Need help water problem in the wall
 

Hi all, this is my first post and I need help

My church have this minor problem where there is an exterior furring wall (sheetrock furred over exterior CMU wall) which showing water mark…
So I open it up and find that some of the metal furring is corroded and some of the sheetrock have some minor mold. I also notice that the corrosion on the metal furring is started from the metal furring fastener to the CMU, that make the drywall wet.

Can you kindly suggest what kind of thing I need to do to fix this?
What is the thing that can cause this?
Do we need to change metal furring?
What should we do to prevent this from happening again?

Thank you

It does appear that their is a moisture problem and that it is coming from the concrete block. You should replace the metal channel but you need to first determine why the interior side of the block has moisture. Inspect the exterior and give particular attention to the roof above the wall. If you post a couple of photos of the exterior wall and roof you will likely receive some good comments from those that visit this site.

Your location will also help----that corrosion and stained blocks could also be condensation---I don't see any insulation---does that block get cold?

Is the other side of the wall the outside of the building? If so is it painted or covered by siding? It looks like there are dark and light stains both vertical and horizontal that may indicate moisture from inside the blocks. Maybe some pictures showing more of the wall.

Their is a moisture problem and it is coming from the concrete block.

First determine why the interior side of the block has moisture. Post pics of the exterior wall and roof also so that we can see if its affected also...

I also see water stains from water running down the inside surface otf the wall. Possibly from a leak above at some time or other.

Putting wrinkled tin studs directly against a concrete wall is never good, just as wood should be pressure treated or a gap/barrier between. Galvanized tin studs are not immune because the galvanizing gets scratched, allowing corrosion and the screws strip off the galvanizing as they are installed and provide a path inward for corrosion. - Not a good detail or plan.

Dick

Wall
 

Thank you for all your prompt reply... I will take more pictures for the outside wall and roof today..
Fyi the locations of this room is at the first floor. And yes the concrete block is cold and no insulation.

More picture
 

Here are the pictures... any help is great
please see the pdf attachment.. thank you

https://docs.google.com/open?id=0B6S...WJHdkUyQXdBX3M

1) There are two "layers" to that wall - the exterior cladding, and the interior CMU wall. Do you know if it is a composite wall (ie grouted between the interior and exterior "walls") or a cavity wall (there is a gap between them)?

2) RILEM / MAT test the wall at the exterior.

3) Check for water intrusion at the wall-mounted light fixture.

4) Was there a vapor retarder (plastic sheet) in the wall where you removed the drywall.? If so where was it located (ex: against the CMUs, against the drywall, etc.)

@ Michael
1. there is the gap between the CMU wall and the sheetrock, metal channel was used
2. MAT test - can you elaborate, what that means?
3. Will check on the light fixtures but, it seem is too high
4.No there was no vapor barrier what so ever .. which I think I need to put it in and maybe insulation too.

Any other inputs guys?

I think driving rain occasionally causes some seepage ----that coupled with condensation on the block when the weather is just right has caused that mold and corrosion----

Just a guess---A layer of foam board properly sealed would be my suggestion----

One of the masons or a commercial builder might have a better idea of the cause----let's see---Mike----

You may want to check to see if the conduit from the AC unit is leaking. I guess it would depend on how big the hole is that it goes through, or if it is even sealed.

Thanks Mike
@ Duckweather.. the AC conduit is fine.. that was my first check

I did not think there was an exterior "cladding" the Michael saw.

Many churches and especially attached educational/recreational attachments have single wythe CMU walls that are difficult to waterproof, but not as difficult as vinyl ot similar cladding that is hung on a wall?

While you are concerned with vapor barriers and foam on the interior, looking at the exterior materials/coatings and details that are exposed to the wind and conditions.

Dick

We know for certain (from the pictures) that the interior and exterior of the wall are made of different masonry materials, I was using the term "cladding" loosely.

If that's a grouted composite wall it "should" be nearly impervious to moisture penetration through the wall itself. If it's a cavity wall, and the exterior is relatively permeable, there are several mechanisms (ex: mortar bridging) that could be conducting water to the exterior. I don't recognize the exterior material, however it looks like it might be a cast concrete product, and if the mortar between the precast units is absorbent and unsealed.... well... you have a likely source of water intrusion right there, if it's a cavity wall.