its because Gladiator has tactile telekenetic abilities. The building should crumble under any of these guys. During one of Reed's experiments of testing the Thing's strength where he made an invention that could geometrically increase its weight, Thing held it until its weight caused him to tear through the floor. Actually everytime Reed tries to test his strength, the Thing usually trashes the machine before he reaches his max so not to reveal his limit...maybe thats why he has been under estimated by so many villains i.e. Facade and Doom. Anyway, Hulk has held the pressure of that mountain in secret wars and the weight of a building should be no problem. Thing and Professor Hulk held the weight of miles of stone above them in an issue of Silver Surfer, while in the mole man's caves as well.