Research "Refined Renovations" then you can find them in Base menu.
If there still nothing ,try turn off other mods see if any conflict.

i have the whole research tree aside from rocketry unlocked, i'm looking at refined renovations right now and it's not there. What kind of mod conflict would make it so that only refined renovations is missing 1 building?

引用自 Mahskie：

i have the whole research tree aside from rocketry unlocked, i'm looking at refined renovations right now and it's not there. What kind of mod conflict would make it so that only refined renovations is missing 1 building?

Tell me if you found any MOD cause this issue, so i can try to fix this.

? there hasn't ever been any other mod i've had that has had this issue, i dont know what else you could mean by that

引用自 Mahskie：

? there hasn't ever been any other mod i've had that has had this issue, i dont know what else you could mean by that

I'm not mean other mod also has this issue.
But if there is conflict, that must be 2 or more mods interacting each other.
So you can try disable other mods or change the load order, see if the stairs appear.
If you locate which mod is taking the part of this issue , I can try to deal with it .

@Mahskie: I just started playing this game again, and found I had the same issue as you - scaffolding just didn't appear, either in the research or build menus. I tried removing my mods one by one but even when this mod was the only one installed, I was still having trouble.

Turns out the mod seemed to be using old files from before the update, and had not downloaded the latest patch. I turned the mod off in game, then unsubscribed to it in the Workshop. Then I went to the following location on my computer:

C:\Users\*USERNAME*\Documents\Klei\OxygenNotIncluded\mods

In there I deleted the folder 2012810337 (the mod ID for this mod) to remove all the old files. Then I subbed to the mod again and let it download anew, and let ONI restart to activate it properly. Now the scaffolding shows up as it should, and the stairs are using the new icon from the screenshots, not the old square one they used to have.

Hope that helps^^