insulation black due to air infiltration

[lilacrosie]

hi, i'm trying to deal with an attic problem. black insulation to be exact. i immediately thought it was mold but there is no odor, mustiness or moisture up there. house is only 11 years old. i have had mold people come in and of course they all say it is mold. no tell tale signs on the wood surrounding the insulation. no wetness/dampness when you put your hand behind the insulation. could this be something to do with my wood fireplace? i use it all winter. I don't want to be taken for a fool. they all want mega thousands. if it's not mold i'll pull the stuff out. thanks for any comments and/or thoughts.

 

[GDPossehl]

Where is this in relation to the fireplace? When you're burning a fire, can you feel the warm air or see any smoke through there?

 

[JCByrd24]

It could be either mold or soot. Air leaks will carry moisture with them and condense on cold surfaces, which can then cause mold. Other times of year it might be perfectly dry as it is now. Air leaks would certainly carry soot too but I don't think it would have spread that much from the leak point.

 

[Kevin54]

lilacrosie.....Welcome to Garage Journal. If you would, could you put you location in your profile? At times it helps to answer questions. Thank you.

As far as the black, I'd be leaning towards the mold side. You have a plastic vapor barrier so that would help retain moisture if it is coming from the other side. Is your house brick by any chance? And the black mold, you won't smell it like the other greenish gray musty mold.

 

[tcianci]

Everything that's black is MOLD!!!! RUN!!!!

Ha haaa. That's dirt, just plain old dirt from air moving through your insulation. You can't have black insulation and perfectly clean lumber next to it and call it mold. It's an extremely common situation.

 

[Rockcam]

Could also be from a lack of air sealing.

Fiberglass stinks at stopping air movement, but is commonly used as an air filter. Small amounts of air going through your insulation over time can certainly filter a lot of dirt.

Greenbuildingadvisor.com is a great spot for info.

 

[CNGsaves]

Everything that's black is MOLD!!!! RUN!!!!

Ha haaa. That's dirt, just plain old dirt from air moving through your insulation. You can't have black insulation and perfectly clean lumber next to it and call it mold. It's an extremely common situation.

^ ^ ^ +1 that OP just has dirty insulation.

Unless he has had lots of roof leaks to provide moisture up there, it's just dirt.

Mold would have been also on the plastic vapor barrier . . IF . . it was mold as the moisture would have pooled on the vapor barrier after saturating insulation.

 

[404]

Probably air leaks. Fixing air leaks in the attic is a lot of work. IN my case I had to take out every scrap of insulation and pile it in my back yard. It was a really really big pile. Then vacuum up all residual dust in the attic or the foam will not stick. Now go up with cans of spray foam and seal up every ceiling light box, wire, vent pipe, and wall to ceiling joint (the drywall joint on interior and exterior walls). It takes days and days and is a giant pain in the ***.

It is very detail oriented work. Basically every hole or crack that goes up to the attic must get foamed.

 

[The Cobbler]

is the plastic on the conditioned side of the insulation or on the atmosphere side? it looks to me that its on the atmospheric side of the house. is that common in your area? normally vapour barrier goes on the conditioned side .

 

[MagKarl]

Did it all start out pink? My house is insulated with Ecobatt brown insulation that looks similar to your first two pics.

Air infiltration/ventilation is not necessarily a bad thing.

 

[NUTTSGT]

I have a wood burner in the garage and I have seen some insulation that looks like that. I just attributed it to the smoke creating more "dirt" in the air than a place without a woodburner/fireplace.

 

[JCByrd24]

Air infiltration and ventilation are not the same thing. Air infiltration is bad. It drags moisture into places you don't want it, like wall cavities and insulation, leading to problems like mold and rot. The building science/code world is very focused on reducing air leakage/infiltration right now because insulating and building practices of the last 30 years have greatly reduced the drying potential of wall cavities.

https://www.energycodes.gov/sites/d...uide Air Leakage Guide_Sept2011_v00_lores.pdf