Can you lien a church in the state of PA?
Yes, a church would be treated as any other private construction project would under Pennsylvania's mechanics lien laws. The deadline to file a lien in PA is 6 months from the last date that the claimant provided labor and/or materials to the project. But keep in mind, that if you are a subcontractor (or any other party that didn't contract directly with the property owner) a Notice of Intent to Lien needs to be sent to the property owner at least 30 days prior to filing a claim.
For more information see: How to File a Pennsylvania Mechanics Lien | A Step-by-Step Guide
Yes, there are no specific exceptions for churches (or other non-profits for that matter) under any state mechanics lien laws. At the end of the day, such organizations are almost always privately owned, and thus subject to the applicable lien laws of that state.
Generally, the only distinction regarding whether a lien can be filed on a property or not is whether the property is owned privately or by a public entity, or if the private project has a payment bond posted. (with some gray area concerning Public- Private Partnerships (P3s))