Scott and crew have made great progress in installing the 4 inches of exterior rigid poly-iso foam (from Iko Enerfoil) around the entire house. They have also attached wooden strapping, using 8 inch timberlock screws to ensure that the foam stays up and to provide a base to which the siding will be attached.
The foam was installed in two layers, staggered so the seams did not overlap, and then taped along the seams. The result should be an efficient air barrier and another R24 of insulation.
Apparently, the strapping was the most difficult and time consuming portion of the work, given that they had to pre-drill 8 inch holes into the studs and screw each screw individually.
The strapping also helps to provide a drainage plain behind the siding to allow water to drain away from the house. I have learned that this is a good way to do siding even if there is no added insulation.