Yored L'sedei Chaveiro Property #13
Q: If the owner subsequently indicated interest in the enhancement, how much must he pay? Does it matter whether the property was fit for such an enhancement?
A: If someone enhanced another’s property, and the owner subsequently indicated positive interest in the enhancement — e.g., he built a fence around trees that were planted or completed a structure that was built — the enhancer “has the upper hand” (C.M. 375:3).
Rashi explains this to mean that if the capital gain is greater than the expenses, the owner pays the going rate of a contractor; if the expenses are greater than the gain, the owner must still pay the expenses, since his actions indicate retroactively that he was interested in such an expenditure (Sma 375:7; Pischei Choshen, Geneivah 8:17-18[37]).
Rosh limits this halachah to a property fit for such enhancement, but most authorities apply it even to a property not fit for such enhancement, since here the owner indicated his positive interest in the enhancement (ibid.).
