Replies

1. 
   BG | Aug 27, 2002 01:26pm | #1

   bg,

   Attaching to the ledger strip should be fine, of course, three feet wide is big..how are you supporting all that weight?

   In the latest issue of FWW they have a bookcase that is very interesting.  Relative to your issue, the base is flat for a coupla inches and then is cut at a 5 egree angle...causing the weight of the bookcase to pitch backwards naturally.  I think that design would work around any issues with the carpeting. good luck..BG 

1. 
   beeg | Aug 28, 2002 08:04am | #2

   thanks.  Plan was to solidly attach the back and screw through back into studs with much of weight on ledger strip.  Was curious to see if anyone thought a base was needed under the units as well, hence the carpet question.

   bg

1. 
   DavidxDoud | Aug 28, 2002 08:24am | #3

   if you're going to actually store books on the shelves (heavy),  I'd not set the shelves on carpet/pad,  screw to the wall,  and then load - I suppose if there were a cleat on each shelf screwed to the studs you would probably get by with it, - wouldn't be hard to set shelf unit in place and cut carpet/pad with a sharp utility knife to fit base - or maybe set the unit in place, load it,  wait a week and screw to studs -

2. 
   BG | Aug 28, 2002 01:02pm | #4

   bg,

   I actually missed your question, sorry.  I would not give up the base support of the floor, as David indicated, this thing is gonna be heavy.  I made a 6'x26" bookcase for the family room which is carpeted also and with baseboard heating (hot water system).  I made a supplemental base to fit around the baseboard heating so the actual bookcase could fit snuggly against the wall where it was attached to studs. Its height now is close to 7 feet with the base.  Cutting the carpet was not an option and has not been an issue

2. 
   DavidxDoud | Aug 28, 2002 04:19pm | #5

   actually,  I missed the question also - hanging 6' tall units that would store books or similar heavy items is not something to approach lightly (almost a joke there) - my gut feeling is that standard 2X4 framing would be mariginal and the risk of catastrophic failure too high not to take the shelves to the floor - my original misreading thought that you might build 6' high units,  set them on cushy carpet,  and blow a couple of drywall screws into the studs,  load them and have them settle an inch,  with associated problems - I suppose there is a way to hang units such as you contemplate,  perhaps someone else will jump in here - I know I would be extremely cautious - I serve on the local library board and a full 3' X 6' stack is a dangerously heavy unit - be careful -

1. 
   billballeza | Aug 29, 2002 05:42am | #6

   Now you guys have me worried. In my garage I built a hanging shelf unit to store lumber. I have two seven foot runs of 2X4's spaced six feet apart. They are attached to the ceiling joists with three inch drywall screws along the entire run. Attached to the 2X4's are four 24" 2X4's on both sides.. and then a 2X4 frame attached to those as the weight bearing base or "shelf". I plan to store the equivalent weight of six sheets of 3/4" plywood on this unit. Am I fooling myself?

   bill

1. 
   DavidxDoud | Aug 29, 2002 07:53am | #7

   let me preface this with the disclaimer:  I am not an engineer - (and about to prove it)

   what's a half dozen sheets of 3/4 ply weigh? 3-400 pounds,  maybe?

   attached to the ceiling joists

   what kind of ceiling joists? the cheapest possible truss or 2X12s or something in between?

   assuming the joists are up to it,  it would appear to me the weakest point would be where the 24" 2X4s are attached to the 2X4 attached to the joists - where the integrety of the assembly depends on the shear capacity of the screws(?)  so you have maybe 8 screws per side bearing the weight - I would guess that the weight would be uniformly spread across the assembly,  so 400 pounds divided by 16 screws = about 25 pounds of shear on each screw - my experience suggests to me that 3" screws are up to the job - that accounts for the static load - loading and unloading will apply transient loads as the ply is shoved and maneuvered and depending on access and technique could apply force to the first 'shelf' assembly of several times the static load which my experience suggests might approach a critical limit at the weak point - so... I'd think about strapping the the shelf assembly together to provide peace of mind - and also pad the lower corners so you don't bust your head on it,  probably the biggest danger -

   I look forward to others opinion on whether my analysis is reasonable -

2. 
   BG | Aug 29, 2002 12:27pm | #8

   Bill,

   I would agree with everything David said (also a non-engineer opinion) except maybe that 6 sheets of 3/4 ply weighs 300-400 pounds.  Every time I have to horse those sheets around they feel like 300 pounds each..lol. Of course that is assuming you have 2x10 at a minimun and not 2x4 trusses.

   Regardless, do you really want to store plywood up that high?  Trying to get sufficient leverage so your finger tips can pull out a sheet ...it'll do a job on your manicure...lol

   I store light stuff overhead (moldings,sawdust, empty tool boxes).  I ran a one inch dowel between to hanging 2x4" about 12" hanging off of 2x12".  I bolted the 2x4 to the 2x12.  Good luck 

1. 
   billballeza | Aug 30, 2002 12:18am | #9

   David and BG.. thanks for your opinions, assessment and advice regarding my storage shelf. I particularly like David's approach at figuring the weight distribution or "shear" by the number of screws. Strapping the 2X4 runs to the 2X6 joists would have been my first choice but the previous owner sheetrocked the entire garage, which makes it look nice but also makes it tough to work with the structure. I may take your advice, BG and run lag bolts through the assembly. I just bought an 18v DeWalt driver/drill which should handle that job. (I blew the clutch on my lower voltage Makita just driving all those 3" drywall screws.) All I have up there right now is my 8'ladder and the scrap left over from this project and my Norm Abrams garage workshop project. The only reason I want to store sheet plywood up there is because I understand it should be stored flat.. and I just don't have the room to store it on the garage floor. It won't stay there long.. just long enough to complete my next project.. which is built ins for my small study. Thanks again, gents.

   bill