Insulation, Radiant and Vapor Barriers - insulating with tyvec inside

Hello there
After removing an interior/exterior wall i saw that there was nothing between the siding and the wood on the outside. It isn't plywood but 6 inch board. Can i put tyvec on the inside and than cover the space in with plywood between the inside studs and than use insulation. I didn"t really want to take off the siding.
In advance thanks for your help
Isetheby

Tyvek's main purpose is to act as a breathable building paper, which is installed on the OUTSIDE of the sheathing with as few seams as possible. Tyvek (with a K) can also be an effective air barrier when all edges and seams are sealed with Tyvek tape to prevent air infiltration. Tyvek has no r-value of it's own, so just putting Tyvek in the walls will not make your home any warmer. You would have air leakage around the perimeter of every 14 1/2" wide strip of Tyvek, so doing it that way would not keep much air out at all.

If you already have building paper (such as felt / tar paper) under your siding, there is no need to remove your siding *just* to install Tyvek. Insulate your walls, and install a visqueen (4-6 mil poly) vapor barrier over your studs. Spend your time insulating and air sealing the visqueen (taping all seams) before you drywall and that will be time well spent.

I'm not saying this in a rude way, but putting Tyvek in between your studs would be a complete waste of time.

Thanks a lot for the info. Appreciate it.