I recently received my new house from the contractor. The contractor owned the land and he showed me his plans for developing the land. Based on these plans we signed a contract, including the plans as part of the contract. However, when I saw the completed house I noticed that it was ten meters smaller than the one I had been shown in the plans. Can I cancel the sale and tell him to keep the house and refund my money or am I obligated to take the house? Furthermore, if I do have to keep the house am I at least entitled to a partial refund or do we say that since there is no ono”o by immovable goods and since the difference in size is far less than one sixth (the house is two hundred square meters) there is no ono”o and I am stuck with the house as is, without even a partial refund of my money?
The first point to note is that this is a sale and not an employment agreement. The reason this is a sale is because everything – the land and materials – all originally belonged to the contractor. This is similar to the ruling of the Mahara Sasson (Responsa 119) in the case of a sofer who was commissioned to write a kesubo. He ruled that since all the materials belonged to the sofer, his agreement to write is classified as a sales agreement and not an employment agreement. Therefore your question if the rules of ono”o apply is very well taken.
However, based on a Gemoro we can rule out the rules of ono”o even though this is a sale. The Gemoro (Kiddushin 42B and Bava Basra 90A) writes that when the error is not in price but in measurements, even if the error is smaller than one sixth there is “return.”
Rashi explains that the reason for the difference is that it is very difficult to specify an exact price and therefore, we leave one sixth as a margin of error. However, it is possible to get measurements exact and therefore there is no rule of one sixth with regard to measurements. So according to this we can rule out the possibility that you have to take the house as is without receiving any kind of refund.
What remains to determine is whether you can demand all your money back or if you have to take the house. This depends on two disputes among the Rishonim. The first dispute is how to understand what the Gemoro means when it says there is “return”. Rashi (Kiddushin) and the Rashbam (Bava Basra) say it means that one can cancel the entire sale because it is considered a mekach to’us. Since one can be exact when it comes to measurements, if the seller is not exact, the sale is invalid. Therefore, according to this approach you can give the house back to the contractor and have all your money refunded.
The Ri Migash understands the word “return” differently from Rashi. He understands that it means that the difference between the incorrect amount and the correct amount must be given back. Thus, if the seller gave too little, the sale remains in force, but the seller must give what was lacking. Similarly, if he gave too much the customer must return the difference. The Ri Migash also explains the difference between a mistake in price and a mistake in amounts differently from Rashi. He explains that a mistake in price is a mistake in the actual sale. However, a mistake in the amount given takes place after the sale. Therefore, all that must be done is to adjust the amount which the customer received. The sale is not invalid since the sales agreement did not contain any errors.
There is a further dispute among the Rishonim in understanding the Ri Migash’s approach in case it is not possible to correct the error. The Ramban (Bava Basra 103B) sides with the Ri Migash in his dispute with Rashi. However, he writes that in case it is not possible to correct the amount, even the Ri Migash agrees that the sale is invalid. He specifically mentions a house that was built with improper measurements as an example of a sale that cannot be corrected. Thus according to the Ramban even the Ri Migash would agree that you can return the house to the contractor and have your entire payment returned.
However, the Rashbo (Bava Basra 103B) records the Ramban’s opinion and disagrees. He again specifically mentions a house built with improper measurements as an example, but disputes the Ramban, arguing that the general consensus of buyers is that if the seller does not and cannot provide the proper size the sale remains intact and only the price must be readjusted to suit the amount which was given. For example, if your house is ninety percent of the size it was supposed to be, then you are entitled to a refund of ten percent of the amount originally agreed.
The Rambam (Mechiro 15, 1) and the Shulchan Aruch (232, 1) who quotes the Rambam verbatim, clearly understood the Gemara like the Ri Migash. In their commentaries on the Rambam, the Magid Mishna understands their opinion as being like the Rashbo, but the Kessef Mishna and the Ran (Bava Basra 103B) understand the Rambam like the Ramban.
The Commentaries to the Shulchan Aruch also differ in their interpretation. Thus, the Sema (232,2) and the Nesivos (Chiddushim 232, 1) follow the Ramban but Rabbi Akiva Eiger (margin notes) comments on the Sema that the Rashbo disagrees and the Gra (232, 1) quotes both opinions.
Therefore, it would seem that if the contractor wants to return the difference in price and refuses to invalidate the entire sale, it will be difficult for you to force him to return your entire payment because we have a rule that one cannot force someone to give something, even if his position is only supported by a significant minority opinion.