What are these black stains on newly installed vinyl soffit?

[Cropduster172]

Had a new roof, gutters, vinyl siding and new soffit installed in April.
I noticed these black stains on both sides of the house a few weeks afterwards. There are aluminum soffit vents running the full length of the house directly underneath the perforated vinyl soffit a few inches in from the gutters.
Is it debris from when they cut the roof peak for the ridge vent? It rinsed away a little when I shot the hose at it. Mildew? If so why in only 3-4 sections on both sides ?

 

[demarpaint]

Hard to tell but it does look like mildew. Debris would most likely easily be removed simply but dusting it off.

 

[Analog-1]

Yep mold and mildew.

 

[shortyb]

Time for this.

Mold and mildew love vinyl siding/soffits etc. How/where it develops depends on lots of factors like humidity, condensation formation, exposure to the sun, wind patterns etc.

 

[Cropduster172]

Time for this.

Mold and mildew love vinyl siding/soffits etc. How/where it develops depends on lots of factors like humidity, condensation formation, exposure to the sun, wind patterns etc.

It has been really humid... especially here at the beach with 93 temps and 98% humidity days on end plus a lot of rain. First time in 15 years I ever had to treat the pool for algae.
I'll hit in a few weeks with a bleach solution and the pressure washer.
Just weird how it's only in certain spots.

 

[rijndael]

I'll hit in a few weeks with a bleach solution and the pressure washer.

This stuff works really well and you won't have to drag out the pressure washer:
https://www.lowes.com/pd/Mold-Armor-Mold-Armor-EZ-House-Wash-64-Fl-Oz/5013024301

 

[Cropduster172]

This stuff works really well and you won't have to drag out the pressure washer:
https://www.lowes.com/pd/Mold-Armor-Mold-Armor-EZ-House-Wash-64-Fl-Oz/5013024301

Thanks. I've used it before. It does work well. I usually just mix 1/2 gallon bleach with water 50/50 and some liquid Tide in a pump sprayer.

 

[vwmaniaman]

I second that Mold Armor tip. That's all I ever use here in the jungle of Western KY.

 

[demarpaint]

It has been really humid... especially here at the beach with 93 temps and 98% humidity days on end plus a lot of rain. First time in 15 years I ever had to treat the pool for algae.
I'll hit in a few weeks with a bleach solution and the pressure washer.
Just weird how it's only in certain spots.

It's been like a giant Petri dish around here, the perfect environment for mold and mildew. There are plenty of products available to address it, I'd attack it sooner rather than later.

 

[TCL]

I wonder what is going on with the wood/insulation behind it?

 

[rijndael]

Probably nothing. This is super common in humid environments. I have to treat my siding practically every year, usually in the late/summer and early fall. When I wake up in the mornings all of the windows (on the outside) are fogged up because it's ~100% humidity. It's worse in the late summer because the evening thunderstorms leave everything soaked all night, the humidity is too high for it to dry up.

 

[Cropduster172]

I wonder what is going on with the wood/insulation behind it?

It was in good shape in April when they pulled off the old vinyl soffit. Replaced 6 sheets of plywood on the roof but the soffits, gables and sheathing were all in great shape.