Glad I read this thread. I just rebuilt my garage doors bottom panel with a 2x6x14 pressure treated bottom, a 2x4 top and 2x4 verticals with wood panels. The panel weighs twice the original and the spring are just off of being able to hold the weight. I was thinking about ripping it apart and using lighter materials. Instead I will have the springs replaced. I'm sure theyre at least a 15 yrs old anyhow. In addition they're attached to a 2x6 nailed to a joist. Doesn't give me a warm fuzzy feeling seeing it.