Energy Efficient Door & Window Headers
With a continued focus on energy efficient construction (Green Construction) we are always looking for ways to improve upon residential construction techniques. Insulated door and window headers are one way to improve
on standard framing methods.
Old School Headers
Years ago we used to build door and window headers by creating a sandwich of five pieces of lumber (for a 2×6 wall) consisting of three pieces of 2x material (depth depending on load) and two pieces of 1/2 inch plywood. The idea was to create a header that was 5-1/2 inches thick. The end result was a very strong header with very poor insulating properties.
For one of our current projects we’re using an insulated header. Over the last few years we’ve used several different insulated header types. On the current project we’re using a header that replaces the two layers of 1/2 inch plywood with an inch of DOW polystyrene insulation. The one inch of foam board insulation (XPS) provides approximately an R Value of 4.5 to 5.0. This particular insulated header is on the lower end of what is possible.
Other versions of the insulated header that we’ve used include headers that use only two outer structural plies (typically upgraded to an LVL due to loading). This increases the insulation in the center to approximately 2-1/2 inches. The insulation can be either XPS for an R value of 11 to 12 or a layer of Polyisocyanurate for an R value of 17 to 20.
This type of insulated header poses some problems. As you can see the header needs to be built with a partial “box” in order to hold it’s shape and retain the insulation. There are two problems with this design:
- Sometimes the loading is too great for the two structural layers.
- The depth of structural layers is limited by the horizontal piece at the bottom, thus further limiting structural capacity.
Insulate Headers For Energy Efficiency
The lesson here is to improve energy efficiency in new home construction by paying attention to small details. Insulated headers might not seem like a big deal but every little bit counts. I’m sure there are even more variations on these examples so if anyone has others please share.
Insulated Header Video
I shot a short video from a job site showing another version of the insulated headers over some windows.