I had a 56 gallon reef tank on an interior wall of a 3rd story apartment one time with over 70 lbs of live rock in it. There is no way your tank will fall through. Rest easy.
i have 450 gallon in the middle of my office on my 2nd story, youll be fine. though my 450 gallon is all on large peice of wood to spread on the weight. though i have many 180's up here also
Residential construction on wood frame is rated at 100lbs per square foot at the weakest point, a 55 is roughly 4x2 or 8 square feet, the tank and water should put you around 600 pounds total weight while the surface area is rated for 800 pounds. In conclusion a 75G tank would be maximum size for the 2nd floor, anything over this size and insurance would not cover as you would be negligent
I had a 56 gallon reef tank on an interior wall of a 3rd story apartment one time with over 70 lbs of live rock in it. There is no way your tank will fall through. Rest easy.
Just remember that his house is residential, office buildings may be masonry and/or steel frame, obviously 200+ lbs per square foot is no problem but for residential anything over 100lbs a square foot is foolish unless on the base floor on a concrete slab