Plaster Walls, Old Cellulose Insulation, Moisture?

3 years ago

Hi all! First time poster here, hopefully this is the best place for this question.

We live in a 1929 Colonial, which I love, but holy heck has it given us nonstop issues.

My most pressing question right now is related to older cellulose insulation behind plaster walls.

I've always noticed an "old paper" type of smell from these walls. I've removed outlet covers to get a better whiff, and for sure there's a paper-ish smell. My first fear was mold.

I had a mold company come out and test, and I specifically had the guy smell the outlet. He was not concerned. Air tests were within normal range.

Then I had an insulation company come out to assess (it's on our list to insulate for better noise reduction and temp control). I had him also smell the outlet, he said "it just smells like old cellulose" and wasn't concerned. From what he could see behind the outlet, there is old cellulose insulation behind the walls, but it was loose and likely not installed in the best way.

Between these two professionals, I should be at ease that there isn't mold behind our walls, but I'm still feeling unsettled about it (gut feeling type of thing). I went around with a moisture meter and all of these walls have higher (but not wildly high) moisture readings than the newer walls in our house. For example, my moisture reader (the flat kind not the kind that pokes holes) on the masonry setting has anywhere from 25% - 32% moisture on these walls (higher end is closer to the windows). Windows had been updated in the 90's (I think).

From the research I've done on cellulose, it says newer insulation may smell at first, but then dissipates as time goes on. That's clearly not the case here as the smell has remained or perhaps gotten worse or stale from moisture??

Anyone have experience with this and can share insight? Would love a shared experience for peace of mind!

Sort by:Oldest

Comments (3)

Travis Johnson
3 years ago
It does have a certain smell to it. i think dehumidifying would go a long way for you. I live right on a river so there is moisture in the air, so dehumidifying snd buying plug in air fresheners get us there.
helpmehelpthishouse
Original Author
3 years ago
Our backyard backs up to a river too! So yes, definitely more moisture in general. I know the material is basically recycled newspaper, so the smell makes sense, I'm just paranoid about mold being somewhere we can't see, and these walls are in common areas plus all of our bedrooms (including my small kids rooms). Do you think adding more new cellulose insulation would be helpful, or potentially harmful? This is what I'm currently on the fence about. As for a dehumidifier, I'd have to purchase and place quite a few since this impacts various areas of the house, but something to keep in mind for sure, thank you!
Related Professionals
Mobile General Contractors · Sedalia General Contractors · New Haven General Contractors · Binghamton General Contractors · New Orleans Home Builders · Murrieta Home Builders · Hobbs Home Builders · Salt Lake City Home Builders · Chambersburg Bathroom Remodelers · Jackson Bathroom Remodelers · Sheboygan Bathroom Remodelers · Temecula Bathroom Remodelers · Vancouver Bathroom Remodelers · Sedalia General Contractors · Muskegon General Contractors
Emily L
3 years ago
I had a ton of mold issues in our 1980s house in Texas. It was in our air ducts. We had it cleaned out twice in a few years. The only indication was the mold visibly appearing on the outside of the duct registers, and maybe sometimes a slightly mildewy smell but not usually. So it might be something else you're smelling, especially given the contractors. And even if you had some, at least it isn't blowing around your house, just saying... One thing that was helpful for us was putting a hygrometer near the thermostat so we could ensure it stayed below 60-70 percent humidity. That will tell you whether you're in need of multiple dehumidifiers or not.