[tradertim28]

Hi, the images below show my ceiling. Above this is the attic. The ceiling feels like it's plasterboard.
Regrettably I had a rat in the attic and I couldnt get rid of it with normal means - so I had a "brilliant idea" (cough) to throw some bleach around and stink the critter out.
The bleach mainly landed on the foam insulation but some must have gone beneath.
The rat went, but...
About 6 months later these marks started appearing. They are getting worse.
I went up and cannot see a leak or any overt damage.
But the marks seem to be in a line and appear to be where the screws are going through the rail holding the plasterboard up into the plasterboard itself.
There is a silvery lining on top of the plastboard section, this looks OK.
Is there anything I can do about this --- will it just get worse and worse?
Thank you!

 

[ClarenceBauer]

Hi, the images below show my ceiling. Above this is the attic. The ceiling feels like it's plasterboard.
Regrettably I had a rat in the attic and I couldnt get rid of it with normal means - so I had a "brilliant idea" (cough) to throw some bleach around and stink the critter out.
The bleach mainly landed on the foam insulation but some must have gone beneath.
The rat went, but...
About 6 months later these marks started appearing. They are getting worse.
I went up and cannot see a leak or any overt damage.
But the marks seem to be in a line and appear to be where the screws are going through the rail holding the plasterboard up into the plasterboard itself.
There is a silvery lining on top of the plastboard section, this looks OK.
Is there anything I can do about this --- will it just get worse and worse?
Thank you!
View attachment 701665
View attachment 701666

If the Plaster coating is not missing over the nail head, you should be able to use an oil-based primer should stop the rust staining.
The nails used at the time that system was installed are the Blue coated Lath nails & will rust when in contact with moisture.
As for the silver lining on the back side that is an insulated type of gypsum Lath.

 

[tradertim28]

If the Plaster coating is not missing over the nail head, you should be able to use an oil-based primer should stop the rust staining.
The nails used at the time that system was installed are the Blue coated Lath nails & will rust when in contact with moisture.
As for the silver lining on the back side that is an insulated type of gypsum Lath.

Thanks Clarence.

The screws - they dont have a plaster coating over them when I look at them in the attic. They are just screwed into the plasterboard with the metal divider rods under them.

Do I need to put the oil-based primer on top of the screws, or paint it on the ceiling where the stains are? I'm worried about it getting much worse, as the rings seem to be getting worse.
Should I remove the screws - or is this likely to make the ceiling collapse in?

 

[ClarenceBauer]

Thanks Clarence.

The screws - they dont have a plaster coating over them when I look at them in the attic. They are just screwed into the plasterboard with the metal divider rods under them.

Do I need to put the oil-based primer on top of the screws, or paint it on the ceiling where the stains are? I'm worried about it getting much worse, as the rings seem to be getting worse.
Should I remove the screws - or is this likely to make the ceiling collapse in?

The stain is on the finished side of the ceiling, correct?
You should not have to do ant thing from the attic side.

 

[tradertim28]

Yes, the stain is on the finished side in my bedroom. You can see it on the photos above

 

[ClarenceBauer]

Yes, the stain is on the finished side in my bedroom. You can see it on the photos above

I would first use a primer than spackle if it is not as smooth as the surrounding surface.
All you need is to stop the moisture from getting to the screw.

 

[tradertim28]

Sorry but I'm confused.
Do I paint over the stain or the screw head in the attic? Or remove the screws?
(Painting over the stain won't affect the screw from oxidising will it?)

 

[Half-fast eddie]

The screws are rusting. At some point they are going to rust completely away and no longer provide support to that part of the ceiling. I would dig out the remains of the screw so it doesn't continmue to stain the ceiling, and then either run a longer screw into the same hole, or better ... run in a screw about 2" to the side. patch & paint.

 

[tradertim28]

The screws are rusting. At some point they are going to rust completely away and no longer provide support to that part of the ceiling. I would dig out the remains of the screw so it doesn't continmue to stain the ceiling, and then either run a longer screw into the same hole, or better ... run in a screw about 2" to the side. patch & paint.

OK, understood.

Is it easy to unscrew - bearing in mind I'm new to DIY?

 

[woodco]

I would just change the screws out altogether, and STILL dab ( or hit it with a rattle can) the area with a stain blocking primer to prevent rust from going through.. Bleach will destroy metal, it may rust right through the primers. Maybe not, but I wouldnt take the chance.

Better yet, sink a new screw right next to the old one first, then pull the rusty one out, rather than use the same hole.

EDIT, sorry Eddy said same the same thing I did.

 

[Half-fast eddie]

Is it easy to unscrew - bearing in mind I'm new to DIY?

It is here in the colonies. Just use a screwdriver. :}

Seriously ... use the tip of the screwdriver to chip the plaster off the head of the screw, then it's leftie-loosie. However ... you might find that the screw has rusted too much and there is no head left. In that case, grab the head with a pair of vice grip pliers.

 

[tradertim28]

Thanks everybody for your help

 

[tradertim28]

I would just change the screws out altogether, and STILL dab ( or hit it with a rattle can) the area with a stain blocking primer to prevent rust from going through.. Bleach will destroy metal, it may rust right through the primers. Maybe not, but I wouldnt take the chance.

Better yet, sink a new screw right next to the old one first, then pull the rusty one out, rather than use the same hole.

EDIT, sorry Eddy said same the same thing I did.

Are the screws standard size?
And to create a new hole next to the first one, do I need to drill into the plasterboard, or just screw in directly?

 

[woodco]

1 1/2" drywall screws most likely. screw directly in. Pro drywalls have a special bit that limits the screw head depth. You dont need it, but be careful not to screw too deep. Just deep enough to not stick out, and mud over. About a 1/16" deep or so. Or buy the bit for $5... https://www.lowes.com/pd/Hillman-2-...hBOdts_wvepSsE1v4ZhoCGdUQAvD_BwE&gclsrc=aw.ds