Another example of building out a wall to beef up insulation is a project we took on a couple of years ago to beef up our entire north wall. The rooms on the north side of the house were always somewhat uncomfortable in the winter. So, one summer, we dug a trench to the bottom of the foundation of the north side and added Roxul; a lightweight, semi-rigid stone wool insulation that is also water proof and fire resistant. It also provides excellent sound control and is often used in sound booths in the voiceover industry (see Swati’s aka Essie Bartosik’s voiceover studio)!
One problem that building out exterior walls often present is that if there is insufficient overhang, then the roof has to be extended as well. In our case for approximately 25′ there was no roof overhang, so we added a faux roof.
Adding New Insulation- Below Grade
Digging a trench 
Bituthene (water-proof membrane) on 
1st layer of Roxul insulation 
2nd layer of Roxul 
Securing two layers of Roxul 
Roxul is secured
Adding New Insulation- Above Grade
Henry Blueskin; a breathable weatherproof air-sealing membrane 
4″ of Roxul installed on top of the Blueskin
Adding a Faux Roof
North Side Sans Roof 
North Side With New Faux Roof
