>Perhaps most importantly, the densified wood is also moisture-resistant: In lab tests, compressed samples exposed to extreme humidity for more than five days swelled less than 10 percent—and in subsequent tests, Hu says, a simple coat of paint eliminated that swelling entirely.
This is an improvement, but it doesn’t appear to solve the fundamental problem: rain. In practice most structural materials must survive exposure to not just humid air but liquid water — this is why Sorel cement is not used in construction, for example.
Wicking can be a bitch, and some wood products do not bounce back. Wet a 2x4 and as long as you dry it before rot sets in, good as new. Fiber board, at the other end of the spectrum, ruined forever. There are a lot of things in between.
So they said paint prevents swelling but they don't say what happens to the swelled wood after it dries.
Some woods are ok with rain - I've used cypress for outdoor signage for instance and it takes rain well - no warping or that sort of business. If you constrain expansion to one or two dimensions it might be ok.
This is an improvement, but it doesn’t appear to solve the fundamental problem: rain. In practice most structural materials must survive exposure to not just humid air but liquid water — this is why Sorel cement is not used in construction, for example.