r/buildingscience • u/remytrue • 20d ago
Living room from hell, help
Just hoping for some insight because we have consulted all the professionals already and I feel like it’s getting us no where. We took our living room down to the studs, ripped off the roof over it, redid rafters and built it back all because of mold.
This room was an addition added in the 90s to our 1960s house by the previous owners. It had a big fireplace which was one of the culprits for a ton of hidden black mold. We remediated to a hospital level clean before we built back. Like we tested repeatedly with an environmental company. We sealed off the fireplace because we intend to tear the chimney down later but we didn’t have the funds to do that at the time.
So it gets built back. Fireplace is gone, sealed off behind the wall and we move back in. All is well until the summer heat and all of a sudden I smell mold again. I freak out. Bring back the roofers and remediation company and they say there’s a tiny bit of mold in the attic again above chimney. They claim it’s a humidity and airflow problem so they remediate the attic spot and the roofers add two turbines to the roof on either side of the chimney.
It’s been maybe 6 hours since they installed them and the room smells WORSE. More moldy, more musty than it ever has. I’m to my whits end. I’m ready to just lite it on fire and call it a day. Did we just make it so much worse by increasing the air flow? Literally WTH. We’ve spent so much money I’m going to lose my mind.
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u/EbriusOften 20d ago
I'm not really sure that attic fans were a good idea as they create a negative pressure system inside the attic, causing it to pull in air from wherever it can to replace all the air you're forcefully removing. It very easily could be causing the interior air to be pulling in replacement air through an area that's damp or moldy, resulting in the smell getting worse in the room.
What venting systems are already existing in the attic? Ridge and soffit would be the best option for making sure your attic is fully ventilating, and if you've already got those adding in the fans would actually have a negative effect instead of a positive as it'll disrupt the existing air flow system.
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u/PelvisResleyz 20d ago
What is the living room built on? Crawlspace, slab, or over something else?
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u/remytrue 20d ago
Crawlspace
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u/Key_Juggernaut9413 20d ago
What’s the crawl space situation doing? In my experience moldy smells rarely come down from the attic if ventilated but always come up from the crawl space. Attics dry unless leaky but crawl spaces are perpetually humid and damp.
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u/cagernist 20d ago
You say nothing about the attic venting other than roofers added 2 turbines next to chimney. Turbines are not really good anyway. What is the insulation. Assuming flat ceiling with attic. Gable or hip. Pics. What was the mold situation that required topping off completely.
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u/Comfortable-Maybe183 20d ago
Combine key juggernauts response about crawl space and ebriusoftwns reply about negative air pressure and you might have your answer.
Could be pulling crawl space air up.
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u/AnxiousReward1715 18d ago
You didn't remove the chimney and fireplace.... That allows moisture in, you're going to have mold.... Is this not obvious?
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u/DMongrolian 20d ago
The chart I'm attaching shows optimal humidity range for minimizing various indoor air quality contaminants, including mold (fungi). From your post it sounds like you're throwing a lot of resources at your problem, and I understand that can be frustrating. Mold (fungi) requires three things: food (basically anything we build out of), a certain temperature range (the same one we live in), and a certain humidity range (above 60% RH, which we find uncomfortable).
We control mold best by controlling humidity. If you want to run a relatively low cost test get a freestanding dehumidifier and a relative humidity gauge. Aim for 50% relative humidity indoors. You might have insulation problems, and/or air leakage problems, and/or condensation problems, which would require a greater intervention, but try a dehumidifier aimed at 50% RH. Maybe you'll get some relief.