On Sat, 09 Aug 2008 22:33:34 -0400, mm
wrote:

I've looked for a definition on the web and it seems that T1-11 is
hardboard. But I've also seen it called plywood. Which is it?

Wow, there was a lot more to this question than I thought there was.
That's often the case. I'm glad I asked. Thanks, guys.