I believe the land asset counts towards the book equity with the same value that you purchased it at, so it cancels out. You lose $8m in cash, but gain $8m in land (which doesn't depreciate--that's the key part of the question).
By contrast, the renovation doesn't result in a physical "renovation" asset that the company can say it holds... Therefore the $5m cost for that is subtracted from book equity without being replaced by anything.
That's how I see it, anyway.