Does anyone have recommendations/opinions on well-insulated garage doors? I see that many manufacturers have R10+ doors, but are their weatherstripping methods effective to make the higher r-value efficient? Attached 2 car garage (icf walls) will have attached workshop (20'x22') space and living areas above. Thanks in advance!

I used Raynor Centura doors for my project (R18).  They are good.  In my opinion, they are worth the money.  They do seal tightly.

My garage is also below living area.  My garage is not heated, and is well insulated from the remainder of the house with closed cell spray foam.  During the cold winter months, with the doors closed, the garage space will approach ground temperature.  The uninsulated garage slab provides a constant 40-50F.  Not warm by any stretch, but a nice buffer when the outside temp is in the single digits.

Hope this helps.

Regards,
Ed  

Thanks for the replies. That answers my questions pretty well. All that I would really want is that there be a buffer between the outside and living space that could maintain +/- 50F and could be brought up higher with space heating. Have you both experienced moisture issues in your garages? If so, how did you solve it?

Personally, I have not experienced moisture issues, but I don't really have a source of moisture either.  Under the slab is a layer of thick plastic, and the foundation is well sealed.  The cars never run with the doors closed.  I do not work in the garage very often (I have a fully conditioned shop area).   

I guess the most obvious source of potential moisture would be snow-covered cars in winter. If there is a floor drain, not sure how big of an issue that would be, apparently for you, none at all.

Ah, true.  That is one source I didn't think of.  Still, the most I've ever seen is a little condensation on the windows (they are obviously not R18).  Not enough to call it a problem. 

During the past month when temperatures got down in the single digits, I noticed frost forming on the inside of the garage door windows. A few other houses in the neighborhood were experiencing the same frost buildup. I checked the relative humidity and found it to be around 60% @ 40 deg F. I had the garage doors closed all the time and would open the door to main house when working there. I assume that moisture from my breath and from the house built up in the tightly constructed garage. Now I make it a point to open the garage door now and then to ventilate the space. Seems to have remedied the problem.

open the door once in a while.....low tech....I like it!