White substance on attic rafters

Any idea on what this stuff would be? Causes? etc. etc. I have seen white mold-like substances in attics before, but this didn’t appear to be.



Very difficult to tell from photo’s (need close up for better idea) but looking at the pattern of the “stuff”, I suspect it is from when the home was built. Could be mud, concrete residue from using the lumber as forms, or just poor/sloppy job site conditions.

Any more info? Did you touch the “stuff”? What did it feel like? Did you give it the level II taste test? :wink: Age of home? Close-up pictures?



I would note it as " Job site construction related debris, possibly paint, drywall mud, concrete etc. prior to installation."

This is on some boards and not on others boards attached.

Unless, there has been major roof damage in the past and this crappy lumber was brought in to do repairs.

Either way it does not look like a concern.


I agree…it’s probably either construction debris or whatever skin disease Michael Jackson had…either way, not of much concern.

lol :slight_smile:

I agree. Loos like form wood. Quite common in older homes like that.

The white powder that you have shown, I have seen on many of my inspections, I received some feed back from a mold specialist that indicated to me that it was a type of mold that had dried up and offered no harm as long as it was not present in the living areas. But when I would write this up I would indicate suspect mold and it would have to be tested.
I also was told by another inspector that has many more inspections under his belt than I, This substance was dried up wood sap, which I find hard to believe. So as far as I am concerned there is no real definitive

Hey Billy Hows life treating you.

Time to tell your mold specialist that he needs to take some sort of course on mold. Mold anywhere in the home is NOT OK in elevated levels whether it is live or dead. Molds release microbial volatile organic compounds when it is live or dead. This is what causes people to develope allergic reactions over prolonged periods of time from chronic exposure.

I agree with the mold guy needing to take some kind of course. However, if the mold guy saw this personally and identified it as mold growth, he should actually be taking a refresher on how to recognize mold growth. The patterns on the wood are not indicative of any mold growth I am familiar with. I agree with it being concrete.

What direction does that roof slope face? Was there any “white stuff” on the opposing slope?

Was there any white stuff on the exterior of the roof?:stuck_out_tongue: Sniff it and see what happens.

I also think its benign. You can see that the roof is nicely framed and there’s not much insulation - so this is an old house. It was common for lumber to get dirty, stained, splashed with concrete while it was piled up in front of the house waiting to be used. And sure, some of it might have been used lumber. My own house is built entirely from used lumber!

That said, the usual disclaimers apply …:wink:

That’s definetely from concrete. Either from having been used as form material or being on site close to foundation during concrete pour or both. I also agree with Mike’s (in Austin) theory, now we know the source of Michael Jacksons skin disorder (concrete). Have ya’ll seen Sammy Sosa, he’s also got it now.

HA HA HA who knew this thread would go comedic

Thats not mold because mold growths will not have a sharp line edge. Also if the type of mold is considered toxic in the livingspace, it will be considered toxic in the attic. I have found, when tested that most molds in attic are not considered toxic. Most of your roof leals will test considered toxic though.

Thread revival but it seems appropriate. Attached are some photos of a white substance that I found recently on home inspection. The substance appeared primarily on the wall where the fan is located, however it appeared in a few other locations as well. It is a white, soft, chalky material that looks a lot like drywall dust.

Any ideas? Could it be some type of chemical for pest control?


Somebody killed the Pillsbury Doughboy in the attic?

No, that is not it. Sorry, I really have no idea

From the pattern
it’s obviously a spray of some sort.
Very possibly for pest control as you mentioned.

[FONT=verdana]Same whitish staining.
Suspect: Plaster of Paris for damaged drywall repair in the commode.
Look at the Attic view of the venting can and hose.
They must have had an air handler moving the air out the gable venting.
Pour repairs everywhere.
Owner stated it was his nephew.

Pics in thread.
I agree with construction lumber.
Somewhat common in attics.
Seen lots of foundation by 6 or 8" s for flat decking or slope to the drain on pre 60’s homes in my area…