I respectfully dissent. I believe Gage Bowl had a duty to inspect the sign and the judgment of nonsuit should be reversed.
The majority correctly cites the following rule as stated in Schwartz: “An invitor may be liable for an injury, whether it occurs on his property or on a common passageway or on an adjacent sidewalk or street being used for his special benefit, if, and only if, the injury is caused by a dangerous condition, or unreasonable risk of harm, within the invitor’s control.” (Italics added.) (Schwartz v. Helms Bakery Limited (1967) 67 Cal.2d 232, 243, fn. 10 [60 Cal.Rptr. 510, 430 P.2d 68].) However, I respectfully disagree with the majority’s application of this rule to the facts of this case.
The majority contends Hamilton’s opening statement failed to indicate Gage Bowl exercised control over the sign within the meaning of Schwartz-It therefore concluded Gage Bowl had no duty to discover the dangerous condition of the sign. To the contrary, I believe Hamilton’s opening statement set forth facts to indicate Gage Bowl exercised sufficient control over the sign to impose upon it the duty to inspect the sign.
Hamilton clearly says in her opening statement the sign protruded one or two inches out from the wall. In general, “[n]o person may erect buildings or other structures on his own land so that any part thereof, however small, extends beyond his boundaries and encroaches upon adjoining premises. The maintenance of an encroachment may be a continuing trespass or a nuisance or both.” (2 CJ.S. Adjoining Landowners (1972) § 40, p. 43.) “[A]n encroachment may consist of ... an invasion of the space above [adjoining] land by projecting box screens, cornices and sills, eaves or gutters, or windows, or an overhanging roof or overhanging walls.” (2 CJ.S. Adjoining Landowners, supra, § 41, p. 44.)
Where a building overlaps or encroaches upon the space above adjoining land, the encroachment constitutes a nuisance, which may give a right of action for damages or for a mandatory injunction to compel removal. (4 Witkin, Summary of Cal. Law (9th ed. 1987) Real Property, § 426, p. 608; see also Kafka v. Bozio (1923) 191 Cal. 746 [218 P. 753, 29 A.L.R. 833]; Case v. Sisich (1929) 97 Cal.App. 106 [275 P. 492]; Harland v. Noto (1951) 105 Cal.App.2d 740 [233 P.2d 575].)
*1716In Kafka the upper portions of defendant’s building encroached a scant two inches over the space on plaintiff’s adjoining land. This invasion damaged an existing building on that lot. As the encroachment progressively increased and defendant did nothing, plaintiff brought suit. The Supreme Court held an encroachment upon the space above the land was a nuisance, and the maintenance of such an encroachment constituted a continuing trespass or a nuisance. (Kafka v. Bozio, supra, 191 Cal. 746, 747, 748, 751.) In Case, the First District held defendant’s bay windows, cornices, finish and extensions which were situated nine feet above ground and overhung eighteen inches into the space above plaintiff’s land constituted a nuisance. (Case v. Sisich, supra, 97 Cal.App. at p. 110.)
Not only have the courts found that minor encroachments over a landowner’s property constitute a nuisance, but they have made it clear the landowner has the right to have the offending nuisance removed. “[Tjhere can be no question but that a mandatory injunction may be granted to compel an encroachment to be removed from land with which it interferes.” (Lusk v. Krejci (1960) 187 Cal.App.2d 553, 556 [9 Cal.Rptr. 703]; also see Agmar v. Soloman (1927) 87 Cal.App. 127, 138 [261 P. 1029].) In Harland, the Second District upheld a mandatory injunction granted to remove eaves and a bay window which overhung adjoining property. (Harland v. Noto, supra, 105 Cal.App.2d 740.)
In light of the foregoing authority, Gage Bowl exercised control over the sign because, by virtue of the sign’s encroachment upon the airspace above Gage Bowl’s parking lot, Gage Bowl could have brought suit to compel the sign’s owner to remove the sign.1 Thus, although Gage Bowl did not own, hang or maintain the sign, it exercised the requisite control over that sign. This business owner was in a position to compel removal of the sign or, through threat of a nuisance suit, to force the sign’s owners to properly hang and maintain it. As the sign in fact was hung and maintained it constituted a “dangerous condition or unreasonable risk of harm” and one “within the invitor’s [defendant’s] control.” Hence, under Schwartz, Gage Bowl may be liable for the injury this dangerous condition caused to an invitee on its property.
“Where the dangerous condition is brought about by natural wear and tear, or third persons, or acts of God or by other causes which are not due to the *1717negligence of the owner, or his employees, then to impose liability the owner must have either actual or constructive knowledge of the dangerous condition or have been able by the exercise of ordinary care to discover the condition, which if known to him, he should realize as involving an unreasonable risk to invitees on his premises. His negligence in such cases is founded upon his failure to exercise ordinary care in remedying the defect after he has discovered it or as a man of ordinary prudence should have discovered it.” (Hatfield v. Levy Brothers (1941) 18 Cal.2d 798, 806 [117 P.2d 841], italics added.)
Hamilton does not claim Gage Bowl had actual or constructive knowledge of the dangerous condition of the sign. However, it is well established that the landowner’s lack of knowledge of the dangerous condition is not a defense. (Swanberg v. O’Mectin (1984) 157 Cal.App.3d 325, 329 [203 Cal.Rptr. 701].) ‘“[The landowner] has an affirmative duty to exercise ordinary care to keep the premises in a reasonably safe condition, and therefore must inspect them or take other proper means to ascertain their condition. And if, by the exercise of reasonable care, he would have discovered the dangerous condition, he is liable.’ ” (Ibid, at p. 330, italics in original.) The issue then is whether Hamilton’s opening statement set forth facts suggesting Gage Bowl had the opportunity to inspect the sign and whether a reasonable inspection would have revealed the unsafe condition.
“Whether the peril had existed for a time of sufficient duration to enable a reasonably prudent person to discover and remove it prior to appellant’s visit [is] a question of fact for the jury,” and may be proved by circumstantial evidence. (Lehman v. Richfield Oil Corp. (1953) 121 Cal.App.2d 261, 264 [263 P.2d 13]; see also Louie v. Hagstrom’s Food Stores (1947) 81 Cal.App.2d 601, 607 [184 P.2d 708].)
Hamilton claims in her opening statement the sign had been improperly and dangerously mounted “for years.” She claims Gage Bowl would have discovered the dangerous condition by simply climbing a ladder and looking at the way in which the sign was suspended, since it was hung with nails driven into the grout and Gage Bowl knew this to be unsafe.
Viewing the evidence proffered in the opening statement most favorably to Hamilton and drawing reasonable inferences therefrom, it cannot be said Gage Bowl did not have the opportunity to inspect the sign, nor that a reasonable inspection would not have revealed the dangerous condition. As established earlier, Gage Bowl had the power to compel removal or rehanging of the dangerous sign if it had conducted this inspection. Since Gage Bowl had control over the sign and knew, if defective, the sign could pose a *1718danger to its invitees, Gage Bowl had a duty to inspect and discover the dangerous condition of the sign.
Sound policy justifies imposing a duty on a business proprietor to inspect a sign which is attached to adjoining premises but which overhangs its business premises. There is always some risk a sign may fall onto land over which it hangs and injure any person below (particularly when the encroaching sign is as large as the one in the present case—approximately 10 feet by 6 feet). It is equally clear the owner of the premises upon which the sign encroaches has the power to remove the danger. The well-established rule is “that one who invites another to do business with him must exercise due care for his safety upon all premises of the business over which he exercises control.” (Schwartz v. Helms Bakery Limited, supra, 67 Cal.2d 232, 238.) It follows then that a business proprietor who invites customers onto its property for its own economic benefit should be duty-bound to ensure any overhanging signs pose no potential danger to those customers.
Assuming Hamilton could prove what she asserted in her opening statement, the sign was positioned in a way which gave Gage Bowl the legal right to demand its removal or repair. According to well-established principles of California law, this made Gage Bowl responsible for the safety of the sign and meant it owed Hamilton a duty to inspect that sign. Again according to the Hamilton’s opening statement, Gage Bowl made no such inspection during the many years the sign hung precariously over its parking lot. For these reasons, I would reverse the judgment for nonsuit.
Appellant’s petition for review by the Supreme Court was denied August 20, 1992. Mosk, J., was of the opinion that the petition should be granted.
Similarly, in Austin v. Riverside Portland Cement Co. (1955) 44 Cal.2d 225, 232 [282 P.2d 69] where plaintiff was electrocuted on defendant’s property when plaintiff’s crane touched a power line owned and maintained by the state, the court held while “[i]t is true that California rather than defendant was maintaining the power line, yet defendant had control to the extent that it could have the line deenergized ....’’