My next project is building an in the wall 3 shelf bookcase to accommodate my printer, my modem and router, and hopefully an aquarium. I want to use 3/4" birch veneer plywood with dados for the unit including the shelves. The aquarium will weigh 175-180lbs when loaded. The shelves will be 27.5 " wide because the unit is going in an area that was built around a stove pipe and the studs are 27.5 " apart. Will this shelf support the weight ? If I added a stud inside each of the existing studs to bring the width down to 24.5", would this support the weight if the 27.5" span will not work?

  • I do hope you are planning on putting the aquarium to the bottom, right? Keep the water below the electrical stuff and all that.
    Jul 21, 2015 at 16:57

2 Answers 2


Using the Sagulator, you're borderline for a noticeable sag... It will also depend on how deep your shelves are, and how wide the aquarium is (I assumed 16 inches deep shelves). Since you're using plywood you're going to be facing the shelves with something, right? I would just double up that shelf (two layers of plywood glued together) and you should be fine.

Also, you can run a strip of the plywood along the bottom back edge of the shelf which, combined with the front facing, should support all the weight you can throw at it.

  • If the Sagulator says it will sag a bit then you don't put a 200 lb aquarium on it. This is much much different than having 200 lb worth of books.
    – DMoore
    Dec 18, 2015 at 23:15
  • @DMoore Well, that's why I said he should double the shelf and add facing on the front and back. Thanks for the comment though.
    – DrewJordan
    Dec 18, 2015 at 23:41

No, it will not support the weight. It will bend in the middle. You need to either put some studs underneath where most of the weight will be. Generally, studs are 16" on center. Or, you can double up the studs which will work also.

Hope this helps.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.