Vinyl Siding - new unseen discolouration, input?

Any information on this siding discolouration , would be greatly appreciated. As this is new to me and was only noticed on the rear portion of the home.


A couple of questions Evan?

What is the siding material?

Is the rear of the house facing North?

Are there eaves and soffits above that area of the siding?


Looks like vinyl siding. Is it stains or discoloration in the siding?


vinyl siding
has gutters installed
metal roof covering
rear of home is westerly facing
soffit overhang roughly 16 -20 inches deep

hi junior.

appeared to more discolouration but in a consistent pattern.
thought it was staining from weep holes are first , but that wouldnt have given the uniform pattern down the siding , would it ?

It almost appears that in this area that an inferior fastener may have been used which may have caused the discoloration given this, I’m unsure how to best describe this finding

Here is a good article for further reference;

Just from my view, I would first think of it as sort of water staining with penetration coming from somewhere above and working it’s way down behind the siding. Not sure if vinyl would stain or discolor like that with only water.


much appreciated Thomas ! I will give a read over before supplying my recommendations in the report!

Roof conditions were good?

roof conditions, appeared in good condition, frosting on the underside of the roof sheathing ( it was -18) at time of inspection.
no missing fasteners above this portion and gutter was in decent condition. newer vinyl exterior patio door.
this is on both sides of the rear patio door.
it has stumped me abit to be honest.

Possibly stains caused by ice dams at some point. Did the stains start close to the soffit?


here is another photo … from my photos and memory it start approximately 2-3 courses down from the soffit.

It is from washing the siding and not doing a thorough job of scrubbing and rinsing.


I wouldn’t count it out but I don’t think so as I don’t think anyone could be this inconsistent, consistently :joy: :joy:. the Uniformity of the marks is what caused me to do a double take. The weep holes aren’t even line up like that.

It’s just discoloration? The surface is still flat?

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hey Daniel ,

yes surface was still flat no apparent warping or material distortion. Thoughts ?

It is just a shity cleaning job, it will most likely clean off,


quite possibly - wanted to check here first to see if anyone else has seen this before.

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I have vinyl siding on my house and if I don’t brush and rinse completely it will leave a residue.


I’d agree with Scott, after seeing the last photo.