Replies

1. 
   roqqytop | Mar 29, 2009 10:03pm | #1

   Most screws have shear values of 60# or more.
   10p nails about 130#.

   Hit the STUDS in the wall is the important factor.

   If you want to get fancy, use 3" course dry wall screws and plug the holes.

   Other option would be long finish screws.

   WEIGHT is not a factor here!

1. 
   stewie | Mar 30, 2009 04:19am | #4

   Thanks roqqytop The wall is 24" centers, so , on the 30" length , I can get a stud 24" from the corner. The plan is 2 #10 screws 3" long so I get 1 1/2" in the stud. On the shorter side ( 18" ) there is a stud 15" from the corner , so 3 more #10s. I think I can also get a couple in the corner of the wall. With the plywood behind the drywall ( screwed in) I can add some 2" # 10s. Should be solid as a rock, eh?Stewie

1. 
   roqqytop | Mar 30, 2009 08:46pm | #6

   If you have plywood behind the dry wall, hitting the studs is NOT necessary............unless you plan on adding 2-300# of additional weight.But the rule of thumb for fasteners always holds true, if you are not sure, add some more.The same goes for Joist hangers in framing.
   Most framers just fill all the holes (hopefully with N10 hanger nails) to be safe.
   A couple years ago I had a Professional Engineer inspecting the framing of a large new home I was building and he asked WHY there were only 6-7 nails in the I-joist hangers?I looked up, (and in less time than it will take to type this)
   and said, well................ the joist span is 12 feet, thats 6 feet to the hanger end and on 16 inch centers @ 50 PSF that is 400 lbs of design load. Each N10 nail carries 140# each, so 6 nails will handle 840# giving me a FOS of +2.He says: how do you know each nail holds 140#?
   Answer - because thats the design value and has been for the last 15 years I have used them.Needless to say - the guy with the PE's license was no more trouble - the same guy that asked for Beam calculations for all 16 LVL beams because the house was enlarged.
   I quickly pointed out that what about the original plans (that would have been fine, if not enlarged) and the Architect that was attempting to sit a 7 inch wide x 11 7/8" high beam on a 2 x 6 wall.
   I said - most intelligent people would have sized a 3 1/2 x 16' tall LVL and built it up into the 2nd floor 2 x 4 exterior wall saving MONEY on material. He had no answer, but had the paper.SOME PE's operate at about 40 watts voltage.
   He just dropped his head the day I dropped off the beam calculations as I told him, I missed my goal by 5 minutes, it took 65 minutes to hand write all 16 with diagrams. Obviously, that was before the hanger question. Some PE's are slow to learn.

1. 
   dgreen | Mar 30, 2009 09:20pm | #7

   40 watts voltage

   I hope you don't do your own wiring! 

    

   ................................................

   Men will never be free until the last king is strangled with the entrails of the last priest.~ Denis Diderot

1. 
   roqqytop | Mar 31, 2009 12:06am | #8

   yeah, thats pretty funny and I realized it after I posted it; however,
   I think my point was made.to answer your question, 20 years ago couldnt wire a flashlight.
   Biggest job to date - 4000 + sq ft house with 200 amp main and 2 - 100 amp subs. Around 45 circuits and 4k wire. Interesting detail of that job - the MAIN electric panel was hooked up with only about 1/3 of the framing completed. Framed up an 8 foot section of garage wall to hold the meter base and called the inspectors just as the electric company came. Even had a small roof over the main panel box in the basement mechanical room. EZ PZ JapanEZ!

2. 
   Cincinnati | Mar 29, 2009 11:59pm | #2

   Are you saying you have 3/4 plywood nailed or screwed to your studs and drywall covering the ply? Or is your shelf an angle bracket design with ends?

   If possible, I would use a French Cleat design. Screw a cleat with a 45° bevel facing upward to the wall. Hang the shelf off this cleat.

   Greg

   •••••••

   Exo 35:30-35

1. 
   stewie | Mar 30, 2009 04:29am | #5

   Hi Greg Yes, when the house was being built , I added 3/4" ply between the studs as a backer for the future TV. Screwed it in. Shelf is rectangular. 30" X 18". and 9" deep. I recyled an earlier shelf I had made for the same purpose by taking it apart , taking the finish off with the planer , and re-constructing it with a finish to match the new room. The initial shelf had sat on the dresser, so I didn't have the issue of hanging it on the wall. " It worked before , it'll work again , and I don't like throwing my projects out. Thanks for the french cleat idea. I have used that before for a large picture, but did not think of it for this. CheersStewie

1. 
   Cincinnati | Mar 31, 2009 04:54am | #9

   Since you had forethought to add the plywood, I suppose it is well anchored to the studs— ie: with an additional nailer, not toe-nailed to the studs and not anchored with drywall screws. I have heard horror stories of upper cabinets falling off the walls a few years after they were hung with drywall screws.Greg

   <!---->•••••••

   Exo 35:30-35<!---->

3. 
   BruceS | Mar 30, 2009 12:22am | #3

   Remember!  Drywall screws are not designed for shear, even says so on the box. 

   Work Safe,  Count to 10 when your done for the day !!

   Bruce S.