Expert: Bruce E. Johnson - 10/25/2009

Question
We were given a large fish tank and want to make sure it won't fall through the floor to the basement.  The tank is ten feet long and holds 300 gallons. We estimate it to weigh 2500 pounds. Please answer as soon as possible. Thanks!

Answer
Hi Kristen, without knowing what size the floor joists in your floor system and how long they span makes it hard to comment properly.  Considering that water distributes its weight evenly over an area you first need to figure the square footage of the overall tank.  If it is 10 feet long and 2 feet wide that would make its footprint on the floor 20 square feet so that the weight per square foot is 125 pounds.  If the tank is placed along an outside wall or close to a bearing wall then the joists will handle the weight better than if the tank is placed in the middle of a room or in the middle of the joist span.  I hope this information helps, feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com