I have some stains on a new composition roof that I believe are due to surfactant leaching from the paint on some concrete caps above the roofing. The caps were painted (stained) this fall just as the nights and mornings began to cool and it is my understanding that the leaching can continue through the wet season. I am concerned that the light colored stain will permanently discolor the charcoal shingles. Do you know of a good way to remove? I have a few photos if that helps.
Thank you,
Paul
Replies
Paul,
It would be helpful to be able to see the picture to help determine how bad it is.
Here are some photos. You can see the light gray streaks on the shingles. The shingles are difficult to get to and my concern is the stains staying on too long and permanently damaging the shingles. I don't want to scrub the shingles to hard and remove the granules.Thanks,
Paul
Paul,
For those of us "country bumpkins" on dial up those file sizes are too large to deal with.
Can you resize them a bit?
Thanks, Walter
Try these, I can make them a little larger if you cannot see.
You reduced the size too much. Rather you need to reduce the resolution and but not the size as much.Better take the 2nd one full size. Then start by clipping it to only show the upper left corner.That shows the worse of the problem..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Here it is cropped..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Impossible to tell from the pics..but are you sure the caps were painted w/ a latex paint (and in conditions which would cause leaching?) If it is surfactant leaching, a mild soap and water wash (e.g. dish soap) should remove it.
Or just do nothing at all. Every paint manufacturer I know of says the stuff is harmless and will eventually go away in the rain or from mere evaporation. In my experience this has always been the case.
If it's masonary it could also be lime leaching out, in which case a mild acid wash would remove it.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
Looks like lime to me too, try some white vinegar in a pump up sprayer, it will probably return in the future though.
I hadn't thought of lime. The caps are concrete, made by cultured stone. The mortar was set in July or August (Seattle) when the weather was warm. They were stained because the color was incorrect and costs/timeline prohibited switching caps. I will give some of these solutions a try.Thanks
It is a latex based concrete stain from Benjamin Moore over a Zinser primer. I have heard it will go away over time but I am just concerned how long it will take and that the client will not want to tolerate it on the house.Thanks for the reply,
Paul