Is Tayammum valid?

Q: A person was mistakenly locked in his room and left alone in the house. The time for Salaat came and he had no water. He called out in vain for someone to come to his aid. The time of Salaat was elapsing. In this case was it permissible for him to make Tayammum and read his Salaah or not? If it was permissible, then will there be any Qadhaa of the Salaah read with Tayammum after being unlocked and water becoming available to him?

 

A: It is permissible to read Salaah with Tayammum in this case. After water becomes available the Salaat should be repeated.