westend wrote:
You were doing pretty good until you got to the above paragraph. I've installed a lot of square feet of different engineered plank systems. I've installed in basements, in Hawaii (open patio door 1 mile from the beach), and in dozens of other homes where humidity is not controlled like you state. I have never seen a failure due to excessive humidity. As for controlling humidity underneath, that is part of the purpose of an underlayment or a plank that has an attached back. It is usually a caveat for basement installation.
The manufacturers state that a warranty is void if not maintained between 30-50% or close to that (some CYA to this of course). It's not just the humidity level as I understand it (and if the material is acclimatized before installation), it's the wide swings in humidity and how often and how quickly (as well as the thickness, wood type and/or quality). The flooring also has less chance of damage if it is installed/used in a humidity level close to what it was in the manufacturing plant. I know this flooring gets installed in basements and high humidity areas lots but I think what helps it is that once it's installed, the indoor humidity and temps (ground temp. is quite stable) normally don't change a lot and as much like they would in an RV, and the humidity level of the top and bottom of the flooring isn't that much different. While an entire floating engineered floor will shrink and expand with humidity, because the veneer layer is a different species, it can shrink and expand at a different rate depending on the species and humidity differential resulting in cupping.
The worst case might be in the winter if you're in a cold/dry climate and take your TT out for a camping trip and suddenly generate a lot of moisture inside from cooking, showering and from bodies creating a large humidity differential in the wood which then quickly changes again when you go back home. If the differential rises above 20% between indoor RH and humidity level of the floor, that's when damage starts to occur.
Anyhoo, I couldn't find any opinion from any flooring experts on google for engineered flooring in TTs or feedback from TT owners and everyone basically recommends vinyl laminate over any type of wood flooring product.