# Split face block mold problem.



## Midwest BuildIT (Mar 16, 2006)

One of the buildings my client owns has a mold problem. It appears so far to only be on the outside. Roof is not leaking at all. And the metal panel siding is dry as is the top of the block wall inside.

I don't see any flashing or weeping holes, I also don't believe the block is sealed. There are offices in the front but most of it is open warehouse. no signs of water on the inside except near the back where water is getting in through some other places that i will take care of first.

After that i have to figure out the mold problem. I know i have to clean the mold and pressure wash the building. Now comes the hard part..

How do i get the block dried out so i can seal it and not just seal the water in ? Don't want to end up pushing all the water into the wall. Should there be some sort of weeping holes in this wall ? And will sealing it really solve the issue ?


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## griz (Nov 26, 2009)

You have a serious moisture problem...

also get a mold remediation guy to deal with the mold...

Do you have access to the as builts? 

Can you cut inspection holes from the inside to see what is going on?


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## Midwest BuildIT (Mar 16, 2006)

griz said:


> You have a serious moisture problem...
> 
> No, its just a little mold. lol
> 
> ...


I can do anything, lol, but i dont thing the guys in that end unit will like it very much. lol. they have a lot of workstations along that wall.


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## griz (Nov 26, 2009)

Can you get original plans from the Bldg. Dept?

Could you get a camera through a small hole in a base board & go from there?

Some where along the line you will have to disrupt someone to find out what is going on inside the wall.

A little mold is sorta like being a little pregnant....:thumbup::laughing::laughing:


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## Midwest BuildIT (Mar 16, 2006)

Also on that end unit where those pics were taken is where its the worst, the rest of the building is not bad. that is also the north wall.

That unit is also fully air conditioned. Dont know if that makes a difference.

We have also had an above avg hot and dry summer here. I worked at this building a little last year and it wasn't this bad.


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## griz (Nov 26, 2009)

Whether anyone likes it or not....

time for some exploratory surgery....

You have high humidity there?


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## Midwest BuildIT (Mar 16, 2006)

griz said:


> Can you get original plans from the Bldg. Dept?
> 
> Could you get a camera through a small hole in a base board & go from there?
> 
> ...


80% of the inside of that wall is just the back side of the block. its painted and no signs of mold. though i didnt get a great look as they were having a corporate meeting. no signs of mold on the inside of the unit next to it either. no interior walls.


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## griz (Nov 26, 2009)

Midwest BuildIT said:


> 80% of the inside of that wall is just the back side of the block. its painted and no signs of mold. though i didnt get a great look as they were having a corporate meeting. no signs of mold on the inside of the unit next to it either. no interior walls.



No insulation or vapor barrier?


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## stacker (Jan 31, 2006)

we have alot of that around here with split face block.i really dont know what causes it.i noticed the other day,a retaining wall i built 16 years ago has this mold on the outside of the block.i think its more moisture getting trapped in the rough face of the block more than moisture penerating from the inside out.


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## Diamond D. (Nov 12, 2009)

stacker said:


> we have alot of that around here with split face block.i really dont know what causes it.i noticed the other day,a retaining wall i built 16 years ago has this mold on the outside of the block.i think its more moisture getting trapped in the rough face of the block more than moisture penerating from the inside out.


I agree, its like the mold that clings to roofing granules.

I'm tellin' ya, forget about the aliens, mold is about to take over the world.

D.


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## parkers5150 (Dec 5, 2008)

north facing is the culprit


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## Midwest BuildIT (Mar 16, 2006)

Take a look at that first pic. That's a west wall. After that last post it got me to thinking that the downspout blocks the sun from that one spot on the wall probably all day. Might explain why the wall is so bad right there.


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## concretemasonry (Dec 1, 2006)

I would take a long and hard look at details and flashing where the wrinkled tin siding sits on the block wall. It appears that there is a lot of wall area and no proper drainage method down to get if away, so it gets into the cores.

It looks like a "off the shelf" metal building with concrete masonry on the lower areas to provide and a hard/durable and smooth interior finish. You may also find a pattern of the wet wall areas that are close to the joints in the "flashing" where the block and wrinkled tin meet.

Also, look at the flashing details at the roof line to make sure there is not a path for wind-driven rain to be forced upward and into the building and eventually run down to the block wall. - A very coomon problem with that type of building.


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## parkers5150 (Dec 5, 2008)

bleach solution in a hudson sprayer....power wash.... re apply bleach:thumbsup:


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## fjn (Aug 17, 2011)

*mold*



parkers5150 said:


> bleach solution in a hudson sprayer....power wash.... re apply bleach:thumbsup:


 That may remove it what will prevent it from coming back?



 Read this,it may provide some insight.


http://www.maconline.org/tech/mater...ncretemasonry/singlewytheconcretemasonry.html


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## dom-mas (Nov 26, 2011)

I'm with everyone else here. The flashing between the tin and the block is opposite of what it should be. Instead of water running down the steel and getting thrown away from the building it can follow the flashing onto the block. Couple that with N facing or blocked from the sun and a rough surface that holds moisture and you have a damp area for mould to grow


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## Midwest BuildIT (Mar 16, 2006)

So do we all agree that cleaning and sealing the block would prevent the mold ? Sealing it would keep it from absorbing the water, then slowly releasing it, and growing the mold.

I see how adding a piece of flashing to kick the water out away from the wall would help, but i dont think its mandatory. Since there are multiple owners, anything exterior has to be done to the whole building. My customer owns the end units with the long side walls with the most problems, the other are in the middle with little problems. I doubt they would go for that. They are already agreeing with the cleaning and sealing as long as it solves the problem.

Like i said before, everything from the bottom of the steel flashing up is dry with no signs of water. I believe this is just a surface problem.


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## Timo (Nov 22, 2006)

Midwest BuildIT said:


> So do we all agree that cleaning and sealing the block would prevent the mold ? Sealing it would keep it from absorbing the water, then slowly releasing it, and growing the mold.
> 
> I see how adding a piece of flashing to kick the water out away from the wall would help, but i dont think its mandatory. Since there are multiple owners, anything exterior has to be done to the whole building. My customer owns the end units with the long side walls with the most problems, the other are in the middle with little problems. I doubt they would go for that. They are already agreeing with the cleaning and sealing as long as it solves the problem.
> 
> Like i said before, everything from the bottom of the steel flashing up is dry with no signs of water. I believe this is just a surface problem.


(In this case). Cleaning doesn't fix anything, it just temporarily masks the symptoms of poor construction details. 

Sealing does not make up for lack of poor construction details, it just extends the cleaning intervals.

Some split face products are treated with sealer at the time of manufacture. Water can and will get behind that sealer and then your task is to break through the sealer to get at the growth behind. Sometimes easier said than done.

The growth at the downspout - is there a break in the flashing above feeding bulk water to that location?


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## parkers5150 (Dec 5, 2008)

the growth at the down spout is due to the shadow cast by the downspout itself


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## dakzaag (Jan 6, 2009)

If you are not seeing any indication of moisture on the inside of the building then this is mostly an exterior problem. The flashing looks like a typical "rat guard" on metal pole buildings all around the midwest. It is fine for this application, but do a complete investigation of the interior when you have full access to confirm there are no moisture issues inside.

The discoloration looks like a typical biological growth due to high moisture content. Midwest humidty can match levels found near the coast albeit without the added salt content. The downspout is a clear indication that the sun is drying out and killing a majority of the growth and mostly the north side of the building needs treatment. 

Pressure washing or just scrubbing with a hose and some simple green will remove 60-70% of the growth. Unfortunately it will regrow rapidly because it has established itself in the pores of the block. 

A bleach solution will help kill some of the activity, but it is a crude method and you can cause more problems with bleach spots on the tin/block and surrounding surfaces. 

I use a commercial product that does a very effective job of removing the biological growth, brightening the masonry and killing the organism that is growing in the pores. PM if you would like more detail.


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