Possible Mold Problem and Solution?
Hi All, We live in the first floor of a corner Brownstone in Brooklyn. We also have a finished basement which is 100% below grade. We have spent considerable time and money to turn the basement space into a home theater and office. There was initially a wooden subfloor covered with engineered wood in the…
Hi All,
We live in the first floor of a corner Brownstone in Brooklyn. We also have a finished basement which is 100% below grade. We have spent considerable time and money to turn the basement space into a home theater and office.
There was initially a wooden subfloor covered with engineered wood in the basement. We had this ripped out after the basement flooded a few times and a musty smell suggested, and later confirmed, the presence of mold. This floor was replaced by a new concrete slab with a beautiful, glossy painted and sealed finish.
I have taken some measures over the years to prevent future floods (serviced an ancient back flow trap that was allowing sewer water to come out of the basement toilet and shower) and the basement hasn’t flooded for a few years. A humidifier is constantly set for 60% humidity.
But the musty smell has persisted and the most likely source is a wall in the basement.
The suspect wall is dry wall and studs that covers a foundation wall made up of Manhattan Schist. There is no insulation in the wall and the foundation wall is covered with efflorescence. The wall is 24′ and runs along a side street so it is very susceptible to run-off and ground moisture.
Four or five years ago a leak came out from under the drywall. I removed the drywall in that area, sealed the leaking portion of the wall with Quikrete Hydraulic Water-Stop cement and Drylok paint and repaired the drywall. But I suspect the wall is leaking small amounts water fairly regularly.
I’m concerned about mold and mildew, especially with kids in the house. I poked some exploratory holes (12″ x 6″) in the drywall and found no visual signs of mold. The bottom of the cavity is filled with about 1″ of dirt that has crumbled from the wall and it is dry to the touch.
I see two plans of attack…
1. Rip out all of the drywall, clean and Drylok the wall and leave it exposed so that it can be easily maintained as the moisture and efflorescence inevitably reappears.
2. An architect suggested the solution of putting vent holes (12″ x “6 covered with return vents) along the top and bottom of the wall to vent the space. But will this just create more airflow for mold and mildew spores to spread to the rest of the house? Will warm air flowing against the colder rocks create more moisture leading to more mold and mildew?
I would appreciate any thoughts.
Thanks,
Mike
jock, could you post the name of the company that does the drill/clay solution? What is the cost relative to the trench drain solution?
I was posting too darn late! You can waterproof the exterior of the foundation walls from the interior. There are companies that will drill though every so often and pump clay waterproofing solution. I used it once on one of my projects that had an underground stream causing problems. It worked great. Another way is to install a trench drain at the base of the wall, any water coming in goes there and then gets pumped to the sewer.
Unfortunately most brownstone basements will suffer to varying degrees, some sort of moisture problem.
I agree with your approach and both seem sound. Keeping the problem walls in plain sight helps you deal with any problems immediately. As for venting, maybe a dedicated hrv (heat recovery ventilation) system in the basement will help alleviate the problem. This system basically exhausts stale air at a balanced rate while at the same time brings in fresh air. Depending on your basement, the duct work may be more trouble than its worth.
Short of re-waterproofing your basement/foundation walls from the exterior, the best you can do is source control the mold as much as possible. I wish you luck.
jock
it is 100% below grade
Sealing the interior of a wall is not going to work long term. If the wall in question is 100% above grade, where is the moisture coming from? What does the exterior of the wall look like?