Discoloration on roof sheeting after storage

[Chronaus]

On the roof sheets from Lindab we received, it states that they should not be stored outside due to potential discoloration that may occur due to moisture between the sheets.

Unfortunately, we will not install them until spring. They are now lying on pallets under tarps and still in their packaging. They are black tp20.

Has anyone experienced the discoloration Lindab warns about?

 

[Nissegandhi]

On the roof sheets from Lindab we received, it states that they should not be stored outside due to potential discolorations that might occur due to moisture between the sheets.

Unfortunately, we will not be installing them until spring. They are currently on pallets under a tarp and still in their packaging. They are black tp20.

Has anyone experienced the discolorations Lindab warns about?

If water gets between the sheets, something commonly referred to as "white rust" can easily occur, which is a common phenomenon.

 

[Chronaus]

If water gets between the sheets, it often leads to something called "white rust," which is a common phenomenon.

Even on black sheets?? I thought white rust was related to galvanization and that's beneath the paint...

 

[Nissegandhi]

Even on black plates?? I think that white rust is related to galvanization, and that's underneath the paint...

Yes, on all colors.

 

[Chronaus]

Excuse me, but how? Then the paint must disappear before the zinc oxidizes?

 

[Nissegandhi]

Excuse me, but how so? Then the paint must disappear before the zinc oxidizes?

Unfortunately, I can't explain how it works, but since I've sold sheet metal for many years, I know that it is so.

 

[Chronaus]

Unfortunately, I can't explain how it works, but since I've sold sheet metal for many years, I know it's like that.

OK. And how big are the blemishes we're talking about, and can they be removed from black sheet metal?

 

[Nissegandhi]

OK. And how big are the blisters we're talking about, and can they be removed from black sheet metal?

It depends on how much moisture there has been; in any case, one should avoid white rust.

 

[Chronaus]

It depends on how much moisture there has been, in any case, one should avoid white rust.

Yes, I understand that, I just can't find a single picture on the entire internet where a painted sheet metal has gotten white rust. As long as it doesn't rain on them, they should be okay anyway!

 

[Nissegandhi]

Yes, I understand that, I just can't find a single picture on the entire internet where a painted sheet got white rust. As long as it doesn't rain on them, they should be okay anyway!

It's enough for the ends of the bundle to get wet, then the moisture is drawn in capillary.

 

[plåtrickard]

It is enough for the ends of the bundle to get wet, as the moisture will be absorbed capillarily.

The ends are also untreated, so from there it might cause white rust.

 

[Chronaus]

It is enough for the ends of the bundle to get wet so the moisture is absorbed capillary

The ends are also untreated, so that's where it can turn into white rust

I'm totally on board with that, was mostly thinking about how white rust could form in the middle of the sheet!

 

[Chronaus]

The ends are also untreated, so that's where white rust is likely to form

Can it be wiped off then?

 

[Nissegandhi]

Can it be wiped off then?

How good and practical do you think it sounds?

 

[Chronaus]

How good and practical do you think

How good and practical do you think it sounds?

Hmmm what do you mean? That the galvanization has worsened or? If I just need to wipe off the sheets before assembly, it is 100 times easier than getting them under a roof.