Re: OLD house in need of paint
The vapor barrier goes on the warm side of the building envelope, not directly under the exterior siding (unless you literally live in the tropics). In N.A. placing vapor barrier under siding results in wet insulation and probably wet framing, mold and eventually rot/structural failure.
Almost as bad a situation can be created by putting a second sheathing over the original, or tarpaper between sheathing and flush siding.
Instead, we use a houswrap that is wind-proof, liquid-water-resistant but water-vapor-permeable. That' s a Tyvek or Typar (to name two brands).
Remove not the ancient landmark, which your fathers have set.