I have noticed in our (my and my friends) game that even in late-game most of buildings happens to be built from tier-1 materials. This is because of economic - lower tier is so much cheaper and have no real downsides towards higher tier other than aesthetic; which is very subjective.
Because of it we end up with buildings that are just enough tier to match requirements of working tables inside.
I think this is one of the reasons we never really have had any problems with ecology. That's a shame - that was supposed to be main challenge in ECO and i am starting to believe global warming is conspiracy fake ;P
My proposal is to add any reason for players to use more expensive materials for working buildings. I see 3 options:
1) Working tables should require proportionally less space to function. Something like: requiredSpace = baseRequiredSpace * requiredTier/roomTier
2) Working tables should work proportionally faster. Again something like workSpeed = baseWorkSpeed * roomTier/requiredTier
3) [My favorite] Global count of active projects per player should be limited and over-tiered workplace should lessen this constrain.
Any of those are really game changing: It would be still much easier to build huge tier 1 building. Yet it would give some players excuse to overuse expensive materials and be wastefull.