Thread: White powdery substance in attic.

I found this white powdery substance on some of the sheets of plywood and covering the attic insulation. The house was originally built in 1979, but the powder was also in areas of the attic which were added later due to additions. There was some moisture damage, but the powder was in other areas also. I suggested further evaluation, but i was wondering if anyone has ran into this before.



Thanks,
George Hoeye
Nevada Home Inspections, LLC

Similar Threads:

• White stuff on soil
• White residue on gas fireplaces
• Short Attic Ladder
• White "powder" at furnace exhaust tube
• Protection of wiring in the attic

Difficult to say for sure. From the pics, it looks like fungus and/or mold. Particularly the 2nd pic.

Inadequate ventilation?

I guess in Nevada it's generally too dry to find a lot of this?

Definitely looks like mold/mildew/fungus due to excessive moisture/humidity.

I'll take a WAG...

Entirety of original decking was sprayed with white pigmented shellac or other "primer/sealer" poss. gyp/plaster layer or immul. paint to seal "smoke smell" after the earlier fire (wood too high MC at the time) and reinsulated/sealed as part of a post fire/smoke event restoration. Shellac has since flaked & delaminated from the decking and relocated decking (raised the roof) & structural members - moisture barrier (sealer), heat, & ventillation issues.

Another WAG...sprayed ABC extingisher to put out a fire and never cleaned up...but brush marks in 3rd or 4th pic to left top side of struct make that unlikely..and more likely there was an applied substance to the underside of the older decking, some of which was relocated/raised with the "addition", and some of which was replaced.

What is that partially insulated section of vent or duct pictured below wet/black zone of decking? Whats on the other side of that untaped (spray foam!) gyp wall addition?? living space over or adjacent to garage?

I read too fast and didn't really notice the white stuff down on the insulation. I'm re-thinking the mildew/mold explanation. Also, the way it stops along one edge of the decking.
But that black area sure looks like water damage.

Looks like most of the white stuff on the plywood happened during a different incarnation, as you can see stud lines that don't line up with the existing ones. If not for that second photo, I'd agree with HG. That one looks wet and moldy, and even has a nice little fuzz of spores hanging down.

That looks like a bad vent set up in the 3rd photo, and I don't see any attic vents. Is that powdery black stuff on it dropped from above?

The OP said there was moisture damage.

What is that partially insulated section of vent or duct pictured below wet/black zone of decking? Whats on the other side of that untaped (spray foam!) gyp wall addition?? living space over or adjacent to garage?[/quote]

The HVAC duct was fully insulated (foil backed insulation), the insulation on the ends are covering the metal elbows.
It was not spray foam, but drywall mud installed with what appeared to be their finger! Which I noted in my report due to the adjacent living space. (townhouse)

I do not believe there was ever any fire damage. The roof trusses were all manufactured identically, and typically you would see some type of encapsulation (paint) of any smoke damaged wood.

The shingle roof was in excellent condition and appears to have been installed within the past 5 years, which the pounding on the roof would explain the powder on the insulation from falling off of the plywood.

I did note in my report that there was a lack of attic ventillation as there was no "high" ventillation, only the eve ventillation.

So now we know where they used the wet plywood sheathing during construction .

Townhouse, hmmm.

See, you named your photos with an address in Las Vegas of a currently listed Bank Owned single family home built in 1979 (4850 Treetrunk) which sometime, apparently after the last sale in 2005, someone converted all or part of the garage to a 4th bedroom Master and would explan the improperly installed fire separation wall, reuse of the decking or old wall sheathing (block wall & 79 stucco from the old walls previously separated from the garage now converted bedroom suite, for the raised roof over the old garage.. the recycled (flipped over) members, and the delaminated paint upon same which would have likely been formerly exposed in the former garage space. Hard to tell what that flat roof projection is in the last picture backside on the listings - can't see full front with the old pine in the listing photos.

I made the WAG before I noticed you named your photos with an active listing REO address. Strange that you now refer to it as a townhome after having stated there was an addition, hmmm. Seems there was also a garage (partial or complete) conversion, according to the listing.

At least its described as having that history re MLS 1224437 listings and realtor.com, zillow, etc.

Between the units installed on the roof, and the sat. dish, hard to determine the cause of the leak, although appears to be sagging due one of the two roof top units above.

Perhaps these photos belong to a different address? Still strange idea of a "townhome" having an "addition and I don't agree with the premiss that the framing as pictured is all "original".

Suppose you could research the colony homes #07 sub-div. and the plans & permit history for the home yourself, and of course you were there.


4850 Treetrunk Av Las Vegas Nevada 89147 | MLS 1224437

1 STORY HOME CENTRALLY LOCATED IN SPRING VALLEY, CONVERTED GARAGE WITH PERMITS ADDING THE 4TH BEDROOM AND 3RD BATHROOM. OPEN FLOOR PLAN WITH LOTS OF CERAMIC TILE THROUGHOUT. MASTER WITH CUSTOM CLOSET

4850 Treetrunk Ave, Las Vegas, NV 89147 MLS# 1224437 see first & 17th (last) pictures

4850 Treetrunk Ave Las Vegas NV 89147 - Public Property Records Search - Realtor.com®

4850 TREETRUNK AV Las Vegas NV 89147 MLS 1224437

Heck could be delaminated primer, sealer, stucco, borax, gypsum, plaster, and/or drywall dust from the crappy DIY convert garage to "separate" master bath & bedroom with custom closet, work. From the looks of that crap drywall work - someone went berserk cutting tiny blocks and spakleling them up to the rafters & roof deck with a hand saw rather than scoring and breaking, likely did it in the dang space and got drywall dust all over to settle upon the insulation over the ceiling.

Whatever the substance is the only thing that makes any real sense in my opinion is inadequate ventilation. Only a lab could tell you for sure. It might have even come in from the lumber yard in the original lumber delivery but could have spread because of a lack of ventilation. Just my guess.

Pic 1 - recycled plywood with what looks like old-fashioned whitewash. Possibly from a construction site fence?

Pic 2 - the old roof leaked and so there is some water stain and maybe black mold or other there. The clean sheets didn't get whitewashed, but there are some water marks at the end of the clean sheet by that stain.

Pic 3- No H clips and the plywood is sagging near where the leak was.

Pic 4 - The whitewash has dried and flaked off onto the insulation.

Pic 1 - I think the requirement for drywall sealing includes tape, so that mud work is a bit suspect. Check the wording for the firewall rules for 1979.

If you look closely, you can see patches of white powdery fuzz growing out of some of the white areas. I think they took moldy plywood off walls somewhere (nice 16" OC spacing), "cleaned" it off with bleach or something, and reused it. If it had been a dry attic that might have worked, but it has current moisture issues. Pic #2 doesn't just look moldy, it looks wet in spots. The problem has spread to the trusses. So with all the moisture around and little ventilation, the spores left in the plywood are growing.

Originally Posted by Kristi Silber

I think they took ... plywood off walls somewhere (nice 16" OC spacing),

I noticed that too, but I was thinking that the white stuff may have been from white Styrofoam insulation glued to it at one time? Then again, some of the white stuff was behind the 16" o.c. studs, yet it does not appear to have been wet.

I suspect that the water damaged area are from just that - water from roof leaks.

I discounted the 'used as concrete forms' because the stud marks would be on the other side (the non-concrete side) if used for that.

Could be for pest control, such as Diazinon or boric acid. Another reason to wear a respirator in attics.