As has already been pointed out (ante, Sec. 102), in the case of improvements made by the purchaser or lessee of land at his own instance and for his own benefit, the seller or lessor is liable, if at all, only to the extent of the enhancement of the value of the land,1 while in the case of improvements made by the lessee in pursuance of the requirements of his lease the lessor may be held for the value of the labor and materials expended in making the improvements, whether or not the land is enhanced in value.2 The reason for the difference is plain. In the former case it cannot fairly be assumed that the owner of the land desired the improvements or that they are beneficial to him except as they have increased the market value of his property. In the latter, since he has required the lessee to expend the labor and materials, he cannot justly deny that he is benefited to the extent of their reasonable value.
Where the enhancement in the value of the land constitutes the measure of recovery it should be estimated as of the time of the surrender of the premises,3 and the cost of making the improvements is legitimate evidence as to the extent of the enhancement.4
In every case, whether it is the value of the improvements or merely the enhancement in the value of the land that may be recovered, the value of the benefit derived by the plaintiff from the use and occupation of the premises must of course be deducted.1 It is sometimes said that the plaintiff's profits must be deducted,2 but since the occupation is with the consent of the owner the reasonable value of the land would seem to be the true criterion.
1 Ford v. Stroud, 1909, 150 N. C. 362; 64 S. E. 1; Matthews v. Davis, 1845, 6 Hump. (25 Tenn.) 324; Rhea v. Allison, 1859, 3 Head (40 Tenn.) 176; Masson v. Swan, 1871, 6 Heisk. (53 Tenn.) 450. And see Glass v. Hampton, 1909, 122 S. W. 803, (Ky.).
2 Pulbrook v. Lawes, 1876, 1 Q. B. D. 284; Smith v. Smith, 1860, 28 N. J. L. 208; 78 Am. Dec. 49. And see cases cited ante, Sec. 102.
3 Treece v. Treece, 1880, 5 Lea (73 Tenn.) 220. See Masson v. Swan, 1871, 6 Heisk. (53 Tenn.) 450.
4 Masson v. Swan, 1871, 6 Heisk. (53 Tenn.), 450.