[cmartin]

Thanks all, good info. I'm still reading about the options and hope to put together a few options depending on what I find and how much $$ is available.

Here's another option I hadnt thought of, rigid foam and spray foam.

http://youtu.be/i1guAwzyEOQ

[BlackTalon]

As with any wall insulation in the DC-metro area, a vapor retarder should be installed on the interior side.

[cmartin]

According to the spray foam vendor, the spray foam should be the outside insulation. So, if applying from the outside, rigid foam against the drywall, then sprayfoam then sheathing.

Was reading on the vapor issues of each insulation type, seems there isnt a simple answer to any of this. As mentioned above it seems fairly common to have moisture issues in the insulation when using an exterior moisture barrier and/or foam.

Not quite as simple as I expected.

[BlackTalon]

If spraying over board insulation, I would be concerned about condensation and would make 100% sure there was a vapor retarder installed prior to the board insulation. Otherwise good chance condensation could occur in the board layer, resulting in moisture build-up inside the wall cross-section, and potential deterioration of wood framing. (And I'll skip the M word for now -- it's pretty overblown, although it can lead to problems if there is little air movements and a constant moisture source).