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Think it'll hold?

915 Views 14 Replies 11 Participants Last post by CaptainMick, May 3, 2022

CaptainMick

Discussion Starter · Apr 30, 2022 (Edited by Moderator)

4

My wife wanted room for all her books and we decided the walls above her records in the spare room would be the place. I couldn't afford the crazy prices for wood at this time, so gathered scraps from a local cabinet shop and glued up 10" deep panels in 24" lengths. They are about 3/4" thick. Then I dadoed the dividers and glued it all up. For the back, I screwed 1/2" pine plywood (again, free from the scrap yard at cabinet shop) onto the back of the shelves. I used about 40 #8 screws of 1 1/2" length to screw the plywood on. It is also titebond glued and 18ga Brad nailed.
When I installed them onto the wall, I used 12 large 4" Timberlock lags to screw the plywood backing into the wall, which is solid log wood.
We just got done putting books onto them and I started getting nervous… think it'll hold? I'm wondering if the backing would come out of the shelves? Internet says with "the average weight of books per foot" that each shelf holds a total of 500 pounds. If you don't think it would hold, what would you do to support it?
Thanks!

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Novamr99

· #2 · Apr 30, 2022

If it would make you sleep better, I'd suggest putting a cleat along the bottom to support the "down pressure" then put large flat washers on the lag bolts (one at a time)to keep the heads from pulling through.
The shelves look plenty strong to hold the books.

Good Night. Zzzzzzzzzz….

CaptainKlutz

· #3 · Apr 30, 2022 (Edited by Moderator)

+1 Add a cleat.

Put a 1.5×2 cleat, along the bottom of the vertical dividing panels to add support of downward pressure of dado'd grid. Use #12 wood screw or GRX fasteners that penetrate ~1.25-1.5" into the studs (add length to pass though the drywall and cleat).

Cheers!

LeeRoyMan

· #4 · Apr 30, 2022 (Edited by Moderator)

Is your back 1 piece or 4 separate pieces each sharing an upright?
1 piece and I'm sure you are good
Separate pieces? then it depends on how good you attached each back to each half the upright.
As for now, you're good until your not good….

Your back is not going to fall off the wall so much as the cabinet portion detaching from the back(s)
(Adding a cleat underneath isn't going to do anymore than the plywood already anchored to the wall.)

CaptainMick

Discussion Starter · #5 · Apr 30, 2022

The back is actually two pieces, each are 96" long and 13" wide. Each piece of plywood has 6 timberlock screws into the wall.
That's my thought too… I'm not worried about the whole thing falling off the wall. I'm worried about the shelves coming apart from the plywood backing, which was put on with 40 screws, glue and some brad nails.
Just worried it's gonna come crashing down in the middle of the night

pottz

· #6 · Apr 30, 2022

dont worry about it,ive seen worse-lol !

MadMark

· #7 · Apr 30, 2022

If it starts to creak …

tomsteve

· #8 · May 1, 2022

if you have a back on it and all of the pieces are screwed and glued to the back, id say youre fine.

word of advise on next build: screws dont hold the best screwing into the edge of plywood. i prefer pockethole screws into the face- screwing through the plies.

ManySplinters

· #9 · May 1, 2022

2

The books would hide some additional glue blocks… help tie the shelves to the back.

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CaptainMick

Discussion Starter · #10 · May 1, 2022

I do like that idea cause you wouldn't be able to see it. Could screw through the glue blocks into the wall for additional support as well.
Update: it didn't fall down last night.

Foghorn

· #11 · May 1, 2022

Looks good to me but I wouldn't put a rack of wine glasses on the bottom just in case.

CaptainMick

Discussion Starter · #12 · May 1, 2022

It's even worse then that… my vinyl records are below it!

Jerroni

· #13 · May 1, 2022

If it were me, I'd just take off the top row of books - you can use the top shelf for lighter items. You've load-tested, but who knows how close you are to the failure point?

Overall, it seems like a solid build. I would have gone for the cleat, too - but the glue-and-screw method, the solid log wood construction for the wall, and the 1/2 plywood backing + lag screws should work. It's just that uncertainty (and Murphy's law) makes it not worth it. If it does happen, a failure is likely to be sudden, due to the stiffness (glue + screw).

Removing at least some of the books is an easy fix (adds more of a factor of safety). When books are out of reach (like they are now) - who's going to read them? If there is protest, maybe you can cut down half of the books on the top shelf. Still a big change in load.

Tony1212

· #14 · May 2, 2022

So I'm looking at this (edited for MY clarity):

- For the back, I screwed 1/2" pine plywood onto the back of the shelves.
- I used about 40 #8 screws of 1 1/2" length to screw the plywood on.
- It is also titebond glued and 18ga Brad nailed.
- I used 12 large 4" Timberlock lags to screw the plywood backing into the wall, which is solid log wood.

- CaptainMick

With the 5 uprights spaced only about 1 to 1.5 feet apart, I wouldn't be concerned with the 3/4" horizontal shelves buckling.

My biggest concern would be the shearing force for either the screws holding the assembly to the wall or the shearing force of the fasteners holding the back plywood to the shelves.

12 Timberlock lags into solid wood should be more than sufficient to hold that. Some contractors would use less than that for a whole backyard deck.

Fastening a board to the back of the shelves is less than ideal. I would have made the shelves a 1/2" narrower and had the perimeter boards (the carcass) surround the back panel (i.e. the back panel would be inside the carcass so you couldn't see the edges of the back panel from the side, top or bottom). But with all of the glue, nails, and screws, you should be good.

With the back panel inside the carcass, the top shelf acts a structural cross member that helps distribute the weight to the back panel which puts the weight solely on the lags holding it to the wall. Your way put the entirety of the weight on the glue, nails and screws before it can transfer that weight to the lags. It's a subtle difference, but in your case, I'd sleep easy.

If I were to reinforce it, I'd get some fancy shelf brackets and add them underneath the two outer uprights and the middle upright. I doesn't look like they'd be interfering with anything.

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CaptainMick

Discussion Starter · #15 · May 3, 2022

Thanks for all the suggestions. I kept waiting for them to fall so decided I better do something just so I could relax. So this is what I did…

1). I placed a 1 1/4" by 2" cleat under the entire bookshelves making sure it supported the dividers as well as the backing

2) I used ManySplinters suggestion and put a 1 1/4" triangular piece on top of the upper shelf behind the books. It got glued and screwed in with 3" construction screws as did the cleat.

Now, at least, I feel like I did something. May need to start another project just so I can stop thinking about it.
Thanks again for your suggestions.

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