Locating fastener schedule for sistering joists?

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Old 04-25-15, 08:20 PM
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Locating fastener schedule for sistering joists?

Where in the building code (2009) do I find a fastener schedule for sistering 2x12 joists?
 
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Old 04-26-15, 07:16 AM
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I'm not sure if there is a nailing schedule for sistered joists. Maybe Chandler or Czizzi knows.

From what I understand, it would be similar to building a header, 4 each 16d nails @ 16" oc.

If the additional joists have bearing area at both ends, then the nailing is less critical.
If you are repairing a joist, then bolts would be in order, 6" on center, staggered top and bottom, with washers.
 
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Old 04-26-15, 09:26 AM
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Thanks Handyone...

Would it kill them to add something about sistering joists - seeing how often it is done???

I'm guessing you are looking at Table 2304.9.1 Fastening Schedule - item 14?

Odd given the schedule under the residential code for built up beams is so much less and only 10d.

I hate that the nails will penetrate the other side. My basement is also my shop and I don't intend to put in a ceiling.

Is there anywhere in the code that provides for substituting fastener sizes? Something like thee 8d's = one 16d? I don't suppose so - probably an engineering issue.

Also, isn't it the gauge of the nail and not the length that provides the strength? I would think an 8 gage (same as 16d) nail that went thru one board and 3/4 of the way thru the sister would be just as good.
 
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Old 04-26-15, 09:46 AM
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I'd like to see Chandler's input. Maybe I'll PM him. And yes, I'm looking at item 14.

Why are you sistering the joists? I assume to stiffen the floor above.
Will these additional joists have any bearing area at ends?
 
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Old 04-26-15, 09:54 AM
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I am fixing a cracked joist. The sister has full bearing on both ends. It is the same length as the existing joist.

Truth be told, I'm just doing it to make it right. The floor above seems fine but the joist looked real bad. I'm a sucker for punishment.
 
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Old 04-26-15, 09:58 AM
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Just got home from church. Sistering joists takes more common sense than prescribed nailing. Using a good glue, such as PL8X between the two, placing the crown up and screwing the joists, preferably from both sides with 3"x #9 torx decking screws at a slight angle so they won't protrude at about 6 to 8" intervals in a W form will form a good bond. As Brian stated, if the ends are supported, it is stronger, but if repairing, the screwing sequence as well as the good glue will hold 'em.
 
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Old 04-26-15, 10:03 AM
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Since the joist ends are bearing, I wouldn't be too concerned with adhering to a nailing schedule.
Common sense comes into play and I would just nail it any way you desire.

Bolts and the like are advised when repair only extends 4' or so beyond the edges of damaged area.
 
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Old 04-26-15, 10:06 AM
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Thanks for the advice! I truly appreciate it!

Chandler - why do you recommend screws?
 
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Old 04-26-15, 10:23 AM
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You aren't into a "shear" situation, where nails would be prescribed. Screws have much less shear protection. I would use screws because of their holding ability and their "draw up" ability. Plus you don't have to bang them in. If you do choose to use nails, use ring shank nails, again 3" in #10 or so if you can find them. Also, if you use nails, I would use clamps to hold the wood together so it doesn't bounce too much while you are trying to drive them.
 
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