Deep Energy Retrofits: The Problem Areas
I love following this story, notably because I’ve been doing the same thing to my own home for the last several years. And I think remodeling existing homes is about a million times greener than building new ones. Anyway, my house is older and of a different construction type (terra cotta block) than Jeff’s, but we’re dealing with a lot of the same things, including rotting wood as shown here.
I like that we get to see the guts of the house–this is where the action is. And nice detail is explained here:

- Deep Energy Retro-Fit–Wood Rot
This image also illustrates how sheathing (the outer layer of a building’s framework) was applied in the 1940s and why buildings from that era are so drafty. As you can see, these 1×6 boards were applied on a diagonal, leaving a decent-sized gap between each board. This allows air to infiltrate the building envelope, letting your conditioned air out and unconditioned air in. This is part of the reason your house feels drafty and dry in the wintertime (cold, dry outdoor air seeping in and your humidity and heat seeping out) and uncomfortably sticky and warm in the summertime (dry, cool, air-conditioned air seeping out and hot, humid outdoor air seeping in).
I want to add to this caption though because I think there’s a lot going on in this little photo.
First, the caption is correct as it relates to air movement, but kind of misses the mark with regard to how houses were built back then. Buildings from the 1940s aren’t drafty because they have 1-by sheathing. They’re drafty because they don’t have any insulation. What’s more, those diagonal sheathing boards (Trivia: anyone know why they were installed that way?) weren’t installed with gaps. When the carpenters nailed them off, those boards were butted together. However, they were probably green (More trivia: who knows what “green” used to mean?). As they dried, they shrunk. That’s where the gaps come from. It’s secondary that air leaks through them.
Generally speaking plywood and house-wrap are a more impervious system to air movement (but not temperature). The plywood creates a barrier with fewer gaps that wind can push through. House wrap holds water out to a degree but lets air pass, enabling the house to breath–very, very important.
Looking forward to the next chapter in the project.
Mark Clement is host of MyFititUpLife and the tool and how-to ace for DIYNetwork.





Turns out a web search for free Southern Pine, Cedar, or Fir was a strike-out. However, it did turn up a couple of