Is it permissible to plaster a mosque with impure clay?
Chapter on Praying with Impurity and Other Matters
Al-Mughni
Book of Prayer
Primary text
It is disliked (*makruh*) to plaster a mosque with impure clay, to pave it with impure bricks, or to construct it with impure mud bricks (*labin*) or impure kiln-fired bricks (*ajur*). If a worshipper prays while his body or clothes touch the impure ground, his prayer is invalid.