Like many builders, I made my turtleback 1.5″ taller to provide more room and a better fit to a slightly larger canopy. This caused me some grief, though. There wasn’t time to do the layup after installing the foam, so I left it overnight. Well, apparently the humidity and cool evening weakened the 5-min epoxy hold where I had to lengthen each piece. The joints were at the ends, where the curve is the sharpest, and they just snapped overnight. I spent all evening Thursday repairing them, and here’s hoping it will hold, because I can’t get back in there until next week!

A few things would have prevented this, and I strongly encourage other builders raising their turtlebacks to do one or more of the following:

1. Install more slats. The plans number of support slats is just barely acceptable , and when you raise the height, it puts you over the top. I recommend at least 2 additional slats per side, more closely packed the farther you go up the curve. They’re VERY fast to install, especially if you cut their slots when you cut the rest, and could save you a lot of heartache.
2. Make sure the flashing that supports the edges of the foam pieces is firmly attached at every spot, and especially at the top, where if you simply tape it, the tape may peel off the duct tape lining. I had used a roll of aluminum foil tape that John had lying around, and it was great at first because it was so thin, and held its position. The problem was that it didn’t stick very well, so it gave way at the top and was part of what allowed the foam pieces to buckle.
3. Don’t do the joints at the ends. You want them even, on both sides, so you don’t get a noticeable line on one side but not the other, but that doesn’t mean they have to be at the lip. Instead, cut each foam strip in half in its middle and add the extension piece there. There’s not much flex in that section, so you don’t have stress on the j0int, and if you’re careful to use very little glue, you won’t get a joint line (it’s easily sanded, anyway).
4. Use twice as many foam strips. This is probably annoying, but if you used 3″ strips instead of 6″ strips, they would be easier to shape for a good fit and install. You’d also need more flashing, of course, but by the time you were done you’d probably be ahead of the game.