White powder. Client concerned.

[Ernie Simpson]

I got an email from a client from a couple of years ago. The home was a 60's ranch. His contractor noticed a white powder coming out from between the boards forming the subfloor (pictures attached).
This doesn't appear too dire, but he is concerned and interested in what this could be. I normally would have assumed that was something like a Diazinon powder that people used to spread along the sill headers, but this stuff is coming through the floor boards.
Any ideas?

[Bruce Ramsey]

Are there hardwood floors on the finished side?

One treatement to squeaky hardwood floors is to pour talc/baby powder on the floor and see if will work its way through the tongue and grove joints to lubricate the squeak.

[Jerry Peck]

Powder post beetles or old house borers?

What say one of you pest control guys? (I've been out of it for about 6 years, so I'm a bit rusty on them.)

[Raymond Wand]

The second photo indicates that something has leaked down from above and onto the joist.

Could someone have used liquid floor leveler that has leaked?

[Dom D'Agostino]

I agree with Bruce, baby powder or corn starch.

Both are used to minimize the squeak in wood flooring.

[Kristi Silber]

I agree with Raymond. To me it looks like the pattern left by something liquid. It looks just like the salts left behind after watering a plant with hard water. But I can't figure out how that could be the case without other signs of water damage. Carpet shampoo? Need more details - what's above? Type of flooring and where? That's a lot of baby powder to work itself through to the subfloor like that, and wouldn't you expect a different pattern, reflecting how the flooring was laid?

[Raymond Wand]

Kristi

To me, it looks like a one time stain.

[Ernie Simpson]

Thanks all. I actually think it is talc powder. I mentioned this to him originally but didn't know they used this to stop the squeaking on wood floors. At least its the most logical explanation.

[Ernie Simpson]

Or could be some type of floor leveling compound also. As long as it isn't asbestos...

[Kristi Silber]

Actually, looking at the photo of the joist, the subfloor does show signs of moisture where it meets the joist, apart from the white stuff. Maybe they're unrelated.

In the first photo it almost looks like the stuff discolored the wood, made it paler.

Raymond, I wasn't disagreeing with you - my plant pot analogy wasn't a good one or well-worded...meant to say only that liquid can leave that pattern of deposits behind. I agree it wasn't an ongoing thing.

Floor leveler seems a reasonable explanation.

[Raymond Wand]

Kristi wrote in part:


Raymond, I wasn't disagreeing with you - my plant pot analogy wasn't a good one or well-worded...meant to say only that liquid can leave that pattern of deposits behind. I agree it wasn't an ongoing thing.

I know. ;) But I liked the plant theory anyway.