I live on the ground floor of a two story building and have been suffering from water leakage. The building is very old and when it rains, the rainwater seeps into the wall and eventually makes its way onto my ceiling and into my walls. I have had numerous discussions with my upstairs neighbor. He claims that it isn’t his issue because the problem existed before his purchase of the apartment and therefore the issue is between me and the previous owner of his apartment. To get estimates I brought three companies which deal with water leakage and they all agreed that it was a major job and would cost in the vicinity of fifteen thousand dollars. My neighbor, who any case wasn’t really interested in doing anything, brought a builder (not a person who specializes in fixing leaking walls) who gave a price of about three thousand dollars. The vast difference in price stemmed from the type of job the builder was planning on doing. Whereas the water leakage companies planned to do a basic job involving reconstruction of problematic areas, the builder only planned to apply sealant –which my companies claimed is only a temporary solution. Furthermore, whereas the water leakage companies guarantee their work, the builder does not, lending credence to the claim of my companies. Finally, with the rainy season fast approaching and my neighbor’s lack of co-operation, I myself brought a company to fix the problem. At that point, my neighbor said he would refuse access to his apartment unless I signed an agreement that no matter what I pay, he would only need to pay fifteen hundred dollars, half of the cost that the builder would have charged. Having no choice I signed the agreement. Is our agreement binding?
Before we can answer your question, we have to determine what you were entitled to if you had not signed an agreement. There are four questions.
The first is whether you could have forced your neighbor to participate in the cost of fixing the problem or could he have argued successfully that he doesn’t have a problem, and if you do, you should fix the problem yourself and pay for it yourself. The second issue is that even if he did have to participate, what percentage of the cost is his? Third, even if you could force him to participate in the cost of rectifying the problem and if we accept as a given that his solution was only temporary, do you have a right to force him to rectify the problem on a long term basis? Finally, is he correct that you should deal with the one who sold him the apartment?
The answer to the first question is that there are two reasons you could force him to participate in the cost of fixing the problem. One reason is that he is a joint owner of the outside walls. If the problem is not fixed, the jointly-owned property will be damaged and each of you will suffer a loss. The Ramo (178, 3) writes explicitly that when two people are partners in a building, and if the building is not repaired the building will suffer damage, each partner can force the other to participate in the cost of preventing the joint loss. Even when two people are not partners in a property but they each as individuals will suffer a loss from a single cause, they can each force the other to participate in the cost of preventing that loss.
The Nesivos (178, 3) says that this is the underlying principle for many halachos. For instance, the residents of a city can force each other to pay for many communal needs. The principle is that since each individual needs these services they can force each other to participate in the cost. Therefore, you could certainly force your upstairs neighbor to participate with you in the cost of repairing the wall.
As for the amount your neighbor has to pay for the repair, the rule is that if you each have the same amount of outside wall then you each have to pay half of the cost. This would seem obvious and can be derived again from the way costs for communal needs are divided between the members of the community (siman163, seif 3).
The issue of whether one neighbor can force the other to invest in the higher cost of a longer-lasting solution can be derived from the Gemoro (Bava Basra 2A) that discusses the rules governing the construction of a wall that prevents one from looking into his neighbor’s property, as required by the halachah. The rule is that if one wishes to build with better materials and the other with cheaper materials, custom prevails. Therefore, if the custom is to repair leaking walls by reconstructing the damaged areas and not just by applying sealant then you had the right to force your neighbor to pay half of the cost that you paid to the company that repaired your jointly-owned outside wall.
Finally, his argument that you should deal with the one who sold him the apartment is not valid since he is the current owner and the requirement to rectify the problem falls on the current owner. He may be correct that the seller is liable, but that is between him and his seller and has nothing to do with you.
It is important to note that even if you could not have initially forced your neighbor to pay more than half of what the builder would have charged, if you went ahead and did work that lasts longer than what the builder would have done, your neighbor would have to pay somewhat more than half of the cost that his builder asked for. The reason is that he is benefiting from the fact that your job lasts longer, and he will save money in the long run as a result of what you did. Thus the situation is ze nehene veze chosair, and if one benefits from another’s expenditure he must pay the value of the benefit he receives. This may or may not be half of the extra cost of the work you did, but in any case the agreement you signed meant that you would forego some money that was rightfully owed to you.
Thus we have established that you were coerced into signing an agreement to forego payment of money that you were entitled to receive under Torah law. We will now turn to the issue of whether such an agreement is binding.
The Gemara (Bava Basra 48A) says that if one sells under duress, the sale is valid. However, Tosafos (c.v. omar) clarifies that only a coerced sale is valid, but, a present that is coerced is not valid. Furthermore, critical for your question, is that the Shulchan Aruch (CM 205, 4) rules that a sale for less than the full value is classified as a present. He also rules that it is not necessary for the one who was coerced, to say anything at the time of the sale. As long as it is clear to beis din that the sale was forced, the sale is invalid. In your case, since your neighbor admits threatening that he would deny your workers access to his apartment if you refused to sign, he admitted forcing you to sign.
Since, as we derived earlier, under the terms of the agreement you signed you would receive less than what you deserve, therefore, your agreement is an agreement to give a present which is invalid if it was coerced. We should add that in your situation, even if we were to regard this as a sales agreement it would not be binding since a coerced sale is only valid after the seller receives payment, which did not happen in your case.
We should also note that the upstairs neighbor would not have been acting properly had he denied your worker’s access, since the only way the job could be done was by entering his property. Certainly, since we clarified that he was a partner, he was required to allow access to your workers in order to allow them to fix a problem for which he is partly responsible.
Even if he was not a partner but you needed access in order to fix your problem he is not allowed to prevent your workers’ access to his apartment. This can be derived from a ruling of the Ramo (siman 274) that if a person’s bees flew onto a neighbor’s tree the bee owner is allowed to cut down a branch of the tree in order to recapture his bees. Finally, we should note (CM 205, 7) that even a threat to cause monetary damage is considered coercion. Therefore, since your neighbor’s refusal to enable your workers to repair the damage would have caused you to suffer rain damage it is classified as a coerced agreement to give a present and the agreement is not valid, and beis din must determine how much he has to pay.