Sheetrock damage - Nail popping 1

[msquared48]

Anyone ever heard of an unpatterned nail popping in walls occurring in multiple locations in an old residence after new vinyl windows were installed?

I could attribute it to a humidity change, due to the new windows, possibly related to the type of nails used, but it seems a stretch.

Mike McCann, PE, SE (WA)

 

[Archie264]

It sounds to me like the new windows changed the stiffnesses of the walls. Now, as loads are hitting the structure (wind, temp. changes, settlement, etc.) the stresses are being resolved along new paths and revealing said paths with the popped nails.

No, I haven't specifically heard of such, per se, but it wouldn't surprise me. I've come to the conclusion that despite our best efforts, only the house itself truly knows the entirely of its load paths.

 

[jayrod12]

Archie makes a fantastic point. I would bet the old windows that were removed had the sills framed directly to the structure, i.e. no insulation gap. Once removed, that opening is not as stiff as it once was.

 

[JAE]

Mike - are the nail pops near the windows?
Did you replace old windows with new or are these new windows in walls that were previously without windows?
Did the existing wall have headers over the windows? (some very old carpentry I've seen didn't use headers of any significance)




Check out Eng-Tips Forum's Policies here:
faq731-376

 

[Ron]

Mike...you're on the right track. Humidity reduction from better windows. Drywall shrinks...nails don't.

 

[msquared48]

JAE and Ron...

Thanks. The windows are new to existing openings. The structure was not changed. Crack appeared at one end of an 8 foot window, but not the other end.

Nail popping is random at both interior and exterior walls, leading me to the relative humidity issue.

Mike McCann, PE, SE (WA)

 

[msquared48]

Relating to the crack at the window, it makes sense if the old window was framed tight to the underside of the header, but the new window was not. The header is now allowed to see more deflection. Hence end rotation in the header and rhe crack in the sheetrock..

Mike McCann, PE, SE (WA)

 

[JAE]

Good photos of wicked cracks are always fun to look at .... do you have any?


Check out Eng-Tips Forum's Policies here:
faq731-376

 

[DBronson]

msquared48:

Did the installer flash the windows properly? Rain water could be entering the wall and causing "moisture problems". Very tricky to flash new windows without removing a lot of the cladding material.

Regards,

DB

 

[msquared48]

JAE... yea, at work. I'll post it tomorrow.

Mike McCann, PE, SE (WA)

 

[msquared48]

Here is one picture of the crack at the end of the 8 foot window header:

This shows the top condition...

The next post shows the condition at the bottom of the window. This implies an obvious shift in load with the possible crushing or load consolidation as there is no distress at the foundation seen, inside or out.

Mike McCann, PE, SE (WA)

 

[msquared48]

Here is the condition at the bottom of the window:

Mike McCann, PE, SE (WA)

 

[jayrod12]

I could see the upper one happening removing an old tightly framed window. I don't quite get the one at the bottom of the window. That to me means more load is on the bottom sill than used to be, I guess the new windows likely weigh significantly more than the old.

 

[msquared48]

...Unless the old window utilized a center load bearing mullion, but the new one does not, shifting load to the end, causing new consolidation.

Mike McCann, PE, SE (WA)

 

[msquared48]

Nail popping pictures: First is outside wall, second is inside...

Mike McCann, PE, SE (WA)

 

[msquared48]

Here is the second - could also be an old molly-bolt location that was never removed too.

Mike McCann, PE, SE (WA)

 

[jayrod12]

I would expect a dead vertical crack at the middle of the wall above the window then as the lintel sagged with removal of the mullion.

 

[msquared48]

True. I will check...

Mike McCann, PE, SE (WA)

 

[msquared48]

No crack noted midspan. HMMM...

If the header rotated down on the end of the cracking seen, then additional cracking should have been seen at the opposite end with a crack at the other end. That was not seen.

Gremlins, that has to be the answer...

Mike McCann, PE, SE (WA)

 

[Archie264]

Jayrod12, thank you.

Msquared48, if I understood you correctly that the popped nails have appeared on both the inside and outside then I doubt it's a moisture issue.

When I redid the flooring in my house, when I pulled the baseboard off the floor in one room a large Z-shaped crack formed in the wall. Up to that point the baseboard had apparently been serving as some sort of tension tie on a volunteer basis. The crack is not causing any problems beyond being unsightly, but it wasn't caused by gremlins.

If the situation's no worse than what you've shown in those photos then I wouldn't give it another thought. However, if you want to address it one approach might be to give the situation a few months to allow whatever settlement that might occur to occur, then use a nail-setting punch to countersink the nails to whatever degree possible, then putty and paint. Remember: putty and paint make a carpenter (and structural engineer) what he ain't.