Overdriven nails in wood sheathing

[abusementpark]

I've noticed that most people who fasten wood wall sheathing to studs tend to overdrive the nails. Is there a good way to prevent this from occurring? And is a certain amount nail overdrive tolerable?

 

[msquared48]

Back off on the settings for the powernailer.

Overdriving is not critical for non-shearwall areas, but if this happens too much, the strength of a shear wall is compromised and may require the sheathing to be replaced and properly nailed.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Ron]

In natural wood, there's greater damage to the wood fibers, resulting in more deterioration at the site of the overdriving, but usually associated with moisture as well. In "engineered" wood, there is less concern about wood damage, but as Mike noted, the localized strength is compromised. Say you overdrive by 1/16 of an inch...your effective thickness of the sheathing is reduced by the depth of overdriving (well, sort of...it's a little more complicated than that, but essentially that's the gist)

Fastener pull-over strength is reduced as well.

 

[ToadJones]

I was a guilty party for years.
Mike has the right idea, but it is nearly impossible to implement with OSB.
Different areas on the OSB are harder/ softer. You might nail one area and blast the nail all the way thru and then in another area have to pull out your hammer and set the nail. It gets very annoying and time consuming to have to keep setting the nails. So, most guys set the gun to counter set the nail a bit.
With ring-shank nails, I dont think it matters much. Tearing off sheathing that is nailed on with ring shank nails from an air nailer is a pain in the ass.

 

[a2mfk]

Also, in my experience, anyone with a nail gun shoots about double the nails that your drawings indicate... So that is a little feather in your cap so you are not kept awake at night pondering over-driven nails

 

[ToadJones]

a2mfk is correct.
and, most contractors ignore nailing schedules.

 

[mmillerpe]

APA has a technical topic on the subject, TT012-A. You can get as a free download at

http://www.apawood.org,

but you will have to register to get it. In short if all nails are less than 1/16" overdriven in dry conditions, things are OK. You can also have up to 20% of the perimeter nails up between 1/16" and 1/8" and still be OK. There is additional discussion in the Technical Topic.

 

[a2mfk]

Yep Toad, after my first trip to a site where I had all kinds of nifty nail schedules and saw them nailing the hell out of everything that wasn't moving, I gave up on that idea. Ever since I only call out one fastener and one spacing for the roof, one for the wall.

 

[dcarr82775]

My experiences do not match a2mfk and ToadJones. No matter what I specify I get 6" nail spacing, and always the wrong size nails.

If the framer is overdriving the nails badly in OSB sheathing it destroys the edge of the panel. In my mind the panel isn't worht much at that point. After you them remove and replace a few decimated panels I have found they can drive the nails relatively flush on a consistent basis.

I like Rons approach of reducing the thickness to account for the overdriven nail

 

[DKEngr]

Rule of thumb in the old days---up to 1/16 over-OK, 1/16 to 1/8-add (1) nail for each two over-driven, over 1/8-discount nail. Becomes a problem with a lot of overdriven in heavier nailing---risk too many nails in framing.

I think it is more of a concern with ply than with OSB. Once the face lam of ply is broken I think the capacity is degraded. If the guys know your inspector is going to climb on the roof and actually do the inspection, they'll do better. Talk to the building department.

 

[ToadJones]

Let me be clear that as a framer I took pride in my work and did my best not to overdrive, but it happens, especially in OSB. We always hand-banged seems.
On floors it was glue and nails and with newer style super hard sub floors like Advantech, no need to worry about over driving.The stuff is hard as hell.

 

[dhengr]

ToadJ.... no matter how you try to explain it, you are still the guilty party!

 

[a2mfk]

I guess I have a "show me the bodies" approach to nailing of shear walls, as I have yet to see a failure attributed to nail problems with a shear wall. Not to say it cannot happen, but I am in wind country and not seismic country, so every failure I have seen has to do with the roof. Now multi-story wood framed in seismic country, then I would be more concerned.

I am not saying it is OK to let stuff slide, use your own judgment on your projects, but as far as stuff that makes me toss and turn at night, it is very far down on my list. It would be great to see a structure designed and built so well that all the uplift straps worked and the roof stayed intact but you had buckling or failure of a shear wall. Maybe during one of those big full-scale shake table tests...

 

[BAretired]

Sometimes with wood deck on trusses, nails miss the top chord completely. Inspection below the deck reveals, in some cases rows of nails five or six feet long which missed the truss altogether. It is not always easy to check whether more nails were added in the correct location.

BA

 

[ToadJones]

dhengr-
I'll simply say this, if I had a nail blow thru, or was set too far, my immediate natural reaction was to re-nail correctly. I was still guilty of setting some nails too far. That's simply the nature of the beast.
Now, what no one should expect is a contractor who is trying to make a buck like the rest of use to take an extra week on the job nailing to a precise schedule and to exactly the right depth. Meanwhile the building is wide open and exposed rain and snow.

 

[dhengr]

ToadJ.... no matter how you try to explain it, you are still the guilty party!
*******
BA... they should at least clinch those rows of nails to improve their holding power, otherwise where’s your faith in the carpenters, in questioning that they didn’t add more nails. They probably used the wrong size too, because today’s carpenter understands penny weight to mean length of nail, dia. be damned.

Toad... In earthquake country, some inspectors count the nails, check edge distance and spacing btwn. rows and within the row and use a small straight edge to look at head depth. The code or EoR give the schedule. Some builders have taken to snapping chalk lines and marking the spacing on each sheet to save the fight during inspection.

 

[ToadJones]

dhengr
I plead guilty to the charges I brought upon myself earlier in the thread. I will now bring you up on charges of dead-horsing.

Most OSB sheets and some plywoods have the grid printed on them.

After putting down decks, I used to go into the floor below and drive any missed nails back up thru the top and remove them. Then I would go around telling everyone how great I was at nailing down sheathing.