[Publius6961]

OK I've never used "board-feet" but if I remember right, one board-foot is 1 square foot 1 inch thick.

Assuming your 240 sq. ft. is correct, the answer has to be less than 240 board-ft, since the boards are only 3/4" thick.

So...

240 X 0.75 = 180 board ft.

[Publius6961]

The width of the boards is irrelevant if you know the total square footage.

[Timeout]

Well, that seems right, doesn't it?!

But I think there may be a catch...and I think it's the source of my problem. Some of the lumber websites indicate that board feet is based on the original plank before it's milled....not on the eventual 3/4 in. thick plank.

That seems crazy to me, since one has no way of knowing that. But that's what they said.