Thread: Staining on metal panel

Any thoughts what caused this staing between the two panels? It wouldn't rub off. My first thoughts is due to water ponding but the roof slants left to right in the photo.

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Those stains are too consistant looking in appearance on each panel in my opinion to be water staining.

For a SWAG, I'm going to say it is some type of material maybe placed on the material when they those panels were stacked together and shipped out. Maybe some type of adhesive.

Thats just my quess.

Rick

My guess is that it is algae/mold/mildew/whatever in that area because the overlap allows moisture to stick around longer - the roofing material stays cooler. Does anyone buy this explanation?

John, I was thinking along those same lines before reading your post.

I would consider the possibility that there is some type of gasket/sealant sandwiched between the panel overlap which will allow the panels to stay just a little cooler, just a little longer and thus a little more moist every time it rains.
Then you get a little growth or just a collection of more dirt.
But that is just a WAG.
But then Rick's idea has merit too.

Bottom line, I would not be too concerned, curious, but not concerned.
Jim

Jim,

Interesting, but note that the 'stain' won't rub off.

If there was a collection or growth of something it would seem that you could at least rub some portion of it off the panel.

Maybe corrosion from the back side where it stays wet under the lap???

Thanks, all.

Well there are other defects on the roof system, so just to CYA I'll note the staining and recommend contractor determine cause and if repairs are needed.

I'm thinking that there is some type of sealant material between those two sheets, and that the 'stain' is from the equipment used to press the two sheets together or maybe heat them to set into the sealant better. Rubber tire/bottom cushion which has been coated with asphalt/deteriorated/something and it left its mark while being moved across the metal when the roof was installed.

Jerry,

Would you comment on the staining or not? If so, what would you say about it?

Dan,

Provided that the metal roofing looks good, I would put it in my report along with the other things you found on the roof, then tell (tell) my client that I doubt there is anything to worry about, but, if they are at all concerned with this, given everything else I found, by all means have the roofer give it a look when they are on the roof making the other repairs.

It is now "in" my report, provided that nothing looks wrong and the metal looks okay - I feel that it is nothing more than 'cosmetic', which would be in the same category along with chalky roof paint (yeah, that 'eventually' will reduce the life of the metal roof), and it leaves it up to the roofer to say something bad about it - if something bad needs to be said about it.

If the metal looked good (not rusting or corroding, not bent or otherwise damaged) and that was only on the finish, to me, that's not a problem, and I would relay my feelings toward that end to my client - and make sure he knows that is it no sweat off anyones back (meaning it does not bother me) to have the roofer look at it when they are on the roof (which, from your photos, they need to be anyway). Which means I've done as much as I can and it is now up to the roofer (one which specializes in metal roof) to give it the thumbs up or thumbs down.

But we HIs do things like that everyday, day in and day out ... 'yeah, I think it's no big deal, but if you would feel more comfortable getting ... to look at it, feel free to do so ... '

It comes down to how you handled your clients expectations from the beginning.