Wall unit bookshelf Shelving question - Warping walnut ???

  • Advertise with us

« back to Wood & Lumber forum

Forum topic by lepelerin posted 04-23-2013 01:12 AM 2844 views 0 times favorited 4 replies Add to Favorites Watch
View lepelerin's profile


495 posts in 2530 days

04-23-2013 01:12 AM

Topic tags/keywords: question walnut bookshelf

Question about shelving,

hi all,

Here is the situation. I have been asked by a friend to build his wall bookshelf. It will be installed in a recessed wall. The bookshelf will be 12’ long (3.5 m), 8’ (2.44) high and 9” (23 cm) deep. I will make it into 3 pieces. For ease of explanation I will call them left, right and middle section. The left and right sections are 4’3” (1.3 m) wide and the middle section is 3’ (90 cm) wide. All of them 9” deep.

The frame (sides, top and bottom) will be made of solid walnut, 1” thick. There will be a total of 6 to 8 shelves in each section. Each section will have 2 or 3 fixed shelves and the rest will be floating shelves, I mean resting on a pin similar to that,43648,43649

Each shelf will be approximately 3’ to 4’ long by 8” wide, 3/4” – 1” thick

Here are my questions:

1) I cannot find walnut as wide as 9” wide. I will glue pieces together to get the required width.
Should I just glue them or use dowel to reinforce them. There will be a lot of weight and stress on everything.

2) At the store they told me that the floating shelves will be warping over time? What do you think? They recommended walnut-baltic plywood. The issue that I have with plywood is that my shop is in the basement, very unpractical next to impossible to cut a 8×4 sheet and the store does not cut plywood. Using plywood would require edging too. It might be more stable over time but my question is walnut prone to warp a lot? I have no experience with walnut. I do have a bookshelf build in pine with floating shelves (1’ wide, 55” long, ¾ thick) and they seem to be stable over time. I had this bookshelf for over 10 years the are still flat.

So the questions is should I use solid walnut or not? Would you use solid walnut for floating shelving to built your own library?

3) This is relative to how to anchor the unit to the wall. I was thinking to anchor (with what is to be determined) the left side of the left unit and the right side of the right unit to the recessed wall. The middle unit would be attached to the adjacent side from the left and right unit. Would it be ok?

Those are my main questions at the moment, but I am confident if this project goes ahead (and so far it seems it will) I will then have more questions.

I hope you will be able to help answer my questions. In advance thank you for your input, advice, comments and whatever I did not think of.


PS: If this topic is more appropriate in another forum please let me know.

4 replies so far

View Marcus's profile


1163 posts in 2225 days

#1 posted 04-23-2013 10:44 AM

1. I use biscuits when edge joining wood, but I do not believe they provide much if any strength and I have never had any issues with my joints separating. You may want to consider dowels to help you align the pieces though.

2. I would personally use plywood or design some sort of support for the middle of the shelves. The length you’re talking about is a pretty good stretch for 3/4 stock. Plywood would be more stable than solid wood, avoid the issues you worry about in number one, and save you a few bucks. Also, is the shelves are going to be stacked with books, you won’t see it anyways.

As for transporting and storage, I’m in a similar boat. Most stores who sell nicer plywood will cut it, you may want to look around a bit. In a pinch I’ve ordered from Home Depot online and had it delivered. Their stuff isn’t too bad and very convenient.

3. I would attach the middle shelf to the wall.

View Nomad62's profile


726 posts in 3163 days

#2 posted 04-23-2013 05:03 PM

I would recommend biscuits as well, they are thinner but allow for more glue contact due to their width. Making up a few out of your walnut would be best. My experience with plywood is that it will bend easier than solid wood but it will hold an original shape better if bent. Solid wood will be much stronger, and if it ends up a full 1” it should be good; but, as Marcus stated, plywood is more stable. Could you cut the pieces of plywood outside first, then take the pieces inside to build? Keep in mind that books get awfully heavy, common sense prevails. If it were mine, I’d go with the wood. Lastly, your mounting system seems like a good idea, tho I might suggest a moveable support for the center section to allow for wiggle and/or expansion or contraction issues; mounting to the wall may be better.

-- Power tools put us ahead of the monkeys

View JCantin's profile


179 posts in 3617 days

#3 posted 04-23-2013 05:38 PM

You will get a big assist by adding a front lip or edging of solid material to each shelf. This will stiffen the entire shelf and reduce sag. There is a calculator out there for determining sag given the span. FWW reports that the eye can detect as little as 1/32” of sag per foot. With the calculator you can see how much sag is reduced by the addition of the edging.

View lepelerin's profile


495 posts in 2530 days

#4 posted 04-24-2013 05:20 PM

Thank you to all for your suggestions.
As of now the bookshelf is put on the back burner. My friend had an unexpected event happened in his condo. Some of the ceiling collapsed after the painter worked on it, so no more money for the walnut bookshelf at this point.
Again I will keep your advice when it’s time to build it.
Thank you

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics