Shear Wall in 100 Yeal Old House
I am remodeling a house build around 1910.
Wall configuration from inside to outside: Plaster, ship lath (sp?) 2x4 studs with blown in insulation in the bays, wood lap siding, some type of asphalt siding, and vinyl siding.
I have removed the interior plaster, ship lath and insulation in approximately 1/2 of the house.
* What I am calling ship lath = approximately 1" thick tongue in groove wood boards that were attached horizontally to all opened up exterior walls on the interior side only.
My original plan was to remove all exterior siding down to studs and attach new plywood, add foam boards and new exterior siding.
My plans have now changed to - finish interior, add new windows and replace exterior vinyl.
My question is -what to do about structural integrity of exterior walls?
I read an article about creating "insert shear panels" by making panels out of 2x4's and plywood and inserting them between the wall studs.
This seemed like a lot of work, but a possibility as I am considering insulating as follows: 3 layers of cotton batt (first layer: in 2x4 exterior wall, 2nd layer: between exterior wall and new interior wall, 3rd layer: in new 2x4 interior wall. This would be finished with Dry Right (by CertainTeed) and then sheet rock over it. I was thinking the plywood would also block some air flow as there is no plywood on the exterior of the house.
The second option would be to insulate the original exterior wall, attach 1/2 - 3/4" plywood to the interior (where the ship lath was originally attached), apply Dry Right (by CertainTeed) and then sheet rock over it.
I know that would be alot cheaper, but I am very tired of being cold in this old house.
Any suggestions? All would be greatly appreciated.