The ruling on deducting a sum of money as compensation for a contractor's delay beyond the agreed deadline for completing construction

Question : Here we are dealing with a matter that contractors use in construction. For example, one might say to a contractor: "Build this house within six months. If the six months are up, you must deduct one hundred riyals, or one thousand riyals, or whatever amount they agree upon for each day of delay." Is this permissible or not?

Answer : We say that setting a time frame within which the construction can be completed is permissible. However, setting a time frame that is impossible is not permissible, because in the latter case the contractor would be taking a risk. It is well known that if the construction period is shortened, the price will be higher. In that case, the contractor will either gain or lose. But if the time frame is one in which the construction can be completed, there is nothing wrong with it. Yes.