Air leak and moisture intrusion

Hello, folks
I went for an inspection today of a 10 story building that has moisture issues leading to extensive Mold everywhere. In common corridors of different floors, and in at least 20 apartments out of a total 60.
Apparently, not plumbing issues /leak found, as it has been checked thoroughly by a licensed plumber. The issues are showing in middle floors so not chance of roof leak or GWT in ground floors. From my initial evaluation, it looks like air leakage from somewhere (properly around windows) that causes a condensation when it hits the cold rooms and AC ducts in the ceiling.
We’ll go again to try to qualify our assumption using thermal imaging to try to find air leak spots around openings/windows etc.
Any experience on how to create negative pressure inside the apartments given the fact the we do not have blower door test kit.
Other than turning on the exhaust fan in bathroom and kitchen, do you have any other tricks to create the pressure difference to be able to see it with the IT camera?
P.S water droplets seen Ain floor and walls, wet ceiling and Mold, etc
Even a ceramic wall in the common area corridor is very wet at the surface (photo attached)
Any suggestions would be appreciated

That building either has a system issue or it wasn’t designed properly. No way should there be that much moisture in the building. At a minimum, the corridors and common areas should have a neutral air system.

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I would agree, most likely an HVAC issue

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Thanks, Daren. Agree. Problem is that I’m supposed to do a defect analysis and know the fault and the rectification. They have been in this for two years, hired a consultant engineer, HVAC contractors, etc. and no one gave them an answer on the why it happens and how to correct. They spent 10M USD with the contractor to build it and the contractor is willing to take the liability and do the rectification needed, as long as they tell them what needs to be done to correct the problem. The landlord is loosing most of the tenants because of this issue, especially the Mold

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As I replied, what could it be and how to correct. That is the mystery

Fault: too much humidity in the building
Rectification: air balance and energy balance study for the building, followed by equipment repairs/modifications.

Solving the problem does not fall within the scope of a commercial or home inspection.


Has any drywall been removed at the wet/moldy areas?

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That’s a tough one! We all know that mold strives when it has a food source, water source and controlled environment. What’s the humidity levels?
You can turn the HVAC system into a Heat Pump system, run it in Dry mode and the HVAC system can act as a high efficiency dehumidification system.

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Given the scope of your inspection, you should be able to justify the purchase or rental of a blower door.

And, a series of recording humidity meters


Humidity is the leading cause of mold proliferation.
While I inspect apartment buildings/condominiums I am monitoring RH, relative humidity constantly. As for materials exhibiting signs of microbial growth, I take drywall and material measurements and photo all measurements for prosperity. Reports choreograph the process with any visual suspect conditions, and measurement examples.
Observation: Suspect: Microbial growth. Prolific in areas. Plainly/Clearly Visible on various materials on floors/corridors walls and ceiling throughout the building.
Recommend: 1: A licensed mold and remediation consultant/contractor. 2: A licensed ventilation contractor 3: A licensed commercial envelope caulking/sealing contractor.
Follow any referrals offered.

*Note: I use the narrative; SUSPECT Microbial growth as not to box myself in.

Here are 2 photos. I use a hygrometer. I have 2. Fluke hygrometer was $1,000.00 with calibration.

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I do not think that we all know this. Mold does not need a “controlled environment” to *thrive. Where did you learn this?
I would say that an uncontrolled environment may be the problem in may cases where mold is thriving.

Please explain your post, Alfonso.

Christopher, this is a concrete block wall structure. No dry wall other that the fall ceiling in kitchen and bathrooms

No measured yet as we did not start the actual inspection. I believe it will be in the 70’s

Yes we rented a blower door and we’ll be running it, together with smoke test

Temperature in AC might be too cold? Might have to insulate the duct work.

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In fact it is freezing cold. At least in corridors. However, the issue is happening in multiple units occupied by different tenants so you would think that not all of them will be setting the temp too cold like this

Be careful. You’ll likely end up pulling mold and other contaminants into the living area. Any residents that are bothered by mold could experience issues.

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I inspect apartments.
The concrete block buildings have the most mold problems.
By far.

There is so many potential causes for this. You may want to start from measuring the relative humidity or verifying the ventilation systems
My first guess heating/ventilation issue. Every building should be equipped with a ventilation system.