In a previous blog today, I showed a photo of two gutters that were full of debris and water was running out of them onto the structure. At the same home, here is a downspout that is the site of decay of the T1-11 siding. It could be that the decay is, in part, due to a blockage of the downspout at the elbow. On the other hand, I think it probably more likely that, in this wet and shaded location, the rain is traveling on down the the outside of the downspout. This downspout gently slopes against the side of the home and has lots of surface contact. Clearly, it would be better if that surface contact was minimized. Anything that retains moisture against the siding is a problem, especially in shady locations where the moisture is retained for weeks or months, depending on the season.
Thanks for dripping by
Steven L. Smith