All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
Al-Buhrah is one of the sub-sects of the deviant Ismaʻiliyyah sect. Their beliefs are the same as the beliefs of the Ismaʻiliyyah, such as believing in the existence of an infallible hidden imaam who is a descendant of Muhammad ibn Isma'il. They also attribute divinity to their imaams and believe in reincarnation of the soul and that the imaam is the heir of all the Prophets of Allaah, and the like of false beliefs. Please, refer to fatwa 89255.
Hence, it is impermissible for the Muslim, an architect or otherwise, to contribute to building a place if he is certain or has a preponderant belief that it will be used in disobeying Allaah and in plain violation of the divine sharee'ah given the general indication of the verse that reads (what means): {...And cooperate in righteousness and piety, but do not cooperate in sin and aggression...} [Quran 5:2] There are many other religious texts to this effect.
Allaah knows best.