I have just finished with removing old insulation and the new doesn't have the moisture paper on the back that is against the drywall once the drywall is up. I have been told that the walls in this den that are on the outside of the house would need a moisture barrier like a 6 mil plastic sheet stapled to the 2x4 studs before drywall goes up.

Two questions

I am assuming that this is pulled tight. Is this correct?

I also after rebuilding one of the outside walls am wanting to put house wrap under the siding. I replace an old window and built the wall to hold two smaller windows. I have all the window dressing but was going to use house wrap also would this be overkill for the Chattanooga TN area or is it ok to use both.

I heard the house has to breathe but I have read different things from different areas. I did goto Lowes and they said that normally you would just need one or the other but could use both an no issues would occur. What is your take?

Area: East TN area ( warm summers, cold to mild winters)