Purity: Purification of Walls and Earth by the Sun

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 188

If the sun shines on one side of an impure wall and as a result the other side of the wall – on which the sun did not shine – also becomes dry, both sides become pure. However, if one day the sun dries the exterior of a wall or some earth and another day its interior, then only its exterior becomes pure.

-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)