I have an older house built in the 40's with 12 inch beveled cedar siding. Under this is the old traditional 3/4 inch shiplap. Over the shiplap is tarpaper. I have noticed weeping and dark stains on the siding and would attribute this to probably no vapour barrier. What can be done, if anything, to help solve this problem short of gutting every inside wall removing the wood chips, installing insulation and a vapour barrier ?

Tks.

Is this staining on all sides or just the north side?