# Calculating proper weight for bookcase on 2nd floor



## Gary in WA (Mar 11, 2009)

_____________________ Welcome to the forums!_________

Check the bottom of case to see if full bearing or just at ends. Measure between walls directly below location for span to bearing. Measure joist height at stairs from floor to ceiling below- for joist depth. Use a stud finder (unobtrusive) or a thin nail driven through ceiling drywall after locating joist by sounding with fist- to find the on center spacing of floor joists. If bearing wall below, good to go. Find your span in tables to get an idea of where you stand, choose State, Code, floors; http://premiumaccess.iccsafe.org/

Or we can look up your total load rating if you know the species, grade, and rating of the joists.

Gary


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## JonConklin (Jul 17, 2016)

Hi Gary,

Thanks for your reply.

The builder sadly went out of business so I don't think I will be able to get information from them.

However, the room is above the garage so I can take some pictures which may be useful. Everything underneath seems to be covered with drywall in the garage, but I do see some supports (Namely some going down wards and then another spanning across - looks like some sort of large support beam).

The room and where I intend to put the book cases (haven't bought them just yet, but I most certainly want it to be full bearing - not just 4 points at the corners. At the very least, I want the 4 edges to continuously touch the floor) are against outside walls.

I will do a bit more research and provide some pictures and anything additional I can find. I will also try to get a stud finder to get some measurements for that.

Finally, the website doesn't seem to have codes for my state - NC (unless it is under the more generic ones?). The house was also built in 2001.

Thanks!


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## ront02769 (Nov 28, 2008)

Without getting into detail, ciphering things out your way isn't how psf live load works. If it WERE the right way to do it......and my floor was rated 40 psf......and I stood on it with my feet both together......I would immediately end up in the basement since I would be occupying about one square foot and exerting 180 lbs downward force. For me, a bookcase that size against a wall would not be a worry. Ron


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## JonConklin (Jul 17, 2016)

ront02769 said:


> Without getting into detail, ciphering things out your way isn't how psf live load works. If it WERE the right way to do it......and my floor was rated 40 psf......and I stood on it with my feet both together......I would immediately end up in the basement since I would be occupying about one square foot and exerting 180 lbs downward force. For me, a bookcase that size against a wall would not be a worry. Ron


Of course...houses should be falling apart left and right 

I just rather have a better understanding and idea of the reality of the situation and future. We both know my current way is flawed (which is why I originally started this thread).

Thanks for your reply.


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## ZZZZZ (Oct 1, 2014)

Think of the load your refrigerator puts on the floor.

Bookcase and books, no problemo.


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## woodworkbykirk (Sep 25, 2011)

a frig isnt exactly much of a comparison to 1000 lbs... a whirlpool tub is all the water and the weight of a person is


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## JonConklin (Jul 17, 2016)

HI,

Took some pictures of the garage ceiling (underneath the room). The room is directly above this corner and spans roughl ~12 feet in each direction. I do not know if this is helpful, probably not since it is covered with dry wall.

http://imgur.com/a/QqU8b

Ty.


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## SPS-1 (Oct 21, 2008)

Jon:
The sketch below is very unlikely to be correct, but best I can come up with from your description. Wall that runs 12 o'clock-6 o'clock looks like an exterior wall in the photo, but you write that room above extends 12' in all directions. Can you please make a sketch like this that shows the garage walls and beam (because that defines where the joists are) and where the bookshelf is ? Best if you can mark if each wall is interior or exterior.


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## JonConklin (Jul 17, 2016)

Hi SP-1,

LOL whoops! I did a bad job describing the room. I meant the room extends ~12 feet long the 2 walls seen (the 'left' with the garage door, and the 'right' with the window).

Modified your sketch in MS Paint to hopefully be more clear. Your bookcase placement is perfect - that is the wall I will be intending in placing the book case. Both garage walls in the image are exterior. Top garage wall has the garage door (1 large door that can fit two cars).

Many thanks.


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## SPS-1 (Oct 21, 2008)

I would expect you have a good situation there. The joists will be running perpendicular to the beam, which means you are distributing the load over several joists. And the support for the joist will be right behind the bookcase.


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## JonConklin (Jul 17, 2016)

Great! Thanks a lot.

I'll load that wall up then with my books!

Looking at your image and the joist placement, it makes sense that is how it would be set up - since garages are pretty big, there would need to be a support beam in place and the joists would run perpendicular there.

I want to thank everyone who replied to this thread and helped me out in a respectful manner. I know online forums can be pretty toxic, but everyone has been very nice here. You have my gratitude.


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## Tom738 (Jun 1, 2010)

The only situation where I would worry about it is if there's a spot in the house that's especially weak structurally. I have been careful about bookshelf placement over the framing around a missing chimney, for example, and would be careful about it in an old house or one with really substandard building. But generally (so long as you're not truly creating a library) the additional load from a bookshelf or two, especially if distributed across multiple joists right next to a supporting wall, isn't a problem. If it's set up like that, I wouldn't worry about it.

On the other hand, I have known people who have had extra supports added in their basement when they install a heavy refrigerator. But those people tend to be either rich or especially risk-averse, or to have installers who want to be rich or are especially risk averse.

Disclaimer: not an engineer. If you want to be 100% safe, open up the wall and do the math or hire an expert to do it for you. I wouldn't bother unless I saw a red flag.


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## ront02769 (Nov 28, 2008)

To the OP, here is a decent article explaining psf floor loads.....even though it is with regard to placement of aquariums it is written by a structural engineer who seems to have a good sense for explaining things in a way that is easily understood. Enjoy. Ron

http://www.african-cichlid.com/Structure.htm

And as an aside, there is an amazing pix or cichlids at mystic aquarium!


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## JonConklin (Jul 17, 2016)

Tom738 said:


> The only situation where I would worry about it is if there's a spot in the house that's especially weak structurally. I have been careful about bookshelf placement over the framing around a missing chimney, for example, and would be careful about it in an old house or one with really substandard building. But generally (so long as you're not truly creating a library) the additional load from a bookshelf or two, especially if distributed across multiple joists right next to a supporting wall, isn't a problem. If it's set up like that, I wouldn't worry about it.
> 
> On the other hand, I have known people who have had extra supports added in their basement when they install a heavy refrigerator. But those people tend to be either rich or especially risk-averse, or to have installers who want to be rich or are especially risk averse.
> 
> Disclaimer: not an engineer. If you want to be 100% safe, open up the wall and do the math or hire an expert to do it for you. I wouldn't bother unless I saw a red flag.


Thanks for the information. I have no way in telling if there is some structural issue. However, the previous owners had what looked to be a rather large sized wooden kids bed in the same location where I'll be putting these bookcases. I am hoping it is OK. I also have been considering seeing if I can add some extra supports somehow. It has been quite difficult in finding a book case that meets my requirements that does not weight +300 lbs by itself!!


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## JonConklin (Jul 17, 2016)

ront02769 said:


> To the OP, here is a decent article explaining psf floor loads.....even though it is with regard to placement of aquariums it is written by a structural engineer who seems to have a good sense for explaining things in a way that is easily understood. Enjoy. Ron
> 
> http://www.african-cichlid.com/Structure.htm
> 
> And as an aside, there is an amazing pix or cichlids at mystic aquarium!


Thank you. I have just read this and will read this again!


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