Help with VOCs from strong basement outgassing (Kilz)

T Bone
last month

So I bought a flipped house 1 month ago. When I toured the house there was a strong chemical / paint odor, but my agent said that most flipped houses smell this way as it was just renovated. Fine, that makes sense.

I moved in and tried to air it out, but the very strong chemical odor has persisted particularly in the basement. House is not large, 1100 sq ft ranch. I can get the smell essentially gone on the main level with fans / open windows, but as soon as I close off the windows and turn on AC or heat, the smell is cycled up from the basement and returns. I've been running fans in the basement w/ open windows every day, smell returns within hours once things are shut off.

The smell is so strong it permeates all clothing and fabric. I trade my 7-year old with her mother every other week, and she has complained that all her clothes and stuffed animals reek of the odor - and it cannot be rid even after washing the stuffed animals. Bought 2 air purifiers based on top reviews on Consumer Reports, not clear they help (though they might some).

So I bought a VOC sensor that also tracks Temp, Humidity, CO2, and 2.5um particles. It is a TVOC sensor (total VOC), so it does not differentiate individual components. I extensively tested the sensor after purchasing it. I left it sitting for one day in same conditions (fresh air from windows/fans), then brought in old bottle of motor oil and opened it right in front of the sensor. It responded within minutes going up on VOC reading by 50%. Once I removed the oil bottle the VOC reading went back down to previous level. The readings also seem to make sense - they track with (but lag behind) temperature, and it is fairly well established that higher temperature causes more VOC outgassing.

The VOCs respond generally as you would expect - when the windows are open and fans are going they drop like a rock. When everything is shut down w/ AC or heat they go up, but they go up much more with heat. With the heater on the range for VOCs is 400-500 ppb, which is absolutely *unacceptable*. World Health Organization standard is less than 100 ppb TVOC for indoor air. Even with fans and windows it rarely falls below 100 ppb. CA standard is less than 20 ppb. European standard is very low as well.

I have a 7-year-old in here half the time and must get the levels *down*. Had the flipper's contracting worker in here to fix something (not the company owner but one of the guys that actually did the work to flip my actual home) and I took him into the basement and asked him what he thinks the smell is. Right away he said its the Kilz oil primer used to seal the basement walls, has a very strong odor that lasts a while he said. This guy does this work all the time, he probably knows.

How can I get the VOCs gone ASAP? Please help if you can.

Thank you!

Comments (6)

  • Faron79
    last month
    last modified: last month

    Yes, that primer has quite the odor!!

    Actually, VOC's & ODORS have ZIP to do with the other! Some low/no-voc Waterborne paints smell kinda BAD!

    There's nothing to do but wait. Provide as much "Air-exchanging" as you can tho'. Oil-base products don't "dry out" in the traditional sense. They CURE be reacting with Oxygen molecules in the air.

    The more air you can "exchange" per day, the better. Put some fans in windows blowing OUT. Put cardboard or something around them. Have other fans pulling air IN.

    Good Luck!

  • live_wire_oak
    last month
    last modified: last month

    Kilz dries within 29 minutes and stops smelling within 48 hours. You’ve got other issues. Vinyl floors? Mold under the Kilz? Carpet? Plumbing issues? Something.

  • Jennifer Hogan
    last month


    Hire an indoor air quality consultant.

    Based on findings -

    Find out if mitigation is covered by your home owners insurance

    Discuss findings with seller - ask to have them assist with cost of mitigation.

  • T Bone
    Original Author
    last month
    last modified: last month

    Ok, thank you to everyone! I am doing the blowing air out of basement suggestions with cardboard helping to ensure air blows out.

    There is no carpeting in the home. There is some kind of laminate used in the kitchen, and its new, I'll try to figure out what it is. I asked a neighbor and they did say there was mold in the house (they had been in there before it was sold to help the owner), but it isn't clear where. Though I'm unsure mold would cause VOCs. I suspect that's why the Kilz was used in the first place - to kill the mold? There is no obvious mold on the boards/vents in the basement - nor was it found in the inspection.

    In terms of air quality mitigation, sure I'll try that, thank you. I've never heard of insurance covering that, but I'll ask my agent. I've talked to the seller about this already, and he said he'd bring in ozone to treat it, but I'd have to remove everything from the home. But does ozone actually stop VOCs? I thought that just stops odors, but that's not primarily what I'm worried about.

  • opaone
    last month

    I agree w/ @live_wire_oak. My experience with Kilz is similar and no or only very limited odor after 2 or 3 days. I'd look for something else. In the meantime use exhaust fans in windows, ideally in the affected area or as close as possible in a way that pulls fresher air through the offending area.

  • mmmm12COzone5
    last month
    last modified: last month

    There is a problem that has been going on for at least 10 years with some paints that don't cure properly and stink forever. We repainted our guest bathroom in 2013. The paint dried but stunk like chemicals. We waited a whole year and the smell did not go away. I found some very extensive forum links from people who had the same problem. The problem seemed to be across paint brands. Just did a search on it and found this forum with posts from 2019/2020 so it is still going on.


    The fix that most resulted to on the forum I was following in 2013 was to replace the drywall. Which is what we eventually ended up doing in 2015. Tore the whole bathroom out (tile also due to there being drywall above the tile line) and replaced every painted surface with new drywall. Smell gone!

    Many people tried encapsulating the smell with various products, baking it out, ozone machines etc. We tried baking and ozone with no luck. From the many posters it seemed only drywall tear out and replacement worked so that is what we did. I was very nervous to paint the new drywall and every paint brand you could think of was on the thread as having caused problems.

    Zero VOC and low VOC paints seemed to be the common thread of people that had problems and it was across all brands. I suspected improper mixing of chemicals from China that were common to all paints. As a result I chose a paint made in the USA called ECOS paint. I spoke to them on the phone and they said they did all their own manufacturing and had not had the problem with the odor that doesn't go away.


    Edit: Just found this thread that sounds like your situation with Kilz.


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