Can I put a 120 gallon upstairs without worrying?

[toxic111]

Originally Posted by Delphinus

Problem is you can't always assume that all joists run in the same direction. At least in my house for example there's about a 4'x6' section in my living room where the builders all of a sudden changed directions perpendicular to the rest of them.

By the sounds of that there was probably a cantilever there. One of the reasons to switch joist directions.

I have built houses though that joist directions switch several times. Back in the day of limited spans of 2x10's it sometimes the only way to do things.