Two questions are involved on this appeal: (1) Is the defendant liable on the policy sued on? (2) Did the court err in refitsing to make the Northwestern Furniture Company a party defendant ?
The policy contained the following provision: “Additions to or alterations in, or the construction of any building or structure, or elevator, are not covered under this policy.”
It is claimed by the appellant that the putting in of an extra set of doors in each of the entrances and the creation of a vestibule at each entrance is either an “addition” to or *630an “alteration” in the building, or else the “construction of a structure.”
It is conceded that the extra set of doors at each entrance was intended for winter use only, and that but one set would be maintained at each entrance during the summer months. The operation was somewhat more elaborate than the usual putting in place of storm doors and windows, but was of the same general nature. Wé think it is quite plain that the vestibule did not constitute an addition to the building. The word “addition” as there used should be held to mean enlargement or extension, so as to include additional space. Neither do we think that a temporary device put in place to keep out the wind and cold in the winter time should be held to constitute an alteration of the building itself within the meaning of the policy. There was no substantial change made in the structure, if indeed there was any change at all, and we think the word “alteration” should be held to mean a substantial change. Bigelow v. Worcester, 169 Mass. 390, 48 N. E. 1; Comm. v. Hayden, 211 Mass. 296, 97 N. E. 783. It is also apparent that the putting in place of these doors was not the “construction of a structure.” In its usual and ordinary sense the word “structure” is applied to a building of some size, an edifice. Webster’s Diet. The policy was prepared by the defendant, and where ambiguity occurs therein the words are to be read most favorably to the insured. Bakalars v. Continental C. Co. 141 Wis. 43, 46, 122 N. W. 721; French v. Fidelity & C. Co. 135 Wis. 259, 265, 115 N. W. 869; Summerfield v. Phœnix Assur. Co. 65 Fed. 292, 297; Gillet v. Bank of America, 160 N. Y. 549, 55 N. E. 292. It seems reasonably certain that what the defendant aimed to protect itself against was the danger incident to the construction work and the wrecking of buildings, and not to a trifling act such as is here involved.
The remaining question is: Did the court err in refusing to make the Northwestern Furniture Company á party de*631fendant ? The appellant insists that it has a right of subro-gation, and that, having such right, it is entitled to have the Furniture Company before the court to the end that it might be bound by any judgment rendered which adjudicated that the plaintiff was legally liable for the injuries sustained by Mrs. Easson.
Sec. 2610, Stats., makes it obligatory on the court to bring in additional parties when a complete determination of the controversy cannot be had without their presence, or where the subject matter of the controversy is such that persons not before the court have such an interest therein as requires them to be made parties for their due protection.
It is obvious that the case does not fall within the compulsory provisions of this section. The controversy between the parties to this suit can be fully and finally settled without the presence of the Furniture Company. It is not necessary that the latter company should be made a party for its protection, because it is not concluded by the result reached on any question litigated in the present action in which it is interested. We do not pass upon the question whether the court in the exercise of its discretion might not have made the order asked for. We simply hold that it is not an abuse of discretion to refuse to do so. Neither do we decide -whether or not the right of subrogation exists. The Furniture Company is interested in that question, and is entitled to be heard upon it at the proper time.
By the Court. — Judgment affirmed.
MARSHALL, J., dissents.