Tbe demurrer admits tbe material facts alleged in tbe complaint. Hence, it becomes necessary for us to determine whether or not tbe construction of tbe building as described in tbe complaint, pursuant to a parol agreement created reciprocal or cross easements as to each owner, in tbe hallways of tbe building. If so, are tbe defendants, tbe present owners of tbe Foster property, bound by said easements %

In tbe case of Reid v. King, 158 N. C., 85, 73 S. E., 168, tbe plaintiff bad constructed a party wall pursuant to a parol agreement with one Thompson, tbe owner of an adjoining lot. It was agreed that Thompson should have tbe right to use tbe party wall if and when be should construct a building adjacent thereto, at which time be should reimburse Reid for one-half tbe cost of tbe wall. It was further agreed that if Thompson should sell tbe lot without constructing a building thereon, be would inform bis grantee of tbe party wall agreement. Thompson sold bis lot to one King and informed him of tbe terms of bis agreement with plaintiff. King erected a building on tbe lot and used tbe party wall, but refused to reimburse Reid for one-half of tbe cost thereof. An action was instituted for tbe recovery of one-half of tbe cost of tbe wall, and tbe Court held tbe defendant obligated to pay bis pro rata part of tbe cost — not by reason of tbe agreement, but from tbe nature of tbe relation, or quasi ex contractu; and tbe Court said: “Tbe effect of such an agreement is to create cross easements as to each owner, which binds all persons succeeding to the estates to which tbe easements are appurtenant, and a purchaser of tbe estate of tbe owner so contracting would take it burdened with tbe liability to pay one-half tbe cost of tbe wall, whenever be availed himself of its benefits. 88 Mo., supra (p. 498). Tbe language of courts and of judges has been very uniform and very decided upon this subject, and all agree that whoever purchases lands upon which tbe owner has imposed an easement of any bind, or created a charge which could be enforced in equity against him, takes tbe title subject to all easements, equities, and charges, however created, of which be has notice. 88 Mo., supra. Lord Cottenham said, in Tulk v. Moxhay, 2 Phil. (Eng. Ch.), 774: ‘If an equity is attached to property by tbe owner, no one purchasing with notice of that equity can stand in a different situation from tbe party from whom be purchased.’ But although tbe covenant, when regarded as a contract, is .binding only *484between the original parties, yet in order to give effect to their intention it may be construed by equity as creating an incorporeal hereditament (in the form of an easement) out of the unconveyed estate, and rendering it appurtenant to the estate conveyed; and when this is the case, subsequent assignees will have the rights and be subject to the obligations which the title or liability to such easements creates. A purchaser of land, with notice of a right or interest in it existing only by agreement with his vendor, is bound to do that which his grantor had agreed to perform, because it would be unconscientious and inequitable for him to violate or disregard the valid agreements of the vendor in regard to the estate of which he had notice when he became the purchaser. 88 Mo., supra; Spencer’s case, 1 Smith L. C. (6 Ed.), p. 167. See also Spaulding v. Grundy, 126 Ky., 510, and cases cited; Richardson v. Tobey, 121 Mass., 457; 30 Cyc., 788 and 795. . . . The statute of frauds does not apply. The equity arises regardless of any promise except, perhaps, that which is fairly implied by law. 20 Cyc., 282; Pitt v. Moore, 99 N. C., 85; Ray v. Honeycutt, 119 N. C., 510; Tucker v. Markland, 101 N. C., 422.”

In the instant case, the original parties agreed, for all practical purposes, to substitute common hallways on both floors of the building in lieu of a party wall and constructed the building accordingly. For approximately seventeen years the entrances, stairway and hallways were used as contemplated by the original builders and so used for six years by these defendants.

The greater weight of the authorities seem to hold that no easement or quasi-easement will be created by implication, unless the easement be one of strict necessity, but we think that means only that the easement should be reasonably necessary to the just enjoyment of the properties affected thereby, and it is so stated in Thompson on Real Property, Vol. 1, sec. 409 (369), p. 668, citing many cases, among them Bowling v. Burton, 101 N. C., 176, 7 S. E., 701. This is in accord with the decision of this Court in the case of Ferrell v. Trust Co., 221 N. C., 432, 20 S. E. (2d), 329, in which we held: “It is-a general rule of law that where one conveys a part of his estate, he impliedly grants all those apparent or visible easements upon the part retained which were at the time used by the grantor for the benefit of the part conveyed, and which are reasonably necessary for the use of that part,” citing numerous authorities.

The fact that the title to the Foster property, now owned by the defendants, and the title to the property of the plaintiff, were not vested in a common owner at the time of the construction of the building involved herein, is immaterial. Easements created by implication or *485estoppel do not necessarily stem from a common ownership. But where adjoining properties of separate owners have been developed in relation to each other, so as to create cross easements in the stairways, hallways, or other private ways, serving both properties, such easements, if open, apparent and visible, pass as an appurtenant to the respective properties, and are binding on grantees, although not referred to in the conveyance. This view is in accord with many authorities from other jurisdictions.

In 19 C. J., sec. 137, p. 934, it is said: “If a building consisting of several apartments is so constructed that all the occupants must enter and depart by the same hall and stairway these become a way of necessity upon the sale or lease of part of the building.” Also sec. 145, p. 939, where it is stated: “One who purchases land with notice, actual or constructive, that it is burdened with an existing easement takes the estate subject to the easement, and will be restrained from doing any acts which will interfere with the benefit and enjoyment of the easement to the full extent to which the party having a right thereto, who has not parted with or impaired the same, was entitled at the time when such purchaser bought. He has no greater right than his grantor to prevent or obstruct the use of the easement. The rule applies whether the sale is voluntary or involuntary. Frequent applications of the rule are found in the case of private rights of way, stairways, and water rights.” Welfare B. & L. Asso. v. Kreiger, 226 Vis., 105, 275 N. V., 891.

In the Appeal of Glelland, et al., 133 Pa., 189, 19 A., 352, the facts and holding of the Court are succinctly stated in the syllabus, as follows : “The owners of adjoining lots built a single building covering both lots. The only access to the upper stories was by stairs which were altogether on one lot. Held, that the erection of such building constituted an executed license, in the nature of an easement, on the part of the owner of said lot, allowing the owner of the other lot to use such stairs.”. It is stated in the opinion of the Court that “The building being cast by common consent in its present permanent form, neither party can revoke the arrangement, upon the faith of which the money of the other has been expended. Each and every part is affected with what, in its nature, is a permanent servitude, so long as the building itself stands. It cannot be changed from its present form, nor the right of common access now provided for, be interfered with, at the will of either party, but only by the common consent of all.” A similar conclusion is reached by the Court in the case of Binder v. Weinberg, 94 Miss., 817, 48 Southern, 1013. The factual situation was similar to the instant case, and while the Court held the evidence insufficient to create an “easement of strict necessity,” it did hold: “That the appellee is estopped, by equitable considerations, from obstructing this common hallway with this new *486room. It is plain that the original verbal agreement between the parties who built the party wall, and the common hallway above and on the party wall, expressly stipulated that each of the parties was to have the use of the entire hallway, that the light and ventilation of that hallway were not to be interfered with by either, and that the plan of the two buildings, as related to the party wall, and also the common hallway, the way in which both were constructed, and the use to which the common hallway was to be put by both, involved a unity of design; that design being that each party should have full use of the whole common hallway, and derive the full benefit of unobstructed light and air and passageway therein. This is clear from the evidence. The evidence of the appellee himself plainly shows that he had occupied an office in this building for five years as a tenant, from its original construction, and that prior to his purchase he was thoroughly conversant with the plans of this building, and that he knew, when he purchased the building, that the wall was a party wall, that the stairway leading up to the hallway was a party stairway, that the stairway in the rear was also a party stairway, and that the hallway, at the time he purchased it, was and had been used all the while and owned as a party hallway, ever since the building was erected. ... It is further evident, from the verbal agreement, that the appellant had put his money into the construction of this common hallway, as well as of the party wall, upon the faith of that verbal agreement that he should have the use of the whole of the common hall, just as his cobuilder should have the use of the whole common hallway, and that it was the purpose of this verbal agreement that this common hallway should be left entirely unobstructed to be used, according to the agreement, only as a common hallway. It was the plain purpose and plan, as shown by the construction and building of the party wall and common hallway, that the common hallway should be so used by both in its full extent, and should not be obstructed in any part of it.”

It is also stated in 26 C. J. S., sec. 43, p. 707: “If a building is so constructed that all the occupants must enter and depart by the same hall and stairway, an easement for the use of the hall or stairway is impliedly granted on the sale or lease of part of the building.” To the same effect is the holding in the case of Forde v. Libby, 22 Wyo., 464, 143 Pac., 1190, where it is stated: “Where owners of adjoining lots orally agreed upon a private way between their lots and constructed their improvements with relation thereto, each was estopped from disputing, the other’s right to such way, and that estoppel extended to their grantees, *487wbo took witb notice of tbe way, although it was not expressly reserved.” Wright v. Barlow, 169 Okla., 472, 37 Pac. (2d), 958.

We think the demurrer was properly overruled.

Affirmed.