Best Insulation System, Home Wall and Roof?
"Stick-built" wood construction requires a cage of "studs" (vertical 2x4 or 2x6 beams) at regular intervals for structural support. The later insulation problem is:
- The studs "go through" the typical insulation (inside wall to outside wall) and bleed heat to outside like fins on a radiator.
- Each rectangle (between studs) is its own insulation project with a full perimeter to be sealed. Not sealing the edges is like installing a high-tech super-insulated window and then leaving it open.
Your actual heat retention is not the advertised R rating of the insulation material, your "effective R value" is the "full wall" result of the entire system. You can check insulation without opening walls by measuring drafts (air leakage) or measuring temperature with thermometers or infrared (IR) cameras' thermograms (thermographic inspection).
Quick Tip: All else being equal (same sun time, etc.) , a roof which keeps its snow longer is insulated better than the roof next door which melts it snow faster from below by heat leaks.
I currently do not favor stick-built construction because every edge is an enemy to insulation. I currently am looking for solid information on the effective R value of an earth-sheltered solid-concrete construction with external foam board insulation. I also seek information on the value of radiant barriers and reflective paint (please leave a comment with tips).