I am building a large bookcase, 12 feet wide by 5 feet high. Not a problem if it sits on the floor but the twist is that I must raise it up 18" due to a wall to wall hot water baseboard heater and electrical outlets along that wall.

I plan to use use 9 heavy-duty angle supports (rated 125 lb load) every 16 inches on the wall and wood support legs (1 inch decorative spindles every 3 feet on the front edge of the 12" depth unit. I estimate the load to be close to 800 lbs of books and items plus the lumber.

I have a few questions:

  1. I believe I have sufficient load support. The brackets alone support 1,125 (9*125) lbs. With the additional front leg support, does this provide ample support?

  2. What kind of screws should I use to hold the brackets? The sheetrock is 5/8 thick and the support bracket is 1/8". I don't want the screws supporting the brackets to snap under the load. Would 3" steel nails be better?

  3. The leg supports are 1" spindles. Would it be advisable to use a 4X4 baluster - the kind used at the end of a staircase. Obviously a 4*4 would provide a ton more support - but its bulkier and less attractive -- but is it overkill? I guess I can space them every 4 feet?

Thanks for any assistance!

PS - The unit would be secured at the top. It will reside in a space that has a soffit for ductwork and will be secured to the crossbeam for stability, so no danger in tipping forward.

1 Answer 1

  1. The angle brackets alone should be adequate if two things are true: Your case is well-built, and it's fastened securely to the wall. The spindles will do little to support the unit should they be accidentally knocked out by children, pets, or you. They shouldn't be considered a critical support component, in my opinion.

  2. No, don't use nails. They don't have the pullout strength of screws and aren't removable (practically speaking). Use large wood screws (#14 or so), or lag screws (1/4" to 5/16" or so if the bracket holes allow). The key is penetration into the framing lumber. I'd want 2" of depth into the lumber itself. Pilot properly for maximum strength (slightly smaller than the screw shank). Also a factor is the number of screws per bracket. I'd want at least two. Also a factor is mounting of the cabinet to the wall. If you have a stout back panel, or a set of rails through which you can fasten, decorative or hidden screws into the framing will take much of the load off the brackets.

  3. I addressed this earlier. Any support legs must have adequate diagonal bracing to prevent knockout. This means that the effort and expense may make them impractical. In any case, 1" is probably too small. Look to heavier oak stair balusters in the 1-1/2" or 2" size, with the milled dimensions being slightly smaller.

  • Excellent information and great idea with the back panel / rail. I'll fasten 1x4 rails and screw them to the framing. I believe the unit is sturdy. The outside frame is double 3/4" boards and those are secured to sidewalls, so there is no left to right horizontal movement. The vertical sections are secured from the top and bottom with two 2" screws at each joint. The 2 middle sections will carry a heavy load (encyclopedia books) so I made 3 shelves in each stationary with 2 3" screws from the side. The other 3 sections contain 5 adjustable each. The brackets have 3 holes so I am good.
    – John Jacob
    Nov 21, 2016 at 6:20
  • I have come across some black wrought iron angle brackets. They are 'decorative' in appearance but appear even sturdier than the ones I purchased -- but the web-site does not list the load. I plan on calling their customer service tomorrow and hope they know. The cost is $38 each but if it provides extra support, its worth it for the peace of mind. That will also eliminate the need for the extra balusters and its diagonal bracing.
    – John Jacob
    Nov 21, 2016 at 6:20
  • Considering that the weight is carried almost entirely in shear against the wall, the rated load of the brackets is somewhat irrelevant. Most important is the fastening to the wall. I wouldn't bother calling the company. Use them if you like the look, otherwise use simple, heavy duty brackets in hidden locations.
    – isherwood
    Nov 21, 2016 at 14:27

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