# Shelf Strength



## Tig1242 (Mar 16, 2012)

I am looking at building a bookshelf 3' wide. I am concerned about shelf sag, so what would be the strongest wood, ply wood, MDF or something else?

Do I need to put in a center support column so the shelves would be only 1.5" on each side?

Thanks


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## Charlie5791 (Feb 21, 2012)

The Sagulator is your friend!

I used 3/4 inch, 11-ply birch plywood for the wide shelves in our kitchen cabinets. They all got "faced" with 3/4×3/4 maple. That facing was more for looks as I don't have edge banding, but the hard maple will add even more sag resistance. The 3/4 plywood by itself has real good numbers though.


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## tenontim (Feb 24, 2008)

For 3' shelves, 3/4" lumber or plywood will be strong enough, especially a hardwood like oak, maple, ash, etc. If your bookcase is going to have a back, you can cut a dado into the back or put screws through it, into the shelves to give extra support to the shelves,


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## Tig1242 (Mar 16, 2012)

Thanks Guys!


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## renners (Apr 9, 2010)

Tenontim is right, attach the shelves to the back with screws to eliminate any chance of sagging


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## Charlie5791 (Feb 21, 2012)

I have adjustable shelves. Kinda hard to screw them in from the back when the cabinet is screwed to the wall. 
Sagulator is an awesome tool… hehehe


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## AndyDuframe (Jul 27, 2008)

I've always liked the method of attaching a hardwood band or apron across the front of the bookshelf. This makes it almost impossible for the shelf to sag. Plus, this is just about the only way to add support to an adjustable shelf.


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## MonteCristo (May 29, 2012)

Personally I would put a center support on a 3ft span. Maybe stiffening the back side of the shelf as described will do but why risk it, especially if the shelf will store a bunch of hardback coffee table type books that are really heavy.


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## LeeBarker (Aug 6, 2010)

I agree that 36" is a mighty long span.

You could edge your shelves with 3/4×1 1/2 or 1 1/4 stock, front and back, and they'd be great, but you're adding some look of mass there that would have to blend right with the carcase.

Kindly,

Lee


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## alba (Jul 31, 2010)

Just put a lip on it

So it looks like a capital L

Larger the lip the larger the span that

is possible

jamie


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## Charlie5791 (Feb 21, 2012)

3/4 inch shelf faced with 5/8×1-1/4 walnut. This is for a 33 inch shelf that will hold a microwave on one shelf and cookbooks on the top shelf…


















I haven't put a finish on this piece yet. It does add some mass, but this hutch will sit on top of an inch and a quarter walnut counter top so it should look fine.


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