Hello, I am planning to replace the siding and add insulation to turn a 3 season cottage to 4 season. The current wall is drywall with poly vapour barrier, 2x4" framing with fiberglass. The sheathing was 7/16 asphalt sheathing with an exterior stained plywood on top (with batten strips).
We have restained it several times over the past 35 years. (Dad originally built it) I was thinging I could just remove the batten strips and then wrap with WRB (Delta Vent SA or similar) and then add 2" of EPS and then vertically strap for Rain screen and put vinyl or wood siding on top. My question is whether I should be removing the old plywood and asphalt sheathing and possibly the old insulation. and reinsulate and sheath. As well should I be putting the WRB barrier on the sheathing or the outer rigid insulation? Lastly, when adding a rain screen, I assume insulated vinyl siding would be of limited insulation benefit...correct?
Thanks, any input would be appreciated.