Vinyl siding installed diagonally

Hi there,
I came across this vinyl siding and I have 2 concerns with it.
First: Can it generally be installed diagonally?
Second: The connection between the diagonal siding and the horizontal will probably leak, or what?

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No doubt there, I just hope they have a good sound WRB. Especially at that horizontal molding.

I just did a quick read over of: Vinyl Siding Institute 2018 installation guide and found no reference to diagonal installation.

You may have better luck but I don’t think it is, typically, made for that application, especially when one can see the cuts above the J channel.

I believe most manufacturers recommend it be installed only horizontally.

that’s got to be leaking already…

No kidding, Jim!

Wish I had pictures.
Back in the late 60’s and early 70’s, when 8" and 12" Masonite siding was going strong, there was a fad going on with the siding being installed in the same pattern as the OP’s picture.
Only a few builders did that and the fad did not last long, so it must of leaked too. :grinning:

I remember that!

The J-trim should have holes to drain and a Z flashing installed at the change of direction.


I like it!

I have installed alot of siding over the years and have never seen a manufacturer recommend horizontal siding be installed like that… This will definitely leak.

There will be water penetrating down behind the horizontal siding for sure🌨


Diagonal vinyl will not leak. It’s the directional change that will leak if not properly flashed (and that in the photo is not). Z flashing will work just as effectively as when it’s installed at the horizontal joints on T-111.