R19 Walls or better?

[rwalter]

I have pretty much already made up my mind but I just wanted to see what the rest of your opinions are on the lumber size to use for framing walls. first off The cabin I am planning on building is in Western NY so it gets pretty cold here. I pretty much set with using 2x6 lumber in my designs and R19 fiberglass faced battens. (I had my addition on my house framed that way.) However the other day I was talking to my wifes uncle who is the building inspector for one of the local towns around here and he said to go with 2x4 walls and just use foam board on the outside to reach R19. He stated the cost of the foam board insulation would bed be cheaper and easier to apply than building all the custom jams for all the 2x6 walls with windows and the doors. I am not planning on having a ton of window. Whats is everyones take on this. Or should I go higher than R19? I realize that the studs are the weak link in any wall and the foam does help reduce that aspect. I seen where people super insulate houses using a inner and outer 2x4 wall system and I'd love to offset two 2x4 walls on 24" OC but I don't want to give up the space or spend the money where its not needed. What's your thought on this?

[John Raabe]

In your climate I would think R-19 would be a minimum. Out in Western WA (much milder) it is code minimum and almost everyone meets it with 2x6 framing. All the prebuilt doors and windows come with casings for that size wall.

However, 2x4 walls can be just as good if not better. In the Enchilada kit (http://www.jshow.com/y2k/listings/43.html) there is a detail that has been used around here for many years. It is nicknamed "the poors man's SIP" as it builds a wall similar in performance to the more expensive structural insulated panels. It uses 2x4 framing and foam insulation on the interior side to work as a moisture and air barrier as well as getting the wall up over R-23.