Ain't no way that I'm going to be able to stuff R-38 into the sections where the old roof joins the new, and it will probably get a ding from the inspector unless I address it, so what to do?
My findings so far:
There's a term "High Density Insulation". It seems to apply to blown insulation though. Here's an installation guide for "Dense Pack Cellulose" from a state government:
http://www.incap.org/fieldguide/6%20-%20Insulation.pdf
Certainteed sells something called "High Performance" batts, which look a lot like regular insulation to me. It's supposed to be better, but not enough better according to the chart in the specifications sheet (2nd link).
http://www.certainteed.com/products/insulation/index/317362
http://www.certainteed.com/resources/30211239.pdf
You'd think that styrofoam board would be pretty good, but they only make it up to 4 inches thick, and even if layered it wouldn't quite make it up to R-38:
http://building.dow.com/na/en/products/insulation/deckmate.htm
Here is an unbelievably good guide to the different insulation options, which is my first lead to PolyIso types:
http://www.insulation-guide.com/insulation-types.html
Here's a forum with one answer that also points to polyiso. Note that he claims R=7/inch, so with 5.5" and no ventilation baffle, I cold get R38.5!
http://www.doityourself.com/forum/archive/index.php/t-387868.html
Ok, this is just interesting. I'm sure there's something in this dense blog post about different ways to add R-values. He references the wikipedia article which I found is too general and lacking the kind of dumb table that I'd like to see.
http://sites.google.com/site/phillipnormanatticaccess/Home/insulation-math
Here's an installation manual from something called NRCA. This is interesting because of learning about the existence of NRCA, and that it says to consider polyiso as having a R value of only 5.6/inch and to ignore the manufacturer's Long Term Thermal Resistance rating. It would be sad if true.
http://www.nrca.net/rp/technical/manual/06pdfs/99_100.pdf
Here's a company that makes polyiso. They have a distributor in Baltimore:
http://www.atlasroofing.com/general2.php?section_url=2
Certainteed makes a polyiso that they call FlintBoard, which seems to be commercial oriented. There are further hints that this stuff is intended to be the top deck of the roof rather than under-mounted.:
http://products.construction.com/manufacturer/certainteed-roofing-----low---slope-nst18285/products/flintboard-polyisocyanurate-roof-insulation-nst5378-p
http://www.certainteed.com/products/roofing/308322
Here's a nice web site that is a bit more optimistic about polyiso without providing too many details. They also go into the dual nature of preformed vs. sprayed for this material.
http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11620
Here is a bulletin from PIMA that primarily seems to be oriented towards commercial roofs. But it is interesting to know about the existence of PIMA.
http://www.pima.org/BulletinFiles/tb113_clr.pdf
http://www.pima.org/contentpage/Faq.aspx
Here they talk about muliti-layering polyiso:
http://www.pima.org/BulletinFiles/tb113_clr.pdf
Here's a cute little TOH article that mentions it (with very little details):
http://www.thisoldhouse.com/toh/article/0,,1575422-6,00.html
Here's an article about cape cods. The big panels are nailed on top of the roof in the photos:
http://www.deerparkroofing.com/insulating-ventilating-cape-code-house.php
Here's a TOH article about foam panel. Way down near the bottom, it talks about installing the foam outside of the wall. It does discuss spray-on near the middle.
http://www.oldhouseweb.com/how-to-advice/insulating-walls.shtml
