Ok. I finally air sealed and insulated my living room. Now comes the question of a Smart Vapor/Air barrier.

Details
My house is 86 years of age. It consists of three exterior walls and one interior wall. Semi cathedral like ceiling with tray ceiling.

ECC Zone: Between 4/5

Wall one/ Wall Two: True 2 x 4(old) construction, 3/4 Celotex tar impregnated sheathing, old brownstone masonry. All cavities air sealed with spray foam and acoustic sealant. Rockwool R15 insulation. I did use Delta Dry in several areas where the Celotex was rotted(Cut it out and spray foamed Delta Dry in it’s place.

Wall three: 2 x 4 construction, 3/4 plywood siding, Tyvek house wrap, Vinyl Siding. All interior cavities sealed with Acoustic sealant and spray foam. Rockwool R15 insulation. All wood joints sealed with acoustic sealant.

Sloped part of wall/ceiling: R5 one inch XPS with one inch air gap. All joints sealed with spray foam. Rockwool R23 insulation.

Ceiling: 1/4 inch plywood.

Roof: 6yr old Architectural Asphalt Shingles, Tar paper and ice/water shield, 3/4 exterior plywood deck. Vented with roof ridge vent and rafter vents. Insulation R38 blown in cellulose.

The Finish: 1/2 or 5/8 sheetrock primed and painted. Pitched walls/ceiling 5/8 sheetrock and 1/4 inch nickel gap paneling. Sheetrock on the tray part(going over the existing 1/4 inch plywood).

So with the details out of the way and some attached pictures. Do you recommend a smart membrane? I’ve looked at Membrain, Intello Plus, Siga Majrex, and Rothoblaas Clima Control 80. I don’t know what is better for my needs or if it even makes sense. The big problem is along the fireplace wall. there really is no good way to seal it along the fireplace in certain areas. Also I’m not sure there is a good way to seal the pitched part where it meets the ceiling. I suppose I could overlap the product where it meets the ceiling. I hope I have provided enough details. Thank you for helping me out.

Images:

https://photos.app.goo.gl/r9JA5ToakHSVtMxg7