Learn from Me. Don't Let this Happen to YOU!!

[Jorge P.]

I'll start off  by saying... I actually LOVE when things like these happen to me because it gives me an opportunity to learn & figure out  the solution to a problem thats common in homes in my market. Now that I know how to solve this issue, Im able to buy properties some may pass on when they encounter it. 

Plot: Plot refers to the sequence of events inside a story which affect other events through the principle of cause and effect

I had just finished remodeling the last apt in my latest multifamily rental property. The apt & property were officially tenant ready (so I thought) and I decided to take a 2 week vacation to compansate myself for the work well done.  

I leave. I come back & this is what I find when I walk into the apt: (warning! Scary pictures below)

I had a mixed of emotions run through my head, when I saw mold growing on the brand new doors I had installed.  (Shocked, Scared, Upset, frustrated, confused , Sad (lol) & Curious.)

My last emotion is one I consciously choose when I encounter a problem, in order to get into "Action mode". I asked myself the question:

WHY was MOLD growing in my brand NEW Rental!? WHY God! WHY!!? -  I needed to understand it. So, I got on google & started researching .  The answer to my question. Humidity.

WHAT I LEARNED ABOUT MOLD: 

Mold will start to grow in any indoor environment where the humidity level is at or above 50% for an extended amount of time. 

With that said, I needed to find out what was the Humidity level in the apt. I bought a Hygrometer, which revealed the humidity level in my apt to be 71%!.  (Mold haven)

My goal then was to stop the mold from growing, spreading & prevent it from growing again. 

MY SOLUTION: 

1.Kill/remove the current mold by using a mold remover spray , letting it sit for 2 hrs then scrubbing it off. 

2. Bring the humidity level below 50% to stop & prevent mold from growing. I bought 3 dehumidifiers and had them run. After 20 min. the humidity level dropped to 65% 😁. These humidifier would turn off when it reaches the desired humidity & on when humidity levels increase. (I set it to 40%).

As long as I  keep the humidity level below 50%, the mold won't come back.  The apt is currently being retouched & should be ready to rent in 3 weeks time.  The real problem however was not the mold. Ask me about the real problem and how I solved it in 2 weeks 😁

Sorry for the long post, I hope you found it informative. 

[Jim K.]

@Jorge P.

I apologize in advance for how technical this response is, but I think it's worth your while to read it.

The solution you're following is, bar none, accepted in renovation circles as the most foolproof yet expensive way to fix a basement HUMIDITY problem.

However, it is highly unusual for a professionally-constructed house built any time in the last hundred years to be so situated as to have a truly severe humidity problem and little or no outright flooding. It can happen due to erosion or significant changes to the land around the property. But external foundation sheathing and an external footer drain is typically a last-resort scenario reserved for extreme cases.

I'm not there. Your contractor is. That goes without saying. But again, it's a truly extreme situation that can't be settled with an interior perimeter French drain connected to a sump pump, as well as other basic measures. You regrade the land around the external perimeter of the house or in extreme cases add a sloped 36-inch concrete perimeter, paint the interior bare walls of the basement with Drylok to mitigate at least SOME of the casual problems,  and run large dehumidifiers down there.

Of course, in order to do this, you've got to demo the whole interior of the finished basement to put in interior French drains. I suspect at least one or two of your fifteen contractors explained this to you. Because leaving the interior as is and working solely on the exterior to fix the problem presents another problem.

While mold is related to humidity in that humidity gives it a hospitable environment to grow, mold can happen anywhere, just as @Matt Shields has pointed out. A lot of basements finished well into the 1990s are very much mold farms behind the walls. The idea in cheaply finishing basements to turn utility space into living space used to be that as long as the finished separated the exterior conditions of the below-grade concrete walls from the internal environment of the basement, typically by running a 4-mil plastic sheet along the concrete walls, the finisher didn't have to worry about using normal above-grade building materials to finish the basement.

This turned out to be false, as was proven out over time. 

Good basement finishing jobs nowadays typically rely on the sump pump and interior French drain solution I mentioned earlier, but just as much on specialized insulation and building materials specifically designed for high-humidity, mold-friendly environments: steel studs, purple drywall, polyisocyanurate foam board insulation sealed with seam tape and spray foam and silicone sealant, a raised floor or a tile floor laid over a wateproofing membrane, and PVC trim.

Your apartment here is obviously a basement apartment, judging from the window placements. There's also very little outright flooding, judging from the undamaged condition of the baseboard heater in the background.  The apartment appears to have been very nicely finished, but I don't know when. If much of the basic basement finishing happened way back when, you probably have, behind the walls, plastic sheeting stretched across the concrete block walls, fiberglass batts stuffed into the rim joist cavities, organic fiberboard insulation lining the plastic, and regular drywall with untreated 2x2's serving as studs, nailed into the concrete masonry block walls with a powder-actuated nailer. These are the hallmarks of a mold-friendly basement finishing job.

So the mold's going to hang tough back there, Jorge, waiting for any opportunity to come out and play again. If you continue to have problems with the mold despite your expensive solution, your only chance of eradicating the problem permanently is to strip that apartment back to bare concrete, bleach the everlasting blankety-blank out of the rafters overhead, and refinish the entire place using the materials I've mentioned.

I hope your solution ends the mold problem, as it WILL end the excessive humidity problem. But I'd watch like a hawk for mold issues to start coming back, and I wouldn't blame them on my tenants.