Roofing/Chimney siding



I have been told I need to get the siding on my chimney replaced because it is rotten along the bottom where it meets the roof.  Currently the siding is cedar that runs up and down the chimney.  One of the quotes I have is to replace the siding and run it across the chimney, or horizontally.  I was told this was better at diverting the water so that future rotting could be minimized.  

The siding on my house runs vertically so to have the chimney siding run horizontally would be a little different look.  On the other hand, I don't think it would be particularly obvious because the chimney and other siding are not right next to each other.

Do you have any opinions from a roofing engineering perspective as to whether horizontal siding or vertical siding is better on a chimney?  

Thanks for any advice you can offer.

I don't know what kind of siding you have but generally you do not run it vertically. Water will not drain properly and if it is wood it will rot prematurely and can easily be a leak. The water needs to run away from the seems. If you run it vertically it runs into the seams.



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Brad Zacharia


All aspects of residential Roofing. This includes shingles and flat (low slope) roofs. I have knowledge in the installation as well as the design of roofs from an engineering standpoint.


I have been doing roofing for 40 years. This was my father's business and I took it over in 1980.

I have written responses to artcles that I felt needed a response to and those responses have been published in roofing trade magazines.

BSEE Drexel University

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