I'll be calculating the feat all the lower tier Titans scale to. According to the Teen Titans Wiki (so of course it may not be accurate) Cyborg is 6 feet tall exactly. I'm comparing his height to the height of the windows, then making the assumption the windows are squares, and finally multiplying that by how many rows and columns of windows there are to get the length, width, and height and by extension the volume and mass.
2609.088 x 2609.088 x 1739.392 = 11840633070.8 cm^3
I'll assume the building is mostly steel first. Steel weighs 7850 kg per cubic meter.
118406330.708 x 7850 = 929489696058 kg
80% hollowness assumption reduces that to 185897939212 kg
Thanks to angsizing I know he swung the building 19 meters and thanks to Premiere Pro I know he did it in 25 frames at 30 fps.
0.5 x 185897939212 x (22.8^2) = 4.8318592e+13 joules or 11.5 kilotons or Town level
Now I'll assume the building's concrete. Concrete is 2400 kg/m^3
118406330.708 x 2400 = 284175193699 kg
80% hollowness assumption reduces that to 56835038739.8 kg
0.5 x 56835038739.8 x (22.8^2) = 1.4772563e+13 or 3.5 kilotons or Small Town level (possibly with a "+" Idk where we draw that line)
This would affect Cyborg, Starfire, and likely Beast Boy who defeated an exact clone of Starfire.
EDIT: Both values would also upgrade everyone's Lifting Strength to Class G if accepted.