Q 5, 6:
Is it permissible for me to demolish small Masjids (mosques) that contain shrines of sheikhs,
who are called Awliya’ (pious people)? Also, is it permissible for me to take parts of their debris, such as the roof or the cover so that I can benefit from them?
Building Masjids on graves is Haram (prohibited), as it is authentically established that the Prophet (peace be upon him) prohibited this and cursed those who do so. If they are built on them, the Muslim rulers should demolish them by way of elimination of evil, for they were not founded on piety and righteousness. (Part No. 1; Page No. 396) Likewise, if a group of Muslims have the authority and the ability, they themselves should tear it down, provided that this will not cause any Fitnah (turmoil) which cannot be overcome. At the beginning of his call to Tawhid (monotheism), the Prophet (peace be upon him) did not destroy the idols which were over and inside
the Ka`bah from the start. However, when the Muslims became powerful, he demolished them on the year of the Conquest of Makkah.
If they are demolished, it is permissible for you to take parts of the debris that you can make use of, as long as there is no fear of trouble or harm.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.