Question :
I work for door company. Is selling doors to non-Islamic banks permissible?
The Answer :
All perfect praise be to Allah, The Lord of The Worlds, and may His blessings and peace be upon our Prophet Mohammad and upon all his family and companions.
Works that facilitate usurious transactions in non-Islamic banks are forbidden to be carried out, and since your job(Asker) in the above company has nothing to do with Riba(Usury/interest), then it is permissible. And Allah knows best.