Where is I?tikaaf to be Observed when a Masjid has been Demolished?

Q: It'kaaf-16: Although we had a Masjid in the area, it has been demolished and salaah now takes place in a Madrassah. Can I'tikaaf be observed there and will this be regarded as the sunnah Mu'akkadah I'tikaaf?

Answer: if it is not possible to observe the I'tikaaf in the demolished Masjid, it should be observed in another Masjid in the area and I'tikaaf in the Madrassah will not be valid. However, ii there is no other Masjid, I'tikaaf in the Madrassah will be valid, Inshaa Allaah. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.3