Shelving Unit Questions

Stuart Ablett

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OK, next project for a client, yeah, that one, but they really need this, and I'm working up a quote, all fun being in business for one's self right...? :rolleyes:


OK, here is a picture of the space.......


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Along that wall, not up to the ceiling, but only at the 182Cm mark (just about 6') there is a conduit that comes out of the wall and goes to the light on the ceiling, you can see it in the center of the picture, there is a round junction box on the wall behind the pink plastic tray at the top of the shelf. This limits the height to the 182Cm/6' mark, which is just fine.


See all the boxes with the "Z" on them, that is what is going on the new shelving unit.


The table on the left side, near the window is leaving the room, so I'll be making three units. The space is 241Cm wide or just about 95 inches, so each unit will be about 80 cm wide (31-1/2"). The units will be 45cm deep, almost 18". They need to carry a lot of weight, those boxes are basically a solid piece of paper, printed material.


Here is what I'm thinking, I'll make each unit with a solid immovable shelf in the middle to make the units stronger, and then two adjustable shelved in the top area and two in the bottom area.


I will be using a type of plywood that is lumber-core that has a plastic coating on it, melamine I guess they call it. The stuff is not cheap, but boy it sure makes the finishing easy! I have the choice of either 18mm (23/32") or 21 mm (13/16") plywood. I'm thinking the thicker stuff might be the better option, but even so, do you think I need a center piece that will go top to bottom?


Two of the units will have door full doors on them, euro hinges and just thinner melamine coated plywood, nothing fancy, just clean lines. the third unit near the window, will be too close to the table/desk to have doors that open out, I'm thinking maybe to put sliding doors on that one.


My biggest question is do you think the span of 31-1/2" will need that center support?


I admit it would be extra strong and it would give the doors something to close against too.


What say you?


Cheers!
 
I'd weigh one of the boxes and then figure out an optimum stacking to see how much actual weight each shelf would be holding, that would also help to make sure the middle fixed shelf was positioned to permit optimum use of the adjustable shelves. Then run the load through the sagulator to get an idea of what might happen. If it's going to sag you could always reinforce the shelves with a hardwood edge or even aluminum angle inlet into the edge for extra stiffness.
http://www.woodbin.com/calcs/sagulator.htm
 
OK, next project for a client, yeah, that one, but they really need this, and I'm working up a quote, all fun being in business for one's self right...? :rolleyes:
As long as they ain't taking your design and then shopping it out to someone else. That used to burn me to no end (and my design plans got a whole lot vaguer) - this was mostly with network/computer stuff but a similar problem I suspect.


My biggest question is do you think the span of 31-1/2" will need that center support?

I admit it would be extra strong and it would give the doors something to close against too.

Need it? I don't think you would need need it. But I would probably still add it. Generally i try to err on the side of overbuilding and dang paper is HEAVY :D The lumber core will be nice as well, I haven't seen that locally with melamine coating (just mdf).
 
here's my input. go with the thicker plywood. i have a book case (glass doors with no center support, about 4 ft wide, a little over a foot deep, with no center supports), see pic below. 10 years now, and no sagging, with about 30 lbs of book on each shelf. as for what to charge, i would go with roughly $300 (30.6k yen) per unit, above the cost of materials for your time.
 

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I think if you use a solid piece of hardwood attached to front of ply and at back, you would give it enough strength to prevent a sag an inch, inch and an 1/8th glued to front and back, no sag.just read teds post,, agree with him
 
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I assume this is fastened to the wall somehow. With a tall heavy load like this tipping might be a problem.

To see if a center support is needed, I would mock up one shelf of the desired length between a couple of sawhorses and stck the anticipated paper load on it.

If it sags even a little, like 1/4 inch, it will probably get worse over time, with use. In which case I'd simply put the center support in down to the floor. Like a load bearing beam in a house.

If you want to cheap out on materials, (or go for an open look) and it is fastened t the wall, you might be able to get away with a small peice of material fastened to the wall in the back of each shelf, and a 2" wide support down the front.

Good luck.
 
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