My bedroom is in an A-frame with only 8" rafters. The slanted walls contains fiberglass insulation and is drywalled. The room gets cold. Can I simply apply 2x4s against the existing wall, put fiberglass or pink insulation board between the new studs and put drywall over it?

Should I remove the existing drywall?
What about vapor barrier?
Will this make a difference in keep the room warm?

Thanks,

Glenn

It will make a difference but you run the chance of a double vapor barrier (big no no). You need to see what is in the existing cavity. A pro woud remove the old drywall and any vapor abbrier. Then install 2x4 to incraes the cavity, add insulation, staple new barrier and then drywall

Look outside to see if there is a ridge vent and soffit vents in the existing roof. Without good ventilation you'll get ice dams.

Try a ceiling fan on low to bring the hot air down from the peak.

Radiant floor heat is probably your best coice with a high ceiling. The heat is right where you are.

The outer walls are made of?They can be addressed also.

I live in a converted barn with board and batten siding(1X12's spaced apart and a @2" batten over the spacing,there are cold moments.)I applied caulk(high grade,urethane based)to the west wall last fall to test the product,and to see if there would be a noticeable change in the heat loss/cold penetration.

Huge difference.

I have yet to see how the clod winter and spring thaw will affect the new caulk.If there is little problem with it,the rest of the barn(Approx @26 square of surface) will be addressed for the new year.

It might make more sense to look where the cold is coming from rather than trying to block it after it has already penetrated the outsides.