PFH Nailing Requirements

[Medeek]

With the PFH method of wall bracing it requires that the sheathing is nailed to all studs, blocking and sills at 3" O/C with 8d common nails.  Fair enough but what about the situation where you have 5 studs all next to each other.  Doesn't this amount of nailing seem excessive?   Couldn't one just nail every other stud (3 of the 5) since I am already exceeding the minimum 2 studs required for a portal frame.  Detail drawing of the panel in question shown below:

[MountainDon]

    You would think so, wouldn't you?  Nailing all five like that seems excessive. Wonder what (the other) Don has to say?  He may have been there, done that. 

[Don_P]

Sure sounds a tad overnailed. My state has modified the bracing section from stock but I haven't compared it to the model code, so a grain of salt. They do want it to be a solid unit but my read is 3" oc on the minimum 2 pairs of studs. Have you checked the APA's portal frame guide? The engineer at their helpdesk has always responded to queries within a day when I need something fleshed out.

[Medeek]

That was kind of my thinking, the code calls for a min. of two 2x4 studs, so if you nail at least two of these off with the 3" o/c it would seem to be in compliance and then maybe a third for good measure.  Above and beyond that seems gross overkill to me, granted it would be strong, , even a 150 mph hurricane would probably not knock those walls apart.

Thanks for the contact, I'm going to shoot this over to APA's helpdesk as you suggest and see what he suggests.   I know what I would like to do with this but if I'm strictly following the code I end up with my overnailed mess.  Hopefully he can shed some light on what is within compliance but still reasonable.

TT-100 is the APA Portal Frame Guide.  Pretty much mirrors the IRC as nearly as I can tell so it doesn't really shed much light on the situation with 2+ studs.

[flyingvan]

Per my inspector (so same grain of salt)--- I never had to have any nails closer than 3" from each other in any direction  "So, what you're saying is, if I go 3" OC on the outer studs, then fill in the middle in a pattern where they are 3" away from each other I'm good?" He just repeated the exact same thing again---- I didn't have to have any nails closer than 3" from each other.  Ended up with a zigzag pattern.  It makes some sense----at some point, too many nails will weaken the panel

[MountainDon]

... or turn good studs into toothpicks

[PEG688]

IMO that type of nailing pattern is stupid, but arguing with a building official is as they say like wrestling with a pig , you both get dirty , but the pig likes it.

[Medeek]

Response from the APA Help Desk:

Although 2009 IRC Figure R602.10.3.3 states "... 3" o.c. IN ALL FRAMING ..." the method is based on a minimum of two studs per side (four studs total) of the vertical element. Therefore the intent is that the required sheathing fastening is 3" o.c. into the two outside studs (the two studs that form the perimeter of the wood structural panel) on each side of the PF. Fastening into additional studs that may be necessary for other reasons is not required because those additional studs are not required for the PFH bracing method.

I hope this information will be of assistance to you.  Please let us know if we can supply you with further information.

I suppose that makes sense, pretty much inline with what everyone else here is saying. 

I'm assuming that I can then remove some of the redundant nailing around the perimeter of the portal frame but since this particular portal frame is 30" there is that middle stud.  I'm thinking that would keep the 3" o/c nailing pattern.   I will post up a new detail drawing of the updated nail pattern and lets see if I can get this right.

[Medeek]

Updated Nailing Patterns for the three portal frame/separators in question.  I think these are little more reasonable.  I am a little unsure what the nailing requirements are for the jack studs (single portal frame) on the other side of the portal frame.  I've gone with 6" o/c.  The IRC and APA don't specify any nailing pattern on these studs (FIG. 602.10.6.2).

[Don_P]

The wider the "column" the stronger, and you understand how the stress is concentrated toward the edges, so I'd nail the jacks well to keep the column as wide as possible. The field nailing is simply keeping the sheet from buckling as load is applied in plane.

Don't specify nails by pennyweight alone, give a min length x dia. Pennyweight has become about useless.