Strap inspection

[ICE]

The contractor wanted to make sure that I saw the straps before he covered them with sheathing. When I told his 15 year old daughter {the translator} that the straps must be removed and placed over the sheathing, I could see in her eyes that she didn't relish telling him. It's a machismo thing.

 

[mark handler]

... that the straps must be removed and placed over the sheathing...

The straps could remain, and new ones placed on "other" rafters, over the sheathing. There is nothing that prohibits straps as shown.

 

[ICE]

The straps could remain, and new ones placed on "other" rafters, over the sheathing. There is nothing that prohibits straps as shown.

How would the sheathing be nailed where the straps are and if they were left in place, why would more straps be required? I suppose the missing 12" of sheathing nails is not that big of a deal except perhaps where panels abut however, the corresponding bulge would be visible. Well maybe only to me.

Come to think of it, there's probably not a code section that I can apply other than that the plans show the strap over the sheathing. Who am I to say no to bulges? Well there is always the next time.

It's not too late, the permit is in my truck, I could call him and correct the correction. But then he has seen the plans where I pointed out that the strap is on top. He might get the idea that I am a goofball. He might be right about that.

 

[Mark K]

The only basis I can see for requiring the straps on top of the sheathing would be if they were called for by the construction documents. In that case I would defer to the engineer who specified them.

I see no reason why they could not be nailed directly to the rafter and in fact in some situations the connection might be better if connected directly to the rafter.

The bulge is a visual issue that I doubt would be noticable after the shingles are in place. Note if the strap were on top of the sheathing they would get in the way of the roofing nailing.

The possible loss of sheathing nailing to the rafter should not be a concern unless the roof nailing was very close or unless you were in a hurricane zone.

 

[4thorns]

Is it possible that the straps over the sheathing are to be placed over every other rafter pair, missing the straps that are attached to the rafters themselves?

 

[4thorns]

I see no reason why they could not be nailed directly to the rafter and in fact in some situations the connection might be better if connected directly to the rafter

Not sure why it was called out over the sheathing unless it's in a high wind area. I've seen Simpson ties designed to tie opposing rafters together as pictured. If it's high wind then putting every other one on the rafters and the others over the sheathing to help keep it down seems to make sense.

 

[fireguy]

How many nails can you put in a 2X w/o splitting the wood? Or comprimising the strength of the wood?

 

[Rio]

The main problem with putting the straps under the sheathing is when you go to nail off the sheathing you can't get any nails into the rafter in that area without resorting to driving them in at an angle and hoping they'll catch; also when you drive in the nails like that they're either sticking up or bent over or the heads are pounded into the sheathing. The bumps might get picked up by the paper or possibly by adding pieces of felt judiciously to even out the dips but definitely a PITA.

 

[mark handler]

The main problem with putting the straps under the sheathing is when you go to nail off the sheathing you can't get any nails into the rafter in that area without resorting to driving them in at an angle ...

Just like any other strap or metal framing device installed prior to sheathing.

Ever Tried to nail a shear panel to a post cap?

Not an issue

 

[mark handler]

And toe nailing the sheathing or not putting in the two nails (assuming two) or adding a nailing block to the side of the rafter would be better than ripping out all those nails and straps, putting on the sheathing and renailing the straps to the same rafters.

 

[TJacobs]

Looks good to me...just like the diagram in the WFCM.

 

[mark handler]

By the way, Ridge straps OR collar ties, not and

Simple fix, leave it and add ties.

 

[TimNY]

Install the plywood and place the straps over the plywood on every other rafter. I assume the plans call for them 32" OC, so abandon what you got there and install compliant on the the other rafters. Drill thorugh the old straps to secure the plywood (although a framing nailer will usually punch through 18 or 20 ga)

You cannot create new holes in the straps (Simpson catalog says this multiple times) and the roof diaphragm must be nailed per the schedule.

Tim

 

[4thorns]

Tim, any thoughts of why the plans called out the straps over the sheathing. I've seen several details where the straps tie opposing rafters together over the ridge but never over the sheathing? Seems like this detail would reduce the straps effectiveness by introducing extra shear.

 

[TimNY]

In my personal opinion, most designers fail to recognize the practicality of what they design. For a ridge strap it's a minor oversight, but for some of the wall straps (I had one home with a 8' long x 3" wide strap at the corners) it's an impossibility.

There are two things that must happen to comply: 1) You cannot create holes in a a strap pursuant to the manufacturer's instructions. 2) You must nail the plywood as per the cladding diagram.

In any scenario I've ever seen, it is impossible to nail the plywood per design without punching holes through straps under the plywood.

When you place Simpson straps over plywood (can't speak for other brands, but likely it's the same) you must use a 2-1/2" nail (p16 of the Simpson manual), which presumably counteracts the issue you pointed out.

 

[brudgers]

How many nails can you put in a 2X w/o splitting the wood? Or comprimising the strength of the wood?

You can put nails into wood until the wood splits.

 

[brudgers]

There are two things that must happen to comply: 1) You cannot create holes in a a strap pursuant to the manufacturer's instructions. 2) You must nail the plywood as per the cladding diagram. In any scenario I've ever seen, it is impossible to nail the plywood per design without punching holes through straps under the plywood.

Typical edge spacing of nails is not going to affect strap integrity to the point where it should be tagged.

 

[TimNY]

You would need to address that with the manufacturer. They are very clear that you are not to create holes in their product.

How many nails were put through, how big, how long is the strap. Where in the strap did the nail fall. Easy answer is you cannot put holes in the strap. Practical answer is you'll know it's wrong when you see it.

If you are nailing a shearwall at 3"oc edges and you have a strap 24" up the stud, you have an issue.

 

[brudgers]

You would need to address that with the manufacturer. They are very clear that you are not to create holes in their product.How many nails were put through, how big, how long is the strap. Where in the strap did the nail fall. Easy answer is you cannot put holes in the strap. Practical answer is you'll know it's wrong when you see it.

If you are nailing a shearwall at 3"oc edges and you have a strap 24" up the stud, you have an issue.

You're not nailing a shearwall - it's a ridge strap which requires (3) 8d - thus providing a minimum of ~210 lbs of shear strength with "Northern Species" (IRC 2006 & NDS 2002).

An LSTA strap is 20ga (.033") x 1.25" ASTM A653 with a tensile strength of 58kpsi

Thus, ultimate strength is 2400 lbs giving 480lbs @ 5:1 safety factor.

So, if you only have holes comprising half the width of the strap, you still have 14% excess capacity at a 5:1 safety factor.

Again, it's not a shearwall and common sense should prevail...although I know how much more difficult that can be than just saying "no" in lieu of educating one's self.

 

[TimNY]

a) you need to be an RDP to calculate what you just did.

b) you stated generally "typical edge spacing"; I replied with a typical scenario.

c) I know it's not a "fkn shearwall", we are following post 14, which was a general question. If you are back on the specific topic at hand, better to state clearly, as I did.

d) I stated "you'll know it's wrong when you see it". Think about that statement.

e) While I did give an out in "d", gIven your attitude, I think I'll stick with following the instructions, lest I see a 1/2" lag bolt through the next strap. Not following instructions is a clear violation and no letter from you to my boss, your assemblyman, senator, AIA chapter will overrule that.

Think about doubling up on your lipitor.

 

[mtlogcabin]

2009 IRC

Collar tie rafter, face nail or 11/4" ×20 gage ridge strap 3-10d (3" × 0.128" )

The code does not say how long the strap is or that it needs to be a manufactured/engineered strap.

By placing the sheating over the straps you will install 1 more nail maybe 2 depending on the length of the strap, I believe some are over thinking this one.

 

[brudgers]

2009 IRC Collar tie rafter, face nail or 11/4" ×20 gage ridge strap 3-10d (3" × 0.128" ) The code does not say how long the strap is or that it needs to be a manufactured/engineered strap. By placing the sheating over the straps you will install 1 more nail maybe 2 depending on the length of the strap, I believe some are over thinking this one.

I'd say it's more a case of underthinking...

 

[brudgers]

a) you need to be an RDP to calculate what you just did. b) you stated generally "typical edge spacing"; I replied with a typical scenario. c) I know it's not a "fkn shearwall", we are following post 14, which was a general question. If you are back on the specific topic at hand, better to state clearly, as I did. d) I stated "you'll know it's wrong when you see it". Think about that statement. e) While I did give an out in "d", gIven your attitude, I think I'll stick with following the instructions, lest I see a 1/2" lag bolt through the next strap. Not following instructions is a clear violation and no letter from you to my boss, your assemblyman, senator, AIA chapter will overrule that. Think about doubling up on your lipitor.

You don't need to be an RDP to do it...I know for fact, because I would do them before I was one when I worked behind the counter. You don't need to be an RDP to apply common sense either...

But when you're behind the counter, then again, you probably don't need to either...

for it may interfere with the pleasure one derives from abusing one's power.

 

[Papio Bldg Dept]

...for it may interfere with the pleasure one derives from abusing one's power.

Well, how'd you become king, then?You can't expect to wield supreme power just 'cause some watery tart threw a sword (or rafter ridge strap) at you!

Sorry, couldn't 'elp me-self.