Expert: Dan Griffin - 3/17/2009

Question
I have a king sized, hardside waterbed which weighs upwards of 2000 lbs including frame. It sits on a 5' x 6' support platform. I have had the bed now for over 4 months without it crashing through the floor. The bed in the corner of the room.

The house we live in is a 1890's Philadelphia 3-story rowhome with 9' ceilings on the first floor. I don't hear any creaking or see anything unusual but I am nervous nonetheless.

Any suggestions?

Answer
Addison, if your numbers are correct you are placing about 67#/SF.  Current code in a sleeping room asks for 30#/SF.  Is there any way to know what size the joists are, how close together, and how far they span?  The very fact you already have it installed says your floor must be overbuilt.  I would not envision a sudden collapse, I feel there would be plenty of signs of problems - cracked plaster, split joints in drywall, sag in the ceiling below.


Is there a way to pull a string line or run a laser on the ceiling below?  I would expect an older place to have some notable sag in the ceiling from time.  L/360 loading (normal code allowance) usually is designed to sag 1/2  to 3/4" as acceptable.  It would have been ideal to have known the profile of the ceiling before the water bed and again after.

If the floor seems solid, the knick knacks and lamps don't wiggle, I would not be very concerned.  It does mear monitoring.  Perhaps an accurate measurement of the ceiling height below the water bed to check once a month.  I wish I could tell you not to worry, but if you had asked me before installing the bed, I would have probably discouraged you unless you knew or determined the floor was overbuilt.