Nov 15, 2011
Yesterday, a team of us went out to see a cluster of small camps in a south Atlanta suburb, to make a few repairs and ensure that people would be able to weather winter safely. While out there, we saw two recently built structures with easy-to-make construction flaws, the types of things that can happen when you're inexperienced or you're moving too fast and get sloppy.
I'm not showing these to shame the folks who built them; in each case, there's a way to correct the errors, and we'll go over them. Instead, these mistakes illustrate two important principles: first, that minor mistakes can have major consequences; and second, that minimal design can give you the flexibility to adapt your structure to its environment and recover from mistakes easily.
Mistake one: forgot the insulation.
Our Low Rider shelters are to small to put a heating source in safely, so the sleeping units are built with rigid insulation incorporated into the panels. However, one Low Rider deployed into the field was built by students and didn't have the insulation. As a result, the client is looking at a winter sheltered only by 3/8" plywood walls with no heat source.
Solution: Rock 'em Old School
These days, our insulated panels are built stud-insulation-plywood - the insulation is faces the client, nailed into place between the plywood and the lumber. We wrap the client-facing side of the fragile insulation with house wrap to protect it from being shredded accidentally by the client.
However, it wasn't always that way. Before we moved the insulation between the stud and the plywood, we used to build the sleeping unit panels with plywood and stud and put the insulation on the outside of the structure, like a jacket. Over that insulation we'd add another layer of thin plywood, to make a sandwich:
There's nothing wrong with this approach, it's just heavier and more expensive. In fact, for colder climates, it's probably a more suitable solution, since you'd be able to work with thicker sheets of insulation more easily. But for Atlanta, moving the insulation inside made sense. For this particular Low Rider, however, we'll be bringing out rigid insulation and additional ply to jacket up the client's Low Rider. Problem solved!
Mistake Two: The Backwards Roof
Another structure, a hi-hat, had its roof on backwards. What's that, you say? How can a roof be put on backwards?
Well, a Hi-Hat's roof is asymmetric - it's higher on one side than on the other. And the asymmetric gables of these