Originally posted by PhotriusPyrelus:

As a follow-up, is there any way to build supports down from flooring? Because I can't figure out how and it's kinda frustrating. =-\

Outside of one or two mods, not any particularly easy way.

Though, as Suzaku said above, there is a patch in the works that essentially brings something like those mods' functionality into the vanilla game. Only question is when it'll be released.

(The mod I'm particularly thinking of is Snap Points Made Easy[valheim.thunderstore.io], if you're interested. Simply ignore if you're not.)