What is the ruling on someone participating in the renovation of two houses owned by another person, on the condition that they will be rented out and the funding partner will receive one-third of the rent for three years, after which they will recover their capital?

This transaction is religiously forbidden because it is a loan that draws benefit, which is a type of forbidden usury (riba). Lending to a friend on the condition of returning the amount with an added portion of the rental income is usury. Scholars have unanimously agreed that any increase or benefit stipulated by the lender for himself in a loan is usury, due to the prohibition in Islamic law of every loan that draws benefit, and because a loan is based on benevolence, not on realizing a benefit for the lender.