"the red big building."
On the other hand, if the most important distinction is its color, I would say
"the big red building."
Thanks, I'll be here all week.
A: What building do I need to go to? B: The big one. A: Which big one? I see a red one and a green one. B: The red big building.
It's worth knowing that I'm a pure mathematician, and I frequently come out with utterances that others find odd, purely on logical grounds. It's plausible that there are circumstances in which I would violate these rules/guidelines/suggestions/baseless musings/whatever.
That's not one of them.
It's as if linguistics is often modeling syntactic rules which reflect something other than natural communication as it actually occurs.
And in your particular case, where we want to also tell it is big, we do: The big building red (Le grand bâtiment rouge)
But we can't do the following: The red building big (Le rouge bâtiment grand)
Different language, different grammar :) French is one of the most difficult language for these I think, a bunch of exceptions. It makes the language more "lovely" to hear but less "effective". Here we say English is made for business, it is one of those languages that just gets to the point fast and clear overall :)
For example, ma propre chemise vs ma chemise propre (my own shirt vs my clean shirt). Or mon cher ami vs ma chère chemise (my dear friend vs my expensive shirt).
BTW I would be interested to read if someone shared his experience.
The other hard part of learning French (for me) was the conjugation of verbs in various tenses, and specifically any words that are exceptions to the normal rules. If you take a look at a french grammar book for (e.g.) English speakers, it's likely that it will mostly concern conjugation.