# Waterbed on second floor



## JimMacLachlan (Dec 15, 2014)

That's a complicated question & I wouldn't rely on an answer from a bunch of strangers. The short answer is, you should probably get a local contractor to check it out if you can't find the plans & get an architect to look them over.

I don't know what CA building codes are or how the house is constructed. With as many waterbeds as there are in the country, you'd sure think it would be in a home built in 1998. However, you might find your floor bowing over time. A lot depends on the span, the type of joists & if they used bridging. The last can make a huge difference as it spreads any load over a larger area. 

Here's a pretty good article on where to put a large aquarium. It has a lot of commonality with your issue.
http://www.cichlid-forum.com/articles/aquarium_weight.php


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## ZZZZZ (Oct 1, 2014)

This is just anecdotal of course but I had a king-sized waterbed on the second floor of several houses I lived in for a total of 25+ years, with no problems whatsoever.

I remember reading somewhere that a waterbed has the same load on the floor per square foot as a refrigerator. 

Water weighs 8 lb a gallon, and if I remember right a king waterbed holds about 200 gallons, so the total load is about 1600 pounds, plus the weight of the furniture.


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## gregzoll (Dec 25, 2006)

My sister had one on the second floor of one of her houses, with no issues with it being up there. My cousin also had one on the main floor above the basement, with no issues.


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## Hick (Nov 21, 2014)

As jim noted, its all based on how it was constructed.

The contractor could of just been doing a really stupid job that day. Decided to throw up 2X4 all the way across & simply toe-nail some screws in with a 1/4th sheet of plywood on top. Figuring its "good enough" and if there are any problems down the line its someone else problem.

If it was built properly & to code, you should have no issues. If they just hired some idiot off the street or joe blow decided to mcguyver it himself...you might have a problem.

Hard to really say without knowing what exactly is up there & only way to know that is to have someone look at it. Which will require at the least mild demolition & rebuilding what they had to tear out to get there.

I would however say, 9 out of 10 times. It should be built correctly enough to hold a water bed. Nothing for certain however.


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## talukdar (Mar 29, 2015)

I think waterbed in second floor with weight around 2631 lb is not a good idea, rather you can install the waterbed in ground floor, it will be better for you. 
This 2631 lb all time put pressure on your roof, that's why rooftop may collapse, so be wise and carefully make decision.


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## Dave Sal (Dec 20, 2012)

Had one in my house on the second floor for years. Once I started getting older, sleeping on it made my back sore so I got rid of it. But, never had a problem with structure. My Sleep Number bed is much more comfortable these days. Still, there was nothing quite like getting into bed on a cold winter night with the waterbed heater making everything nice and toasty.


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## Daniel Holzman (Mar 10, 2009)

The fact that someone else successfully installed a water bed on the second floor is not reliable evidence that you can successfully do the same. By the OPS figures, he has 2600 lbs distributed over 30 square feet. This is more than 80 pounds per square foot. Considering that the average bedroom is designed to hold 30, possibly 40, pounds per square foot, should make the OPS at least pause for a moment before filling. Without details of the framing, it is impossible to determine the load capacity of the room.

If you decide to go ahead, check first with your insurance company to make sure you are covered against floor collapse, leakage, or other water bed perils.


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## Dave Sal (Dec 20, 2012)

Daniel Holzman said:


> The fact that someone else successfully installed a water bed on the second floor is not reliable evidence that you can successfully do the same. By the OPS figures, he has 2600 lbs distributed over 30 square feet. This is more than 80 pounds per square foot. Considering that the average bedroom is designed to hold 30, possibly 40, pounds per square foot, should make the OPS at least pause for a moment before filling. Without details of the framing, it is impossible to determine the load capacity of the room.
> 
> If you decide to go ahead, check first with your insurance company to make sure you are covered against floor collapse, leakage, or other water bed perils.


Always good to get an opinion from an engineer. Had I not been so ignorant of such things when I bought mine I probably would have gotten a traditional bed. But, it was the late 70's so how could I pass up a beautiful waterbed.


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## Hick (Nov 21, 2014)

Daniel Holzman said:


> The fact that someone else successfully installed a water bed on the second floor is not reliable evidence that you can successfully do the same. By the OPS figures, he has 2600 lbs distributed over 30 square feet. This is more than 80 pounds per square foot. Considering that the average bedroom is designed to hold 30, possibly 40, pounds per square foot, should make the OPS at least pause for a moment before filling. Without details of the framing, it is impossible to determine the load capacity of the room.
> 
> If you decide to go ahead, check first with your insurance company to make sure you are covered against floor collapse, leakage, or other water bed perils.


there is also the weight of the individual adding to the figures. Figuring an average weight of 250lb & 6ft tall, it is placing roughly 40 more lb per sqft laying down & if they sit on the edge of the bed, probably double that in that particular spot. Though, I disagree about average bedrooms only being able to withstand 40 lb per sqft. If that was the case, people would be falling through their floor everytime they walk.


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## ront02769 (Nov 28, 2008)

talukdar said:


> I think waterbed in second floor with weight around 2631 lb is not a good idea, rather you can install the waterbed in ground floor, it will be better for you.
> This 2631 lb all time put pressure on your roof, that's why rooftop may collapse, so be wise and carefully make decision.


How will that waterbed on the second floor cause the roof to collapse? Ron


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## ront02769 (Nov 28, 2008)

Hick said:


> there is also the weight of the individual adding to the figures. Figuring an average weight of 250lb & 6ft tall, it is placing roughly 40 more lb per sqft laying down & if they sit on the edge of the bed, probably double that in that particular spot. Though, I disagree about average bedrooms only being able to withstand 40 lb per sqft. If that was the case, people would be falling through their floor everytime they walk.


Curious as to how say two 250 pound people (500 lbs total) are adding an extra 40 lbs/square foot?

Also, most of you all are missing the important factor of load distribution. Think about it. Most residential floors other than bedrooms are designed for 40 psf load. So employing the logic that most are using, if you take your hypothetical 200 lb man and figure that if he stands with his feet together he is covering say 2 sq feet, he would end up in the basement as that would be 125 lbs/ sq ft! So why can I walk around my house? Partly because the overall floor system distributes the load. Ron


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## Daniel Holzman (Mar 10, 2009)

There are a few things to understand about floor loading versus floor capacity. Typical building code specifies a distributed live load on floors, often 30 psf for bedrooms, 40 psf for living room, with possibly different live load for other types of space (attic, deck, garage etc.). The live load is added to the dead load, often taken as between 5 and 10 psf, to arrive at a total load of around 40 psf for a bedroom. Local code may vary.

The total distributed load is then used by the designer of the house to size the joists. This is done by assuming that each joist carries a tributary area equal to the spacing between the joists multiplied by the effective span of the joist. So a 10 foot long joist spaced 16 inches on center has a tributary area of about 13 square feet. Multiply by the code required dead load of say 40 psf, you get joist loading of approximately 520 lbs on the joist.

As to the question of why a 250 lb man standing on a joist does not cause the joist to fail, that is because the man is a point load, not a distributed load. If he is at the center of the joist, he exerts a point load of 250 lbs on the joist. Comparing point loads to distributed loads is a little tricky, but in this case the point load at the center is no more severe than the design distributed load, and the joist is OK. If you had a line of 250 lb men each taking up 1 square foot along the joist, you could in theory get 10 men on the joist, for a total load of 2500 lbs. A joist designed for 520 lbs would fail, and the men would fall through.

There are a couple of details here that complicate matters. First off, joists are almost always covered with some type of sheathing, typically plywood. The plywood adds some strength to each joist. Second, joists are typically blocked to the next joist, which adds some strength to each joists. Third, there is a built in safety factor in the code, so although you design for 40 psf, typically you could put 80 psf or so on temporarily without failure. You would not want to put that load on long term, but in a short term pinch you could do it.

So for the waterbed, there are a few things to consider. First off, the waterbed is a long term load, so you do not want to be using the short term safety factor. Second, the waterbed is something like five feet wide, so it would likely cover four or five joists. As to the load, the waterbed is a distributed load, but only over a portion of the joist, so it needs to be analyzed as a rectangular load over part of each joist that it covers. You add that load to the remaining distributed load in the room to get the total load on the joist, which you then use to see if the joists are strong enough.

Or you just put the bed in, fill it, and hope for the best. P.S. when I was in college, I had a king size waterbed, which I dragged from apartment to apartment. It never fell through, but it did leak one day, and caused damage to the room below. But that was in the good old days of college, I have not had one since. Best of luck with the project.


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## ront02769 (Nov 28, 2008)

Daniel, that is what the liner that should have come with your waterbed if for!! But assume that I put my buck eighty on my bedroom floor on the advantek BETWEEN two joists. While I am loading a point, isn't the floor system spreading that out between the joists on each side? Ron


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## Hick (Nov 21, 2014)

take a 250lb man, have him stand on 1 foot, on his toes. Your covering roughly 2-3 square inches then. Roughly 80 pounds per square inch then. Lets not even stand on the joist, but on the flooring directly center between the joists.

I have yet to see people fall through the floor except in trailer houses & mostly because those are poorly built as it is.


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