Expert: Bruce E. Johnson - 7/8/2009

Question
I am planning out a bathroom remodel. We are moving the location of the jetted bathtub to a location where the long side of the tub runs perpendicular to the 2x10 floor joists. The room is 17'3" x 6'7" with the long side of the tub on the long wall. I need to determine the live load to make sure the span of the floor joists are not too long, requiring some structural enhancement.

Assuming the following:
1. The dimensions of the tub are 70"x36"
2. The weight of the tub with water is 700lbs

How do I calculate the live load?

Thank you!

Answer
Hi David, it's quite simple really you take the weight of the filled tub 700 pounds and divide it by the square footage of the tub which is approximately 18 sq feet.  Which is 39 pounds per square foot.  Most standard floor systems will support a filled tub without any problems.  Most tubs are located near a wall which means that you are closer to the bearing location of the joists and closer you get to the wall the stronger the joists are.  I hope this information helps, feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com