Originally posted by Suzaku:

You can use core wood to make superior support beams, but if you really want to flex your building capabilities, wait until you have access to iron. With that, you can craft iron wood beams and the stonecutter for making stone structures/flooring.

Or there's always the modding route. Just download a mod that disables building integrity requirements and go nuts.

Gotta go for the flex. This is my 1st run, so it has to be pure vanilla.