Glenn Fellman of the IAQA answers Air Quality Question about a Homeowners Basement Finishing Problem


<--Question is:
“I recently waterproofed and remodeled my basement due to water
seepage/damage. While the basement was gutted, there seemed to be no odor but
since the new carpet, drywall, etc. has been installed, there is now a stench
residing in my basement. Because I know that there is no water leakage, I
purchased a dehumidifier for the basement. Although the basement smells better,
the stench now fills my upper level. The weird thing about it is that my windows
are open, and of course, there is no heat/air running, so I am curious as to why
it is now smelling up the upper level. Any comments or suggestions would be
greatly appreciated."

Dawn McAfee
Louisville, Tenn.

A: “If there had
been a leak, there may be mold in the basement that is causing the odor,” said
Glenn Fellman, executive director of the Indoor Air Quality Association, in Rockville, MD. “Mold colonizes behind walls, under flooring and in other hidden
areas, he said. Mold may have been disturbed during the renovation, allowing it
to become airborne and dispersed throughout the home,” he said.

"Another possible source of odor may be the new materials used for waterproofing and remodeling, he said. Epoxy, glue and water-proofing products may emit odor-producing volatile organic compounds (VOCs). There may also be VOC emissions from new carpet and other furnishings, he said. A dehumidifier will only remove moisture, not odors.”

"You might want to try using a room air cleaner that incorporates a
carbon pre-filter and primary HEPA filter to reduce the odors in the short-term.
Long-term, you need to identify and eliminate the source of the odor," Fellman

“Because I know that there is no water leakage, I purchased a dehumidifier for the basement.”
The problem with this statement is he has utter trust in the waterproofing product/company that served him. While trust is good, protection is better. Knowing you’ve had leaks warrants the installation of wall protection as well as a drain system. Many people finish off with no wall protection and their leak situation changes. So behind walls that they can’t see behind resides and unsolved basement wall leak that they thought, “Could never happen.”

“so I am curious as to why it is now smelling up the upper level?”
This is because of a change in pressure in the home referred to as “Stack Effect.” What happens is that air flows from the basement up to the 1st floor as it warms up. This air now creates a void in the basement, which pulls air through the foundation walls from the soil and the outside to fill it. The air from the first floor and 2nd floors eventually moves through the walls and windows to the outside which continues the cycle and pulls the air from the basement all over again. Any smell that’s occurring in your basement will eventually occur in your first floor. If you want to test this, spill a small amount of bleach at the bottom of the steps in your basement and wait. You’ll eventually smell the bleach on your first floor because of the air movement in the home. (You don’t need to use bleach, but something smelly like Lysol or Febreze might work just as well)

I can’t find one point to disagree with Glenn Fellman on, well done!

It does bring up the point of epoxies and glues used in waterproofing a basement. If a smell is persisting more then a day or so, there’s something wrong. Contact your waterproofing company to verify.

I personally don’t suggest the use of anything that gives off VOCs, especially any sealants. Some vapor barriers require a bit of epoxy just at the top to seal off the system and secure it to the foundation, but the odors from that are mild and shouldn’t persist past the first 24 hours.

If you’re concerned about VOCs there are plenty of low to non-VOC finishing options out there. But be prepared to pay a little more for them. They’re worth it if you’re worried about your air quality; at least that’s how I feel. No VOC paint has come down drastically in price over the past few months and the chemistry leaves a perfect painted finished coat on your walls.

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