Black marks

[tunatussle 14]

Having trouble removing the black stains around vents at top of siding on vinyl homes. Have tried house wash, citric cleaner but it does not want to come off.

Open to any ideas on how to remove it.

[squirtgun 122]

Try using a butyl based cleaner.

[Adrian 155]

Are you sure it is not artillery mold or sometimes called shotgun mold? That stuff is next to impossible to remove.

[Rodney 14]

I use to have trouble and kept tring different soaps.Dwell time make a difference also. Butyl cleaner that i use for gutters works good on siding

where run offs from the gutters get on the house.

[tsutherland 14]

I agree with Scott here. Try using a butyl based cleaner.(Test whatever chemical you choose on a small, inconspicious area). Not all vinyl homes have coloring all the way through. There is nothing worse that having a tan house with streaks of white showing through.

You may need to use a soft brush and an extension pole to take it off.

Good luck.

[Aplus 525]

Having trouble removing the black stains around vents at top of siding on vinyl homes. Have tried house wash, citric cleaner but it does not want to come off.

Open to any ideas on how to remove it.

What you're looking at is likely mildew caused from hot moist area venting out of the attic.

If you're not using chlorine in your house wash mix, now is the time to use it. If you are using chlorine, try increasing the strength. If necessary, stick the hose of an xjet directly into a jug of 10.5% chlorine and spray that area.

Not likely it's artillary fungus if it's that high up on the house. The only other thing that I've seen cause black stains like you describe was from dark caulking that streaked.

[CLASSICPW 14]

I agree with Aplus, it's mildew from attic moisture, I encounter it almost daily. I use pool chlorine in my house wash, it usually takes 2-3 wash and rinses with the x-jet to remove it.