I've noticed some black spots on the bare cedar siding of my house and I'm trying to figure out what they might be. Some look like smudges, but I'm concerned that they could be mold. I'm hoping it's just from the tannins in the cedar due to it being exposed to the rain for over six months now. To give you some background, we were supposed to paint the house last November, but the weather didn't cooperate, and the painters could only fix some bad siding and couldn't finish the project. Now we're waiting for our windows to be changed before we can proceed with the painting, so these bare cedar sidings have been subjected to harsh weather like snow and heavy rain for quite a while. Here's a link to some pictures: https://imgur.com/a/s77jbuO
2 Answers
It looks like you might be dealing with a mix of weathering, mildew, and potentially tannin staining, which is pretty common for exposed cedar. The good news is that it’s fixable! Make sure to clean the surface with a wood cleaner to eliminate the spots and any mildew before painting. Let it dry thoroughly, then use a high-quality stain-blocking primer to seal the wood. This should prevent those tannins from bleeding through and ruining your new paint job!
Honestly, those spots look like mold to me. It's kind of unusual for the exterior, which might indicate a bigger issue, especially if there's a window nearby. If you have anyone in your house with respiratory issues, I'd recommend taking this seriously. Maybe consider removing some of the siding to check what's going on underneath. If everything is fine on the interior, sanding and painting might be your best bet!
Oh no… do you think it could be an installation problem with the window? There’s one nearby in the photos, but it seems like that wouldn’t affect the black spot above the glass door.
I have allergies too, so I totally get your concern. Hopefully, when the painters come back, they’ll be willing to take a look to make sure everything's safe before painting.