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Community and Q&A

Living above the boiler room

coliana | Posted in General Questions on

Dear Green Building Advisor,

I am wondering if you might be able to help us come up with a solution to living above the building’s boiler. We have been struggling with some exhaust gases escaping into our apartment through the floor, despite the fact that everyone is telling us it is not possible. The floor is made of concrete slabs, so our guess is that the gases are escaping through the joints between the concrete slabs. We have purifiers in the apartment, but they are not enough.

Someone suggested insulating with special insulation paint that would keep the gases from escaping into our apartment. Our son has just been diagnosed with asthma, so we want to act as quickly as possible. Is there any solution beside moving out?

Thank you in advance for your help!

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  1. Siffe | | #1

    Concrete is gas-permeable - think radon. I would ask the city/town Planning Dep't for an inspection and tests. I wouldn't even think about trying to seal if it continues.

  2. GBA Editor
    Martin Holladay | | #2

    Concrete is not gas-permeable. Concrete is an air barrier. When radon enters a basement, it is entering through the sump, or the crack at the perimeter of the slab, or at plumbing penetrations.

  3. GBA Editor
    Martin Holladay | | #3

    If you live in the U.S., and you are renting your apartment, your landlord is legally required to provide a safe environment. If there is evidence that flue gases are entering your apartment, conditions are unsafe. You should contact your landlord. If your landlord is unresponsive, you should contact a lawyer or a tenants' rights organization.

    Paint won't help.

    If your building has an atmospherically vented boiler, a technician needs to verify (a) that the boiler has an appropriate venting system (chimney), and (b) that the vent is not blocked or restricted, and (c) that the boiler room has a source of outdoor combustion air to supply the boiler.

    If no other remedy works, it might be possible to pressurize your apartment with a supply ventilation fan that introduces fresh outdoor air into your apartment. This would reduce the chance that noxious fumes could enter your apartment. But it's not the best solution.

  4. coliana | | #4

    Hi Martin,
    We live in a condo. The chimney was just cleaned, and we have been getting a lot less exhaust since then, but there is still some. (I am extremely sensitive, I am always the first to smell gas leaks, etc, which has also made me the canary for the boiler room leaks over and over again). The boiler room windows are slightly open to supply air. Two years ago, my husband used some kind of foam along the seams of the concrete slabs on the ceiling of the boiler room, and I could smell the foam in our apartment, but after a couple of days the fumes were less noticeable, so we concluded that the insulation foam helped. I am not sure if it has become porous from the heat or what, but last spring we could notice the fumes again. Then the chimney was cleaned and things were better in the fall, but now with the really cold weather, we are sensing some again.

    We live in Chicago.
    Thank you, all,

  5. coliana | | #5

    Oh, yes, and the ceiling of the boiler room is completely covered with soot. We just noticed that in the summer. When it gets bad in our apartment, it is a sooty kind of smell.

  6. kevin_in_denver | | #6

    Here's an inexpensive digital CO monitor that can also detect methane.|1&pl=1&currentURL=%3FNs%3Dp_product_qty_sales_dollar%7C1&facetInfo=

    If you are getting any CO leakage into your unit, it can tell you exactly how much, and if remediation has improved it.

  7. user-1135248 | | #7

    Wow, I would have landed on the local building inspector's phone
    *long* since. Your fumes being "less noticeable" is completely
    unacceptable; you should not have *any*. You clearly have a
    heating plant that's unsafe and unfit to be running in a
    habitable building, and it needs to be repaired/replaced as
    soon as possible or the building should have its certificate
    of occupancy summarily yanked for *all* of its residents.

    Get official/legal help on this NOW.


  8. davidmeiland | | #8

    I agree with Hobbit. Soot all over the ceiling of the boiler room sounds like a huge issue.

    If you're inclined, I'd like to see a few photos of the building exterior and a few of the boiler room, including the equipment in it.

  9. coliana | | #9

    Thanks for the offer. We will take pictures tomorrow and post them.

  10. davidmeiland | | #10

    I used the word "few" but I actually mean "a lot". From the exterior please show the overall building, the boiler room, your apartment, the roof, any mechanicals, etc. Inside, please show all parts of the heating system and other details of the boiler room.

  11. angelina1 | | #11

    I apologize for the delay. I had forgotten my password and was not able to log on to my account. Here are some pictures. The heating is hot water floor heating with thermostat controls in the individual units. I am not sure if this info is necessary, but just in case.

  12. angelina1 | | #12

    uh, i did not realize the pictures will come out all connected like that. i have more

  13. angelina1 | | #13


  14. angelina1 | | #14

    i never figured out what this is but it spins all the time

  15. angelina1 | | #15

    water heater

  16. angelina1 | | #16

    heated water pipe, i think!

  17. angelina1 | | #17

    compressor, controls the air pressure for the individual thermostats in the apartments

  18. angelina1 | | #18


  19. angelina1 | | #19

    back of boiler

  20. davidmeiland | | #20

    Wow, there's a lot of equipment in that room. This is somewhat outside of my expertise, but it looks like an older system with atmospheric draft equipment, and if so, there should be plenty of combustion air available from outside for that equipment. I think that a very qualified HVAC technician should determine whether there are issues such as inadequate combustion air, poor combustion, carbon monoxide, etc. An energy auditor or blower door technician should be hired to find all air leaks between living spaces and this mechanical space, and advise on the ways to seal them. What I see being done in one photo may be part of the issue, but there may be more.

    Another approach is to simply replace all of the boilers with one or more sealed combustion appliances. The building owner might recoup their investment in reduced fuel and maintenance costs, and the whole thing would be a lot more healthy for the building occupants.

  21. coliana | | #21

    Once again I had trouble with my log in, sorry. Thanks for the ideas, we will talk to the management company. Can I ask what you think about the soot on the ceiling? In an earlier post you said it is a problem. Any more information will be very helpful, since this is the only concrete evidence we have that the burning is not clean. There is a CO and a Natural Gas detector in the room, and neither of them have registered anything, but we continue to experience a sensation of burning in the throat and nose upstairs.

    Thank you again!

  22. kevin_in_denver | | #22

    An old building like this probably had a coal-fired boiler until being converted to natural gas in the 40's.
    I'm 90% sure that the soot is from that era. Gas rarely causes soot, even if the flame is maladjusted.

  23. coliana | | #23

    Actually, the building was built in the 1950s (54, 55, something like that), and, as far as I know, this is the original boiler. I will ask, but I think it has always been with gas. Does this matter?
    Thanks again!

  24. davidmeiland | | #24

    Angelina, not sure about the soot and not sure about the gas causing irritation in your living space, but I think you need a specialist out there to solve this, or maybe more than one, a combination heating technician/energy auditor/home inspector. My recommendation is that you contact this guy:

  25. davidmeiland | | #25

    Added question from OP

  26. davidmeiland | | #26

    I would still be concerned about air leakage paths between the boiler room and living space. Are they going to look at that also?

  27. coliana | | #27

    The air quality test in our apartment is in order to convince them that there is leakage. On the one hand they say they believe us that there is leakage (because who and why would make up something like that), but on the other hand they want tangible proof. Then they will draft a plan for insulation.

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