In short, yes it is unless you are talking about that fanfold stuff. For best results you should consider two layers with offset seams as all materials do expand & contract. Not only will this decrease your heating & cooling loads but also help reduce air leakage & noise transmittance (if done properly). One other item to consider is utilizing rain screen technology where you leave a gap between the foam & siding allowing things to dry out For more on this - http://thehtrc.com/2013/common-sense-weather-resistive-barrier
Worth adding foam if I'm replacing cladding?
Worth adding foam if I'm replacing cladding?Asked by Alan
We have 1971 home zone 7/8. We will be replacing the cement board siding and adding a story. The walls are 4". Is it worthwhile to add exterior foam sheathing while we are at it?