Building a Masjid under the house

Q: I built a house and I resolved, before constructing it, to build a Masjid (mosque) under the house. The construction works were done, the Qiblah (Ka`bah-direction faced in Prayer) was defined and the toilets of the Masjid were also built, in addition to the carpentry and nothing was left except for the paint work. The Masjid adopted its Islamic shape, but I heard from some people that it is impermissible to build a Masjid under a house, and therefore I stopped all the construction activities and closed the Masjid five years ago until I can discern the truth in this regard. What is Your Eminence's opinion regarding building a Masjid under the house? Bearing in mind that there are other small Masjids that were built beside it during that period, and they are now many? Kindly give me the legal Fatwa in this regard. May Allah reward you with the best!

A: There is no impediment to build a Masjid under the house, if the original construction was designed that way, or a space under the house was later allocated to be a Masjid. However, if a house is planned to be built over an established Masjid, then this is impermissible because the space above the Masjid falls under its boundaries and is endowed to it. (Part No. 5; Page No. 221) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.