N ORTONI, J.

This is a suit by a landlord against his tenant for the value of a fire escape constructed by the landlord on the demised premises during the term of the lease. The finding and judgment were for de-„ fendant and plaintiff prosecutes the appeal.

Plaintiff is trustee under the will of Pierre Chouteau, Jr., and as such possesses the legal title to the demised premises. It appears that by an instrument of writing duly executed between the parties plaintiff leased and demised to defendant a certain four story brick building situate at the northwest corner of the levee and Yine street in the city of St. Louis, for a term of five years and eight months from the first day of June, 1906. The lease requires defendant, which is a business corporation, to occupy the premises for business purposes only and it appears they were so occupied by other tenants immediately before. There is no express agreement to be found in the lease which requires the tenant to construct a fire escape on the building un*486less such a covenant is contained in obscure language to be hereafter adverted to.

After defendant had occupied the premises under the lease for several months, the authorities notified both plaintiff, the OAvner, and defendant, the tenant, to construct a fire escape thereon in accordance Avith the statute requiring the same. Both plaintiff and defendant declined to do so, each insisting that the laAV fixed the duty upon the other. After some controversy about the matter, plaintiff and one of defendant’s officers Avere both informed against by the prosecuting attorney in the court of criminal correction as for a misdemeanor for their failure to construct the fire escape in accordance Avith the statute. In order to obviate further annoyance and prosecution about the matter, plaintiff induced the dismissal of the criminal proceedings by constructing the fire escape on the building, for Avhich he paid two hundred and twenty-seven dollars, and thereupon instituted this suit to recover from defendant the amount so expended as though he had paid out the amount mentioned for its use and benefit.

Our statute (Luavs of Missouri 1901, p. 219, as amended; see Laws of Missouri 1903, p. 251; see An. St. 1906, sec. 9053-1) declares:

“It shall be the duty of the owner, proprietor, lessee or keeper of every .... building .... which is used as a business place .... Avhich has a height of three or more stories to provide said structure Avith fire escapes attached to the exterior of said building, etc., etc.”

It thus appears that in so far as the general public is concerned, the law lays an obligation against both the owner and lessee to construct fire escapes. [Johnson v. Snow, 201 Mo. 450, 100 S. W. 5; Yall v. Snow, 201 Mo. 511, 100 S. W. 1; Contant v. Snow, 201 Mo. 527, 100 S. W. 5.] But as between the owner and the lessee, aside from any contract, the obligation of the law is not identical with that which obtains with refer*487ence to the public, for in such circumstances the duty of constructing the fire escape rests primarily upon the owner of the property. The question has been pointedly decided by the Supreme Court in Yall v. Snow, 201 Mo. 511, 524, 525, 100 S. W. 1. It is true, as a general proposition, that by the common law the burden of repairs on the demised premises rests upon the tenant, and, unless he covenants to do so, the landlord is not required to construct appurtenances nor repair the premises after having placed them in the possession of the lessee. [1 Taylor on Landlord and Tenant (9 Ed.), secs. 327, 328; Ward v. Fagin, 101 Mo. 669, 14 S. W. 738; Herdt v. Koenig, 137 Mo. App. 589, 594, 119 S. W. 56.]

But to this general rule there is a well established exception which obtains with respect to the construction of such permanent improvements or fixtures as fire escapes, where the duty is enjoined by a positive statute, as here. The doctrine which obtains as to this matter is thus stated by McAdam on Landlord and Tenant, vol. 1 (3 Ed.), 440:

“To the general rule that the landlord is under no obligation to repair except by force of an express covenant there is one exception. If a statute makes it the duty of a landlord to repair in any particular, such repairs must be made by him in the absence' of an agreement by the tenant to make them. Thus, where a city charter imposes upon the owner of tenement houses the duty of keeping fire escapes attached thereto in repair, it is the duty of the owner to keep the fire escapes in such repair that they will be suitable for the purpose designed. It is not within the range of ordinary repairs which a tenant, in the absence of an agreement to the contrary, is required to make.. [McAlpin v. Powell, 70 N. Y. 126; s. c., 26 Am. R. 555; Willy v. Mulledy, 78 N. Y. 310; 6 Abb. N. C. 97.] ” See, also, 2 Wood on Landlord and Tenant (2 Ed.), sec. 381, to the same effect. That the doctrine above stated is the law of this state is obvious from the remarks of the court and citation of *488authorities in Yall v. Snow, 201 Mo. 511, 521, 524, 525, 100 S. W. 1. It thus appears that as between the plaintiff owner and the defendant lessee the obligation to construct the fire escape primarily obtains against the owner of the property and no recovery may be had against the defendant on account thereof unless it covenanted to do so. The mere fact that defendant leased the premises for business purposes with knowledge that the fire escape which the law required had not been constructed will not imply a covenant to the effect that it should assume the burden suggested; for implied covenants in leases are such only as the law raises from the relation of the parties or from the use of certain terms in establishing that relation. [1 Taylor on Landlord and Tenant (9 Ed.), sec. 252; 1 McAdam on Landlord and Tenant (3 Ed.), pp. 362, 364, secs. 113. 114.]

But it is said that the lease contains an express covenant by ■which the duty to construct the fire escape is assumed by the defendant. The express covenant relied upon is as follows:

“The said premises shall be kept in good order and repair, and free from xany nuisance or filth upon or adjacent thereto, at the expense of said lessee and shall be used by said lessee, and by all persons occupying the same, in compliance with and subject to all laws or ordinances of the said city of St. Louis and State of Missouri.’ ’ Of course, there are no words contained in this covenant Avhich in express terms refer to the fire escape, but it is argued as the statute requires fire escapes to be constructed on buildings more than three stories in height occupied for business purposes, the lessee kneAV at the time of executing the lease that an occupation of the premises Avithout constructing fire escapes thereon would render it amenable to the penalty of the statutes in such cases made and provided. As to this matter, the same may be said of the plaintiff, for the statute levels its penalties against the owner of the building who omits to construct the fire escape as -well as against the *489lessee. Besides, the primary duty of construction rests upon the owner. However, a proper disposition of the case must turn upon the construction of the covenant quoted, for unless defendant assumed an obligation therein to construct the fire escape, then none obtains against it as between it and the owner. Express covenants in leases are those which are created by the written words of the jjarties declaratory of their intention, and it is true no precise or technical language is necessary for the purpose of creating a covenant. But in every case it is essential for the court to ascertain from the language used a clear intention of the parties to. agree about the particular subject-matter before an express covenant may be deduced and declared to exist. [1 Taylor on Landlord and Tenant (9 Ed.), see. 246; Smiley v. McLauthlin, 138 Mass. 363, 364, 365.] The rule of construction -which obtains with regard to express covenants in leases requires them to be interpreted according to the obvious intention of the parties as collected from the whole context of the instrument and in consonance with the reasonable sense" of the words employed. Furthermore, such express covenants are to be construed more strictly than those which are implied, for when parties have entered into an agreement with express stipulations touching a particular subject-matter, it is presumed that they have expressed all of the conditions by which they intend to be bound, and the courts will not extend their covenants by interpretation unless the implication is clear and undoubted. [1 Taylor on Landlord and Tenant (9 Ed.), sec. 256: 1 McAdam on Landlord and Tenant (3 Ed.), p. 364; Smiley v. McLauthlin, 138 Mass. 363, 364, 365.]

When we give attention to all of the relevant provisions of the lease to the end of ascertaining the intention of the parties with respect to the matter now in judgment, it is clear that plaintiff’s theory is not aided by the mere fact defendant leased the premises for business purposes, for by the very terms of the lease plain*490tiff required a covenant from it to so occupy them. The covenant is that the premises shall not be used or occupied for any purpose other than that of general business purposes without the written consent of the lessor. From this it is obvious that the use of the premises by defendant no more occasioned the necessity for a fire escape than did. the act of plaintiff which required a covenant that they should be so used. However, this thought is really beside the question of construing the covenant above quoted but it is advanced in the briefs as proper matter for consideration in interpreting the intention of defendant, for it is said it devoted the premises to a use which brought them within the pale of -the statute requiring the construction of a fire escape. When the covenant relied upon is carefully scrutinized, we believe there are no words therein contained which signify an intention on the part of defendant to assume the burden of constructing a fire escape on the building. The substance of the agreement contained in the covenant is that the lessee will keep the premises free from any nuisance or filth at its expense and use the same in compliance with and subject to all laws or ordinances of the city of St. Louis and State of Missouri. As suggested in the brief, this covenant is as to the manner in which the premises shall be kept and used. It is therefore a restrictive covenant. Instead of affording evidence of an intention to do anything, it implies an intention not to do. Defendant agrees not to devote the premises to a use other than that which complies with the laws of the state and the ordinances of the city. Upon recalling that express covenants in leases are to be construed in the light of the presumption that parties entering into an express agreement about a particular subject-matter will employ language signifying a clear and undoubted intention with respect to the same, it is obvious that we are unable to interpret the covenant referred to as one requiring defendant to construct a fire escape. No word suggestive of a fire *491escape is contained in tlie covenant and had the parties contemplated this important permanent structure, the duty to construct it could have been affixed against defendant by the insertion of but two or three words.

The judgment should be affirmed. It is so ordered.

All concur.