I've opened up a lath and plaster of a non bearing wall in my home built in 1924 (had a structural engineer look at it to confirm) but only partially - 5" under the molding (10" height). This molding I would like to keep. Also, due to electrical wires/outlets that are still needed, I would like to keep the wall as a U shape opening with lateral widths of less than 12" (as slim as possible without becoming an eye sore). Studs are 2"x4" at 12" on center.
The structural engineer said that I don't need a header to support the teeth studs that will result from the opening. Is that true ? The opening is rather large, over 10'. To be safe, should I still put a header? If so, what would be the minimum height I would need.
Edit: I remembered I had a photo taken while taking the plaster and lath down.