Deep Energy Retrofit of a 100-Year-Old House – Need Advice – GreenBuildingAdvisor

I’m renovating a 2,200 sq. ft., 100-year-old home in southeast Alabama (Climate Zone 3A). The original house has 2×4 heart pine framing, a vented crawl space and attic, R-13 fiberglass in the walls, and deteriorated Masonite siding. A newer addition has 2×6 walls with Visqueen, R-19 fiberglass, exterior foam board, and Masonite siding.

My plan is to remove the old siding and felt, replace all windows, air seal the house, treat the framing with Bora-Care, reinstall the wall insulation without the kraft facing, install ZIP sheathing, continuous exterior rigid insulation, a rainscreen, and new Hardie or vinyl siding.

My questions:

1. Should I remove the Visqueen vapor barrier in the addition’s walls, ceiling, and floor?
2. Does this retrofit plan follow good building science practices for a hot-humid Climate Zone 3A?
3. Is there anything you would change to improve moisture control or energy performance?

I’d appreciate any suggestions before I begin the project.