
Petitioners Norman Bernstein, et al., are the owners of the Chastleton, an apartment house.5 On the first floor of the building there are, in addition to residential apartments, nonconforming adjunct commercial uses which include a beauty salon, drugstore, valet shop and a restaurant-caterer.6
Appurtenant to the space occupied by the restaurant-caterer is an area of approximately 900 square feet which, since 1968, has been occupied by Stanley Smith Security, Inc., and used by that agency for office and security monitoring purposes. It was into this area that petitioners proposed to extend the nonconforming restaurant and catering use and then change it to an office use.7
It is undisputed in the record that the security agency did not obtain, as required by the Zoning Regulations,8 a certificate of occupancy before commencing its use of the space for office purposes. Such use of the space by the security agency has therefore been, since its inception in 1968, an illegal use rather than a nonconforming use within the purview of D.C.Code 1973, § 5-419.9
*819Petitioners say that for many years prior to 1968 the space was used for office purposes by Hadassah, a women’s organization, and the suggestion is that a nonconforming office use resulted.10 But aside from the unsupported statement of petitioners’ Vice President, there is no showing in the record that any such office use was ever sanctioned by an occupancy permit as required by Zoning Regs. § 8104.1 or that it was otherwise a legal use.
The burden of proof rests upon the person asserting the right to the continuation of a non-conforming use that his use existed prior to and at the time of the enactment of the restrictive ordinance, that it was a lawful use, and that it was such a use as is entitled to the court’s protection. ... [82 Am.Jur.2d Zoning and Planning § 183 at 694 (1976); footnotes omitted.]
The Board is authorized by Zoning Regs. § 8207.2 “. . .to grant special exceptions . . . where in the judgment of the Board such special exceptions will be in harmony with the general purpose and intent of the zoning regulations”. Petitioners urge in this connection that the Board should have, by a liberal interpretation of the Zoning Regulations, carved out a special exception, so as to legalize a use which is now and has been since its inception an illegal use.11 The Board refused, concluding that a special exception, under the facts disclosed by this record, would not be in harmony with the general purpose and intent of the Zoning Regulations. We agree because Zoning Regs. § 7101.1 specifically provides that “. . . it is the purpose of this Article to provide for strict regulation of nonconforming uses.”
In our view the Board’s interpretation of the Zoning Regulations was not plainly erroneous or inconsistent with the purpose and intent of such regulations. We must therefore regard the Board’s interpretation as controlling. Dietrich v. BZA, D.C.App., 320 A.2d 282, 286 (1974); Rose Lees Hardy Home & School Ass’n v. BZA, D.C.App., 324 A.2d 701, 706 (1974). See also Taylor v. BZA, D.C.App., 308 A.2d 230, 232 (1973).
Petitioners contend next that the Board erroneously denied a variance to permit an office use in the R-5-C district. We note at the outset that a use variance may be granted only to alleviate undue hardship:
The variance procedure has many purposes. It is designed to provide relief from the strict letter of the regulations, protect zoning legislation from constitutional attack, alleviate an otherwise unjust invasion of property rights and prevent usable land • from remaining idle. These purposes infuse meaning into the phrase “exceptional and undue hardship”. The authorities widely recognize that the hardship envisioned by the statute must be great. . . . [Palmer v. BZA, D.C.App., 287 A.2d 535, 541-42 (1972); footnotes omitted.]
Thus to obtain a variance, it is fundamental that the property owner must prove that he qualifies for the requested relief. Taylor v. BZA, supra, 308 A.2d at 234. In this connection, we have held that:
[A] necessary element of proof of such hardship is evidence showing the inability of the applicant to make a reasonable disposition of the property for a permitted use. [Clerics of Saint Viator, Inc. v. BZA, D.C.App., 320 A.2d 291, 296 (1974).]
In short, it must be shown that strict application of the Zoning Regulations would preclude the use of the property for any purpose to which it may reasonably be adapted. *820Palmer v. BZA, supra, 287 A.2d at 542; A. L. W., Inc. v. BZA, D.C.App., 338 A.2d 428, 432 (1975). That is, indeed, a heavy eviden-tiary burden, and it is one that petitioners have not sustained.
Here, it is conceded that the bulk of any hardship falls not on petitioners as owners of the building, but on their tenant who will be forced to relocate its electronic equipment. But as we pointed out in Palmer v. BZA, supra, 287 A.2d at 542:
The tenant’s . . . problems . are immaterial. At issue are the difficulties of the owner. ... It cannot be said that the tenant’s financial distress has caused the owner any difficulties whatsoever.
See A. L. W., Inc. v. BZA, supra, 338 A.2d at 431.
The only hardship petitioners are able to point to that peculiarly affects their interest in the property is the cost of remodeling the unit for residential purposes, and the anticipated difficulty in renting it because of the close proximity to the restaurant-caterer. An examination of the record, however, reveals that there are other residential units near the restaurant-caterer, and that the vacancy rate among the residential apartments on the ground floor of the Chastleton is no greater than the vacancy rate on the upper floors of the building which are completely residential in character.
Petitioners urge that the space in question has been used as an office, albeit illegally, for at least twenty years. This fact, however, is of no consequence since any hardship which results from converting the unit from an illegal use back to a legal use was self-imposed. Dwyer v. BZA, D.C.App., 320 A.2d 306 (1974); Taylor v. BZA, supra, 308 A.2d at 235; Clouser v. David, 114 U.S.App.D.C. 12, 309 F.2d 233 (1962). Moreover,- it is well established that a mere desire to use property in a given manner, or in a manner designed to return a greater profit, does not constitute a showing of an undue hardship that will support the granting of a use variance. Taylor v. BZA, supra, 308 A.2d at 236; Palmer v. BZA, supra, 287 A.2d at 540. In short, we cannot say that the Board’s denial of the variance request was either arbitrary or capricious or unsupported by substantial evidence. The petitioners simply did not carry their burden of proof.
Petitioners contend also that a proper quorum was not present when their motion for reconsideration, reargument or rehearing was denied. Section 5.45 of the “Supplemental Rules of Practice and Procedure Before the Board” provides:
Any motion to reconsider an application or appeal . . . must be approved by at least four (4) affirmative votes.
The record reveals that petitioners’ motion was denied by a 3-0 vote. It is petitioners’ contention that § 5.45 requires the presence of 4 of the 5 members of the Board whenever such a motion is decided. The Board did not agree.
As we pointed out above, the Board’s interpretation of its own regulations is controlling unless that interpretation is plainly erroneous or is inconsistent with the purpose of the regulations themselves. Dietrich v. BZA, supra, 320 A.2d at 286; Salsbery v. BZA, D.C.App., 318 A.2d 894, 896 (1974); Taylor v. BZA, supra, 308 A.2d at 232.12
In our view the Board was within its province in rejecting petitioners’ contention regarding the applicable quorum requirements. See Dietrich v. BZA, supra, 320 A.2d at 282.
Accordingly, the decision of the Board is
Affirmed.
. Zoning Regs. § 3105.1.
. Zoning Regs. § 7104.
. Zoning Regs. § 7105.
. D.C.Code 1973, § 5^20(3).
. The building is located in an R-5-C district which is classified by Zoning Regs. § 3105.1 as general residential. While other uses are permitted in such districts if approved by the Board pursuant to Zoning Regs. § 8207, general office use is not permitted as of right or by special exception. See Zoning Regs. § 1302.1.
. The Board by an Order entered in its Appeal No. 9990 recognized the legal existence of such nonconforming uses.
. It does not escape attention that neither the lessee of the space occupied by the restaurant-caterer nor the security agency was a party to the proceedings. Nevertheless, we proceed to disposition of the issues since no question of standing is before us.
. Zoning Regs. § 1302.1 provides: that “[n]o building . . . shall hereafter be used . . except in conformity with these regulations.”
. Zoning Regs. § 8104.1 provides that unless a certificate of occupancy was issued or applied for before the effective date of the regulations “. . no person shall use any structure . . . or part thereof for any purpose other than a one-family dwelling until a certificate of occupancy has been issued to such person stating that such use complies with these regulations and the building code.”
. By D.C.Code 1973, § 5-419, it is provided that the lawful use of a structure as lawful and existing at the time of the adoption of any zoning regulation may be continued subject to conditions therein prescribed. The Zoning Commission is authorized in its discretion to regulate any extension or change of a nonconforming use.
. In Besthoff v. Zoning Board of Appeals, 34 A.D.2d 782, 783, 311 N.Y.S.2d 58, 59 (1970), it was said that “[a] non-conforming use may not be established through an existing use of land which was commenced or maintained in violation of a zoning ordinance; any such use is not an existing lawful use within the meaning of an ordinance which protects existing lawful uses”.
. Petitioners contend finally that the Sunshine Act, D.C.Code 1975 Supp., § l-1503(a), required that the Board’s deliberations on-petitioners’ motion for rehearing be in an open meeting. This contention has previously been rejected by this court in Dupont Circle Citizens Ass'n v. BZA, D.C.App., 364 A.2d 610 (1976), and Jordan v. District of Columbia, D.C.App., 362 A.2d 114 (1976).