Attic covered in... what is that?

Hi all,

I have been reading your forum and am blown away by the amount of information and knowledge shared here.

I am looking to purchase a house and recently had one inspected by a recommended HI. At first he balked at accessing the attic due to limited access. Issue was a/c ductwork laying over the access area. He agreed to look if access was provided. Sellers were dumbfounded as their contractors never mentioned an issue. Fast forward… I agree to help by leading the way. Once access I available we both snap some photos. His feet never leave the ladder. He said it is too tight due to a/c.

In his notes he mentions a “dust-like substance” and unhealthy conditions. That’s not enough for me.

I tried to provide photos as I am seeking your help. Obviously, there are bath fans improperly venting into the attic space. That is a fix that will be addressed. My concern is around the white substance. It coats every surface. Ductwork, insulation, wood. One a/c duct run does not have a coating of white as it was probably replaced. A pest inspector said all was clear. His main focus was termites, however. Any idea what I am seeing up there?

Thanks in advance for all of your assistance.


Is this a bath vent without any ducting?
Did someone do some drywalling recently with the fan open to the attic?

It is definitely a fan/vent from somewhere. Do not see any duct or piping away from it, and you can see the fan inside through the hole on the side.

Dust from sanding drywall mud is a good thought. Hard to say for sure, but the fan venting needs to be fixed.

You are correct. That is a bath fan venting directly into the attic, not through the roof. Both upstairs bathrooms present this issue. There is no apparent recent work done in the bathrooms. Both are dated. The fans may have been replaced but the roof is said to be 12-15 years old and no signs of venting.

Its usually powdered boric acid pest companies dust the attic with to control ants. Safe to touch or breathe. Start there.

You need to be very careful when making statements like that!!!

Read your post again, there likely isn’t 20 grams in the whole attic, but at least it shows you know how to use google.

Typical of you.

Tell it to the new homeowner that has sensitivities to it, or should I say to their next of kin?

Peanuts aren’t harmful to the majority of the worlds population, but to the one person who is hyper-sensitive…

I guess it’s fitting that you posted on Memorial Weekend!

Well I do have two young children and a small dog. Their health is of the utmost concern to me. This “stuff” has to go.

IF this is a boric acid dust application, how can I confirm that? (Short of doing my own chemistry experiment and burning it safely and looking for a green flame). Is there a possiblity it is some form of mold/fungus?

My understanding is insecticide dusting should be applied in limited quantities indoors. Pretty much the opposite of what is seen here. How would you recommend removal and cleanup? Should I assume the need for replacement of all insulation and cleaning of other surfaces (wood/ductwork)?

The current homeowners have informed us they have not had any pest treatments in the attic. This would seemingly rule out boric acid. Any other ideas? Who would be the most appropriate to test this material?

Ask the county health department.

In photo 34HD2r6.jpg there are dry leaves in the picture. Is there a soffit vent that is allowing dust and debris to flow into the attic?

depends on state regs
indoor air quality specialist is best source for investigation-testing
i wouldn’t hire any hi that offers sampling as ancillary services
if you’re the proactive type
contact local lab for sampling protocol, get sample, have tested
unless there is copious air leakage from attic to living space probably a non-issue and just an accumulation of environmental dust settlement
i’ve seen much worse

How about a whole house fan ? Looks like dust to me.

@Daniel - good catch on the leaves. I noticed that as well. I have no idea how those ended up in the attic. When I popped my head up there it’s completely dark. There are no signs of a point of entry. The roof is 12-15 years old, and it’s possible some plywood was replaced at that time…maybe they came in then? I haven’t been told they had any ‘visitors’ that needed removal, but that’s another possibility.

@Sam - There is no sign of a whole house fan. The more I stare at these pictures the more I feel this is some form of dust/debris. I do wonder if the bath exhaust fans blowing mixed with some ceiling drywall cuts could be the culprit since the dust does appear more white in than grey. Each of the 3 bedrooms and a hallway had ceiling fans installed at some point, although none of the work seems at all recent. All would have required holes into that attic space.

Overall I’m wondering if what needs to be done to start: the attic needs to be cleaned of the dust (not sure of the best method), all insulation replaced, air leaks sealed, bath exhausts properly vented through the roof.

As has been mentioned, it looks like drywall dust. If you’re really worried, call the county health department and ask who you should contact for laboratory analysis.

Where are you located AndrewSD?

I am located on Long Island, NY (Nasssu County).

All the dust and leaves mean it needs to be sealed and save homeowner$$ in heating/cooling and they don’t have to breathe funky attic air. Also br vent needs to be outside not end in an attic. Our inspector didn’t even step foot in our attic when a big snakeskin was sitting right next to do. We found these same problems on our own.

Based on your pics with the AC ducts laying all over the attic and what looks like low headroom, I think to be safe to themselves and to not damage ducts, ceilings, etc many inspectors would not travel that attic unless a significant visual problem was noted.

Although wrong by current standards, bath vents have been dropped into the attics for 20 yrs or more in many areas of the country.

That attic pics look like 90% of the older home attics I see.

Chemistry / dust analysis goes well beyond what a home inspector typically does.