I'm trying to make the Off-Grid Home as energy efficient as possible. Partly because we want a comfortable home but also because the less energy we need to heat and cool the house, the less solar power we'll use. This is important when we get several cloudy days in a row or at night when we're pulling power from the batteries and have a limited amount.
I've learned that running the header boards through a plainer will save you a lot of headaches down the road. Often times the wood you are using is warped and by the time you put two or three together that warping could make your headers off a quarter inch or more. Using a plainer makes them flat when putting them together and hopefully they'll stay that way and not warp again later once installed. This is why I put A LOT of nails when putting them together.
Wood has around an R-1 insulation value. This isn't much compared to the insulated wall with an R value of at least 13 or greater. This means that your headers will always be a hole in you insulation envelope. To combat this, I put some rigid insulation between the wood. In this case, I'm using 1/2" rigid foam with an R-3.5 value. So I have 4.5" if wood equaling R-4.5 plus two sheets of the foam equaling R-7 for a total of R-11.5 and we'll add R-.5 for the sheathing for a total R-12 header. I'm also planning to put 1" of rigid foam on the outside of the sheathing which is another R-6.5 giving me a total value of around R-18.5.
Another way to get a nice straight header is to trim the top and bottom down. I'm using a table saw to accomplish this, which is tough since my header is a bit large. Doing this ensures that my framing above and below the header will be level and straight which makes everything easier.
June 2020