[shuuy]

So it's been as hot as balls in Toronto - just like the rest of the Midwest I'm sure.

We live in a 90yr recently reno'ed semi. The previous owner reno'ed and put our master bedroom into the top floor (previously the attic?).

Just noticed this morning that a piece of drywall fell off, exposing a rusted screwhead which I assume goes into the rafter or something to that effect.

I can easily patch the hole and paint, but I'm wondering if it is something more serious than that? Drywall falling out by a screw? In the attic? Rusting screwhead?

I notice it on other parts of the ceiling as well (see attached photos).

Appreciate any advice!

 

[TrapperL]

We call those nail pops. You said that it was a screw under it though. Usually a nail pop is caused by the nail being loose and not holding the drywall tight. If the screw has broken the paper facing or if the screw is not holding the drywall tight you'll get this. I'd suggest taking another drywall screw and putting it about 2" on either side of the nail pop. Do the cosmetics and that should take care of the issue.

 

[shuuy]

Thanks for the response. Would it be common for this to happen in multiple places? It's in about 5-6 spots.

 

[TrapperL]

In my many years at QC, usually when you see one, there are others as well. It's more a matter of the guy that worked the job didn't have the expertise to do it correctly or maybe he was having another Monday. But I would expect you see more than one.

 

[Gary in WA]

Was the wave in the ceiling always there? It could be due to excessive moisture from the winter if the attic isn't vented properly, rusting the screws from the attic side. Or, the ceiling never was secured correctly, spacing, length of screws, etc. Check on the attic side for a vapor barrier plastic on the drywall under the insulation. Check here for correct fastener requirements to compare;
http://gypsum.org/pdf/GA-216-2010.html

The application could also have been flawed; http://www.paintsource.net/pages/solutions/new construction/wood_shrink.htm

Gary

 

[shuuy]

The moisture is what I'm worried about.

Is there a non-destructive way to test whether the vapour barrier is functional? (ie without ripping drywall or shingles down?)

 

[TrapperL]

The nails/screws are going to be rusted. They are installed so that the head is recessed into the drywall so that when the float takes place it covers the nail/screw. This is a wet application and causes the rust. Even in our desert lower country along the border with Mexico you'll see the fasteners rusted on nail pops.

Yes you can check the moisture in the drywall with a moisture meter. In your area I would think that to be a fairly common tool, but I doubt you're going to find any excess moisture. In Texas, when we have a moisture problem the first thing that gives you a hint is the tape on the drywall starts to crack open and will eventually peel. The texture and float also starts to crack and peel. I don't see that in your pics, just a common nail/screw pop