What are these spots in attic?

[Nick Gromicko]

http://www.nachi.org/forum/attachmen...1&d=1209572023

http://www.nachi.org/forum/attachmen...1&d=1209572058

[David P. Valley]

Originally Posted by gromicko

http://www.nachi.org/forum/attachmen...1&d=1209572023

http://www.nachi.org/forum/attachmen...1&d=1209572058

Nick,

Those are mud dauber (WASPS) nests.

SEE THIS LINK

[Jeffrey R. Wicklander]

Either that or they reused their concrete forms for rafter joists.

[Linas I. Dapkus]

Contact an IAC2 member in the area for further analysis.

[David P. Valley]

Originally Posted by ldapkus

Contact an IAC2 member in the area for further analysis.

Linus,

It doesn't need further analysis.

Simply scrape them off with a putty knife and apply some sort of wasp deterrent to the rafters.

[Rick Maday]

Originally Posted by dvalley

Linus,

It doesn't need further analysis.

Simply scrape them off with a putty knife and apply some sort of wasp deterrent to the rafters.

What if the wasps are still there?
Or is this a residue that's left behind when they're gone?

[David P. Valley]

Originally Posted by rmaday

What if the wasps are still there?

Swat at em'

[Blaine Wiley]

Those are an everyday find here in attics, front porch ceilings, lanai ceilings and especially in detached garages. They have nothing to do with air quality, except for the hot air expelled when stung by something from an active one!

[hwalsh]

Great information everyone. Thanks.

[Ricky K. Kie]

The greenish and black rafters look like mold behind the white spotted rafters. I couldn't see any insect entrance holes on the white spots. I have however seen concrete stains like that. A closer view would tell more; and the smell of the attic would tell if it was mold.
It sure didn't look like mud doublers we see in NY.
There was also white effervescence on the brick in the first picture.
Moisture = Mold

[William M. Corbett]

They don't look like mud wasps to me either. More like a type of fungus or like someone else said... concrete. I've seen many "Dirt Dauber" nests and that doesn't even come close.

[David P. Valley]

Originally Posted by wcorbett

They don't look like mud wasps to me either. More like a type of fungus or like someone else said... concrete. I've seen many "Dirt Dauber" nests and that doesn't even come close.

I'll bet my annual salary that these are indeed mud dauber nests......

[Jeffrey R. Jonas]

Originally Posted by dvalley

I'll bet my annual salary that these are indeed mud dauber nests......

And I'll back you up David...(but with your salary, of course)...

[Blaine Wiley]

I'll bet Dave's annual salary too! I have three leftovers on my front porch ceiling. (Yeah, I'm lazy and the wife wants them down!)

[jkogel]

Mud daubers AND a couple of wet, moldy spots.
These wasps do not swarm, they are solitary, they seldom (never?) sting people and they feed on spiders and other annoying insects.