At issue is whether the owners of cooperative units located at 1010 Memorial Drive, in Cambridge, are required to comply with G. L. c. 148, § 26Al!i, by installing automatic sprinklers in each room of their residential units. The plaintiffs, owners of shares representing individual residential units, appeal from a determination by the Automatic Sprinkler Appeals Board (board) that G. L. c. 148, § 26AV2, applies to their units and from a declaration by the Superior *662Court judge to the same effect. We transferred the case to this court on our own motion. We reverse and remand to the Superior Court for a declaration that cooperatives are within the condominium exemption.2
The facts are not in dispute. The owner shareholders of individual units are organized as a corporation entitled 1010 Memorial Drive Tenants Corporation. The corporation owns the building located at 1010 Memorial Drive in Cambridge (building) and the unit shareholders are the only members of the corporation. The unit owner shareholders of the corporation are the residents of the building, who lease their units from the corporation on a long-term basis, consistent with a cooperative style of ownership.
General Laws c. 148, § 26A1/2, requires that all buildings over seventy feet in height and constructed or substantially altered after January 1, 1975 (see St. 1975, c. 676, § 3), be equipped with automatic sprinklers. In 1986, a subsequent statute was passed that applied the automatic sprinkler requirement to buildings built before January 1, 1975. G. L. c. 148, § 26AV2.3 That statute included a provision exempting buildings organized as condominiums, but was silent as to cooperatives. Similarly, G. L. c. 148, § 261, is designed to require automatic sprinkler systems in newly constructed or substantially rehabilitated condominiums, but is silent as to cooperative units.4
The unit owner shareholders maintain that cooperatives *663and condominiums are sufficiently similar that they should be considered the same for the purposes of the statute. We agree. The dwelling units (or share) in each are bought and sold. Each type of management requires authorization before making any major modification, the cooperative owner shareholders through the board of directors, and the condominium owners through the condominium association. Each unit is considered “owned” by the person named in the deed in the case of condominiums, or the person named as the owner of the share. Both cooperative owners and condominium owners have their percentage interest in the building organizing unit linked to the fair value of their unit in relation to the value of the building as a whole. Both pay their proportionate value of the building maintenance expenses. In every relevant sense, each type of ownership has similar benefits and obligations.
Where the Legislature enacts a comprehensive scheme of legislation, we have recognized that “there are likely to be casual overstatements and understatements, half-answers, and gaps in the statutory provisions. . . . [T]he courts are called on to interweave the statute with decisions answering the difficulties and composing ... an harmonious structure faithful to the basic designs and purposes of the Legislature.” Cummings v. Secretary of Envtl. Affairs, 402 Mass. 611, 628-629 n.12 (1988), quoting Mailhot v. Travelers Ins. Co., 375 Mass. 342, 345 (1978). We conclude that the omission of cooperatives throughout the statutes is a gap in the statutory provisions.
The dissent suggests that it is inappropriate for us to consider the statutory interpretation because neither the judge nor the board did so. We do not agree. It is fundamental that issues of statutory interpretation should be resolved prior to reaching any constitutional issue. “We do not decide constitutional questions unless they must necessarily be reached.” Commonwealth v. Paasche, 391 Mass. 18, 21 (1984). Massachusetts Council of Constr. Employers, Inc. v. Mayor of Boston, 384 Mass. 466, 470 (1981). In this case, the result follows a fundamental rule of statutory construction. We turn to the merits.
*664The primary reason offered as to why cooperatives are not included in the statute is that the Legislature made a distinction between individually owned units and individually rented units. According to the trial judge, “tenants in large residential buildings are subject to the will of landlords to maintain the safety of the property.” The reasoning follows that because each shareholder in a cooperative must lease his or her unit from the landlord corporation, rather than owning the unit outright, the owner shareholders of the shares are in the same position as a traditional rental tenant. That concern is absent here where the unit owners or shareholders are their own landlord.
A second distinction offered is that the sprinkler systems in high rise buildings help to eliminate the need for firefighters to risk their lives in the Armageddon of fighting a fire in the little boxes that serve as homes to the residents. However, the risk of a fire in a residential high rise building and the dangers of fighting that fire are no different in a cooperative than they are in a condominium. That risk is unrelated to the legal ownership structure of the building. “[W]e . . . look to ensure that the agency’s action has some express or implied basis in the governing statute.” Globe Newspaper Co. v. Beacon Hill Architectural Comm’n, 421 Mass. 570, 584 (1996).5
The dissent suggests that the court acts inappropriately today by not construing this statute literally. We do not agree. We construe a statute to fulfil “the intent of the Legislature ascertained from all its words construed by the ordinary , and approved usage of the language, considered in connection with the cause of its enactment, the mischief or imperfection to be remedied and the main object to be accomplished, to the end that the purpose of its framers may be effectuated.” Telesetsky v. Wight, 395 Mass. 868, 872 (1985), quoting Commonwealth v. Galvin, 388 Mass. 326, 328 (1983). None of the sections governing fire prevention requires any individual owner of an older residential building to include sprinklers in each room. See G. L. c. 148, §§ 26A, 26AV2, 26B, 26C, 26D, 26E. The Legislature has limited the impact of the statute to commercial and residential landlords who can pass the costs along to tenants.
*665As we read the statute, the Legislature has granted these exemption6 so as not to harm the buying and selling of personal residences as well as to ensure that homes are not lost because owners cannot afford to install the expensive equipment. Those reasons apply to cooperatives as well. An analysis of the statute convinces us that cooperatives are included within the language concerning condominiums.7 The failure to mention cooperatives represents a gap in the legislation. See Mailhot, supra at 345.
In sum, the board made no findings of fact as to any firefighting reasons why cooperatives should be treated differently from condominiums.8 The board did not consider the Legislature’s intent not to apply this statute to individual owners. The judge erred in not considering a statutory basis for his decision before considering whether there was a constitutional issue.
We remand the cases to the Superior Court for entry of a declaration that cooperatives are within the condominium exemption.
So ordered.
We address only the issue necessary to resolve the case and do not discuss the other issues raised by the plaintiff or the dissent.
General Laws c. 148, § 26A1/2, reads: “Every building or structure of more than seventy feet in height . . . and constructed prior to January first, [1975], shall be protected with an adequate system of automatic sprinklers in accordance with the provisions of the state building code; provided, however, that sprinklers shall not be required to be installed in . . . buildings where construction has commenced prior to January first, [1975] and which have been submitted to the provisions of [c. 183A].” Chapter 183 A of the General Laws is generally known as the condominium statute.
If the statute is interpreted as the defendants suggest, then older, taller cooperatives would be required to have a sprinkler system in every unit but shorter, newly constructed cooperatives would not be required to install sprinkler systems. Older, taller condominiums, on the other hand, would be exempt under G. L. c. 148, § 26A1h, but required to have sprinklers under G. L. c. 148, §§ 26A and 261, if they are newly constructed, irrespective of height. That result as to condominiums is in keeping with the legislative *663intent; the result as to cooperatives is not. “A statute . . . should not be construed in a way that produces absurd or unreasonable results when a sensible construction is readily available . . . .” Manning v. Boston Redevelopment Auth., 400 Mass. 444, 453 (1987).
A third explanation regarding the exclusion of cooperatives from the statute is that the Legislature has chosen to act on an incremental basis. This explanation fails when examining the statute, which excepts all individual owners of condominiums, one and two-family homes.
There are limited exceptions. Local governments are authorized to, at their option, require single or two-family homes to include smoke detectors. G. L. c. 148, § 26E. Also, smoke detectors are required to be installed on the sale of such homes. G. L. c. 148, § 26F.
The dissent argues in a footnote, post at 667 n.l, that the legislative history of the bill, which added condominiums to the excepted buildings through an amendment during the legislative process, indicates that the Legislature intended to include cooperatives under the auspices of the statute. The fact that the Legislature amended the bill only confirms further that it was concerned with individual owners, and also would support a theory that the failure to mention cooperatives is a “gap” in the statute.
The defendants claim, but there is no evidentiary support, that it is more difficult to enforce installation of sprinklers in condominiums than it is in cooperatives. The defendants need only interact with the board of directors in cooperative buildings or the condominium association in condominium buildings.