Stained 3 Tab Shingles

'05 house in Port St. Lucie, FL. The shingles have a rust-colored stain consistent in the same locations vertically up and down the roof. I am thinking that this is some kind of mfg deficiency. Opinions please.

I saw staining in a similar patern, and found out the owner had moss up there and when he removed it roof was stained. But i’m just throwing out a complete guess…

with enough moisture present underlying fasteners that are improper and not corrosion resistant can bleed rust onto roof or wall applied shingles of any type

if tabs were lifted to investigate or nail corrosion was evident in the attic this “potential cause” could have been confirmed or excluded onsite

although corrosion resistant fasteners are required in many applications and have been
corroded fasteners are routinely found on new shingle installations, at least in Texas

Acid rain…:wink:

It almost looks like the tar is “Bleeding” between the tabs.

I’m with Barry on this one.

Barry is correct. With the costs of producing shingles skyrocketing, other materials are being used; with poor life results.

You get what you pay for, and pay for what you get; poor quality, IMO.

Proper galvinized nails are higher in costs than regular nails. Is cheaper better?

Look in the mirror also when it comes to HI prices.

What Barry said. You can easily see the nail pattern in pic. 1.

Could have been confirmed on site.

I don’t think it is the nails, b/c there would be consistent staining horizontally as well as vertical.

We see consistent vertical staining here, in ‘columns’. Nails are indiscriminate.

I will send the photos to a roofer friend.

I think Barry’s right too. Moisture would carry rust stains vertically down the roof, consistent with the photos. Also, it’s worse in the valley where runoff is concentrated. There are 2 columns that are rust free for a ways and I can’t figure those out. One might be where the roof is protected from prevailing winds by the chimney, but the other… I don’t know.

I had wondered if there hadn’t been overhanging trees there at some point before the inspection?

It’s too uniform for tree damage.

I checked with my friend who is a local roofing contractor.

Because the roof is so clean, he thinks someone sprayed bleach (terrible idea) on the shingles and that caused the nails to corrode.

An uneven spraying of the bleach could be why there are some columns of non-corroded nails.

Im still going with my guess of the tar Bleeding. If the nails were the issue the dark stains would not be the darkest at the gap between the tabs. There is no nails at these locations. The stains are fading, so obviously something is washing down the roof. But each individual stain only runs for about 6", guessing from the pics. Probably a manufactures defect in the tar nailing strip.

The slots in the shingles is precisely where the nails are located. This being a FL home I suspect there are two nails at the top of each slot (for high wind locations). The lack of stains in some areas can easily be two different nail guns going using different nails out of different batches / boxes.

If you have ever done any roofing you know that the shingles are typically installed vertically in one area before the installer moves down the roof. It makes it easier to keep all the rows lined up and the installers can adjust as needed. It when an amateur tries to go down each row before starting the next the whole thing gets off (seen it many times). I live here in FL and find rusted roofing nails ALL the time (just this week in fact).

:slight_smile: I was drawn to that but???
Now look at photo 2.

What did the attic space look like?
AC venting?
Cool attic space?
Just asking.

True, that’s exactly where nails are located and probably right about the 6-nail pattern.

Manufacturing defects related to adhesive strips are inadequate amount of adhesive or poor mix design, both relating to reduced wind resistance.

This is one of the few times it would have been OK to break the bond to check some fasteners, because with corrosion like that, this roof is going to fail prematurely. Any roofer who made that mistake could have made others.

Were there any rusty old Swingline staplers laying on the ground in the yard?

To check for galvanised or corrosion resistant roofing nails (fasteners)
a. flat bar b. adhesive.
In the media follow the unsealing method only

Note observed fasteners and location. Written, voice recorded, photo and/or video medda.
Reseal the tab with plastic cement or rapid set polymer construction adhesive…

Do not attempt this unless you are confident.
Older shingles, hot deck and other issues may make it impossible. Just move on.

I recommend written permission.
Remove a tab.

1.) Staining between rafters/trusses?.
2.) Is the staining pattern 36" inches wide?

Possible theory.
Was the self seal strip’s protective covering removed.?
I have read this practice is done for several reason.
Regional in nature; Shear, Temperature of installations.

2.) Two (2) installers.
Both working vertical courses.

One removes the self sealing tar strip (protective covering) as some manufactures recommend in high wind areas.
The other installer avoids the practice. (Apprentice, not concentrating, illegal drug use or, alcohols lingering effects, etc)

IS the staining blended/blending in to cover the deck??
during instalations the lead roofer recommends to remove the sael seal propectent layer.
He oblidges to a limited capacity.

Why every 36" inches? then no staining Chris?