Ok I need some one to help answer a question.

I have a friend that is telling me if I put 2 X 2 over plaster and lath and then put regular bat insulation between them and then drywall over that it will work perfectly and will not lose any R value by smashing it into a 1 1/2 " area as opposed to a 3 1/2" area.

He stated he did that and it worked perfect. He did it as a poormans remodel.

Which is true? Do you lose R Value if you smash it in a smaller area or does it keep the same R value?

Your friend is wrong. Air is the insulating factor and by compressing the fiberglass you lose R value.

Your friend is wrong. Air is the insulating factor and by compressing the fiberglass you lose R value.

Thank you. That is what I told him but he said otherwise. Now I have proof.