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Community and Q&A

Something in my house is irritating me and others

Helpmewithmyhouse | Posted in General Questions on


Climate zone 7, Prairie

I’m concerned about the indoor air quality in my old house.  My nasal passages etc are irritated every time I’m in the house.  Some visitor’s noses start running within a few mins of entering the house.  (One woman had a strong allergic reaction within 10 mins and had to leave the house and use her puffer!  Very upsetting to see.)

Facts and Observations:
-The second story of the 1.5 story house was gutted and all old insulation (fibreglass and wood chips) removed.  A lot of dust had accumulated on the insulation over the 60+years.
-The second story is currently being put back together: EPS foam on attic side of kneewall and roxul mineral wool.  45s of roof, and walls of shed dormer were sprayed with closed cell spray foam.  (Sadly people seemed to be having allergic reactions prior to the demolition starting.)
-The house does not have insulation in the walls on the main floor – just heavy felt like paper with silver paper attached and thick plaster board. 
-There is no musty smell in the house to speak of – with the exception of the basement in the high humidity summer months.  I think the musty smell is from moisture wicking up through the concrete basement floor or from warm air hitting the basement walls.  There is no visible signs of water entry.  Floors are all concrete – no carpet, no cardboard boxes on floors.  Basement spring humidity right how is approx. 20-30% depending on the day.
-Main floor humidity right now is approx. 20-38% depending on the day.  It went to 38% one day when we had quite a bit of precipitation.
-The shingles were recently replaced and a synthetic runner was used as underlayment.  There was previously no underlayment.  The wood on the roof is original – long pieces with small gaps between each piece.  There were some leaks on the shed dormer.  I had all the old wood removed and replaced it with fir plywood.  A few of the rafters were dark with mold – not the fuzzy kind of mold. They must have experienced the brunt of the leaks.  They are not rotten.  I’ve washed them with soap and water and sprayed them with concrobium.  I’ve also rented a concrobium mister and misted the upstairs.
-And in general the house does not have a “fresh” feel about it like well constructed new assemblies do.  I attribute that to the lack of insulation and age of the house.

I hope I’m not biasing the discussion by seeming to point to mold as the culprit. 

Should I hire a professional mold remediation company to come in and spray the upstairs whatever they use on the off chance there are mold spores in the air?
Could it be something other than mold, mold spores?  Obviously dust may be an issue. 

Is there a way to purify the air?  My old furnace is about to be replaced too.  Should I be considering something special on the new furnace to better filter the air? 

Any thoughts / suggestions? 

It’s upsetting not to be able to diagnose the problem. It’s also upsetting that I’m remodelling a house that I may not be able to be comfortable in.

Thank you.

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  1. GBA Editor
    Martin Holladay | | #1

    Two observations:

    1. You wrote that "The second story is currently being put back together." In other words, it sounds like you are living in a house that is being renovated. If that's the case -- if you are living in a construction site -- then ordinary construction dust could be causing the reactions you describe.

    2. You didn't describe your home's ventilation system. If your house has no ventilation system, it's time to install one. Here are links to two relevant articles:

    "Designing a Good Ventilation System"

    "Revisiting Ventilation"

    1. Helpmewithmyhouse | | #6

      I hope so!
      Does it make sense to install a ventilation system (hrv or erv) in a leaky house? The rate of air exchange is already pretty high!

  2. Expert Member
    BILL WICHERS | | #2

    If you’re concerned there are airborne contaminants in your house, you may want to hire an environmental consulting company to do some testing. Note that these companies are usually doing commercial work, so they tend to not really advertise. A lot of companies that claim to do this work for residences are not exactly professional operations.

    I have found that a good place to get recommendations on reputable contractors of this type is from the people at insurance companies that pay out claims (these people are NOT the regular insurance agents customers talk to). Insurance companies do NOT like having to revisit projects, so they tend to be careful who they trust to verify things have been completed successfully. Call your agent, ask to talk to these people. You should be able to get some good recommendations for environmental testing companies in your area that you can trust to do some indoor air quality tests. The info from these tests will help you to identify the source of the problem.

    You don’t want to filter your indoor air until the test company is done testing.


  3. GBA Editor
    Martin Holladay | | #3

    I disagree with Bill / Zephyr about testing. For more information, see "Indoor Air Quality Testing Should Not Be The First Move."

    For my take on indoor air quality, see this article: "All About Indoor Air Quality."

  4. Expert Member
    Peter Yost | | #4

    As I was doing our deep energy retrofit of our 100+ year old house room by room over a 12 year period, we lived in the house, including my older daughter who is an asthmatic.

    I discovered that depressurizing whatever space I was working in 24/7 with a simple box window fan kept all the dust and odors associated with demolition and construction confined to my work space.

    Try isolating workspaces before doing anything else.


    1. Jon_R | | #5

      Similar to depressurizing the work space is to pressurize the living space. Works well in summer and also reduces contamination from non-work related things (like mold in other walls).

      Also consider HEPA vacuuming to remove existing dust that gets stirred up every time you move.

      1. Expert Member
        BILL WICHERS | | #7

        It’s generally better to depressurize the potentially contaminated area than it is to try to pressurize the adjacent area(s). The reason is that the depressurized area won’t have any leaks to the outside — any air leaks just suck into the contaminated area and go out the blower. Nothing gets out of the containment area. In professional setups (like asbestos abatement crews), the exhaust blower used to depressurize the containment area has a filter so that no contaminants leave the area.

        Pressurizing the adjacent non-contaminated area has the risk of unintentionally pulling contaminants into the supposedly “safe” area.

        BTW, I’d try what Peter suggests too as a first step if you’re actively working at the site. Air tests are more for persistent problems you can’t locate which is what I’d originally thought was the problem here.


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