reinforcement and Foundation not working

[LunaCat]

I tried Reinforcement and Foundation on the large room after it almost flooded and it won't let me place them. I also have trouble getting up those three steps in the large room.

[Amrak]

I had a hard time placing the reinforcement as well. The Lg. base is kind of fickle so you have to place everything just right. I was able to get 2 on it. Building a bulkhead will also add to reinforcement. Just keep trying till you hit it just right.