Simpson strong-tie

[bluedog225]

When I’ve dug into the Simpson publications, it says something like “don’t mix fastener types.“ That is, don’t mix their screws with joist hanger nails. And some of the simpson hangers specify nails.

I’m not arguing, but I am curious why they would have this requirement? During my build, various hangers did have get mixed fasteners. I’m not too worried given the loads on my hangers but wanted to understand this better.

Anyone know or care to speculate?

 

[Hank11]

The fasteners are part of the engineered solution to the joint you're making. Some people consider them hard and fast rules, others think of them as suggestions. Common sense comes into play, but don't go too far with it.

 

[bluedog225]

I agree using common sense. I guess the shear is more important than the pull out.

Though it would be nice if Simpson were a little more user friendly. As in calculating the reduction in strength using nails and screws.

Reminds me of the simpson instructions for predrilling nail holes. I recall it said you could drill 7/32 pilot holes. Not 1/8”. Gotta love the engineers.

 

[Firebrick43]

When I’ve dug into the Simpson publications, it says something like “don’t mix fastener types.“ That is, don’t mix their screws with joist hanger nails. And some of the simpson hangers specify nails.

I’m not arguing, but I am curious why they would have this requirement? During my build, various hangers did have get mixed fasteners. I’m not too worried given the loads on my hangers but wanted to understand this better.

Anyone know or care to speculate?

Because fasteners need to work together and share the load equally. If they are not all the same and there are a few of a harder screw and the rest nails the screw is likely to be loaded first and therefore overloaded and fail. At that point the other fasteners (nails) will receive the load but now they have to more load per nail as the screw having failed isn't doing anything.

These principles apply to all fastened joints whether bolted or screwed. You don't mix and match grades or sizes as they will not share load equally.

Reminds me of the simpson instructions for predrilling nail holes. I recall it said you could drill 7/32 pilot holes. Not 1/8”. Gotta love the engineers.

It affects pull out force. The way a nail interacts with wood fibers being cut and bent over is pretty well known. If they are not bent over the nail does not function correctly. Its not as if 7/32 drill bits are hard to find or use? They do these things with the hope of keeping you and your family safe from structural failures.

Even the shape of the nail and coatings have a huge impact on pull out forces.

 

[Rusted Nut]

Simpson tests certain pieces of hardware with a particular fastener; while other combos may work, other combos will not be an “approved, tested” assembly.

 

[bluedog225]

Thanks for the explanation. Makes sense. And I 100% agree on the drill bit. I’m sure it’s the correctly calculated size and that’s what I used.

 

[bluedog225]

And I see I messed up my math. I was going from failing memory.

 

[theoldwizard1]

The fasteners are part of the engineered solution to the joint you're making. Some people consider them hard and fast rules, others think of them as suggestions.

I am amazed at how many people use common nails for these !

 

[MikeC55]

It seems like it would be hard to abide by that rule if they don't offer of choice of bracket design per fastener type for a given type of joint. What are you supposed to do if you need a specific type of joint in one area that isn't offered in the fastener type you're using everywhere else?

 

[Hank11]

Lots of houses were built before metal hangers existed and many are still standing today. It would probably take more skill and knowledge than some of today's workers may possess to build the old way, so hangers to the rescue!

 

[bluedog225]

It’s a system so I use the specified fastener. And I spend the money on the simpson brand fasteners when I use Simpson brackets.

 

[nadogail]

When you combine a committee of Lawyers and Engineers, you will probably get a detailed CYA set of instructions.