Replies

1. 
   CloudHidden | Oct 26, 2003 04:08pm | #1

   Won't vouch for the veracity of the answers, but here's some that address it.

   http://www.hammerzone.com/archives/letters/decks/hangers_n_screws.htm

   and another

   "Can I use deck screws to fasten the joist hangers? No, you should always use a special galvanized joist hanger nail because it is stronger, and won’t shear under pressure. Many screws are made of a soft metal."

   and finally

   http://www.strongtie.com/products/connectors_list/sds.html

2. 
   RichMast | Oct 26, 2003 07:29pm | #2

   Here is something from the strongtie site FAQs http://www.strongtie.com/faq.html 

   Q: Can I use nails other than what you have specified? How about using screws instead of nails?

   A: Some of our connectors (generally straight straps and face mount hangers) can be installed with alternative fasteners but usually with reduction in load capacity. Please refer to the Simpson Strong-Tie catalog or this chart for a list of viable substitutions. As for screws, because of their smaller shaft diameter and shorter penetration distance they usually have lower shear capacity than common nails. This is not to say that you can not use screws with our connectors. Just keep in mind that there is going a reduction in the published load values, and if this reduction is acceptable, then there should be no problem using them.

3. 
   BossHog | Oct 27, 2003 03:13pm | #3

   I don't know of any code that prohibits them.

   The hanger fasteners are specified by the hanger manufacturer - Not codes. The size of the fastener is called out based on their testing and design requirements from the NDS.

   Keep in mind that the shear value of the screw isn't what's important - It's the DIAMETER of the shank. The wood is softer than the metal in the screws, so you need the larger diameter shank of the nails to spread the load out over a wider area of the wood.

   I suspect that the screw manufacturers aren't willing to stick their neck out and specify load values for their screws due to liability concerns. And the hanger manufacturers have no reason to want to go through the necessary testing just to specify something they don't sell.

   Give a man a fish; you have fed him for today. Teach a man to use the Net and he won't bother you for weeks.

1. 
   CloudHidden | Oct 27, 2003 03:42pm | #4

   Simpson does make a screw, and there's a specific ICBO Evaluation report on it that approves it for certain wood-wood and wood-metal applications. The report concludes, "The use of Strong-Tie Series S wood screws described in this report complies with the 1997 Uniform Building Code."

1. 
   BossHog | Oct 27, 2003 04:12pm | #5

   The screws Simpson makes are 3/16" or 1/4" in diameter. They are intended for assembling mulit-ply girder trusses, not attaching joist hangers. (Unless they've introduced something I don't know about yet)

   I tried a search on the document you mentioned, but couldn't come up with it on the internet. Where dod you get the name from?Take Courage! Whatever you decide to do, it will probably be the wrong thing. [Ashleigh Brilliant]

1. 
   CloudHidden | Oct 27, 2003 04:38pm | #6

   Aha! I didn't see that explanation. Good clarification.

   http://www.strongtie.com/CustomerDB/Codes_Products.asp

1. 
   moltenmetal | Oct 27, 2003 06:47pm | #7

   If the joist hanger nails are the only option, what do the pros think about the option of using a pneumatic palm impact nailer to put them in?   Many people find it hard to swing with enough umph in the restricted space between the joists, and I've personally found the palm nailer to be worth its weight in gold- but I'm interested in other opinions.

2. 
   OneofmanyBobs | Oct 27, 2003 11:06pm | #10

   Palm nailers work.  Slower than a hammer, hard to keep short nails straight, but fewer pounded fingers.  I have a hammer with the claws cut off for small spaces.

3. 
   RW | Oct 28, 2003 01:16am | #11

   Palm nailers work fine. So do strap guns / teco nailers / positive placement / call them what you like."The child is grown / The dream is gone / And I have become / Comfortably numb "      lyrics by Roger Waters

2. 
   csnow | Oct 27, 2003 07:04pm | #8

   "Keep in mind that the shear value of the screw isn't what's important - It's the DIAMETER of the shank. The wood is softer than the metal in the screws, so you need the larger diameter shank of the nails to spread the load out over a wider area of the wood."

   I'm not so sure on this one.  Cheapo generic deck screws are very brittle and weak in shear. 

   Put some in a vise, and give them a whack.  They will snap. 

   Try the same with a nail, and it will bend, but not break.

   I do not think that ordinary deck screws should be used for any structural application.

1. 
   BossHog | Oct 27, 2003 07:51pm | #9

   "Cheapo generic deck screws are very brittle and weak in shear."

   I agree. But the value of the wood in compression perpendicular to the grain is less that the weakest meatal.

   "Put some in a vise, and give them a whack. They will snap."

   Whacking something doesn't simulate the kids of forces that nails or screws would be subject to in hangers.Non-conformists of the world unite

1. 
   Piffin | Oct 28, 2003 01:37am | #12

   There is something else that can snap them and is likely to in a hanger application. That is when the head of the screw is brought tight against the metal of the hanger suddenly by an over zealous helper without a soft clutch on the screw gun. The turning continues past the point of maximum stress because the threads are designed for wood/wood use.

   It's similat to when Sheet rock screws are used for hanging wall cabinets. The SR screw is designed for p[aper to wod and the head will snap off easy in hardwood instead of sheetrock.

   I noticed that earlier you said that it is not the shear that's important. Maybe not as important as the wood displacement but Simpsons writtings make shear strength a primary consideration..

   Excellence is its own reward!

1. 
   andybuildz | Oct 28, 2003 03:14am | #13

   so what your saying is that SR screws aren't made for fine home building <G>

   Kidding....or didn't ya know that?

   Personally I don't even know why this question is even being asked.

   Whats the big deal in using teko nails? Thats the right job!

   Be well fastened

                        andyMy life is my practice!

   http://CLIFFORDRENOVATIONS.COM

2. 
   CAGIV | Oct 28, 2003 03:17am | #14

   not to mention, takes longer to drive a screw then a nail...

   least I think so.

4. 
   dIrishInMe | Oct 28, 2003 03:21am | #15

   Well, to get an absolute answer, you would have to say what state, country, planet, you live in/on, since many different areas use many different codes...

   Generally though, the way all code officials I deal with interpret things, in the absence of very specific requirements in the code being applied, assuming you are talking about a safety (in this case structural) item, the xxx must be installed per manufacturer recommendations.   (xxx being whatever you happen to be installing)

   Our inspectors always look to see that all hanger nail holes are filled and sometimes to to see that the correct nails to be used - JH nails have a 8 or a 10 on the head, but I haven't had them complain about the use of 16s - which are pretty much the only way to go with the the of hangers that are the "toe-nail" type.  The idea is to guard against some hack or nim-wit who would use 8s or roofing nails.

   That said, I'm sure the inspectors I deal with would accept screws if you had an engineering letter.  In most cases though, common sense would go against going to that hassle...

   To get a definitive answer, rather than listening to a bunch of opinions (including my own), just call your local code enforcement official, ask the question, and be sure to get his name...

   Matt