Help! Casings around window with integrated J channel?
OP says he has windows with the J-channel built in for Vinyl Siding and now wants to install Hardi and is concerned because you can’t get into the channel to properly caulk.
His solution is to trim the window and butt the siding to the trim so it can be properly caulked, that’s great.
My concern is that the 5/4 trim he wants to use is only 1” thick. OP says (if I’m understanding correctly) that still leaves him with 3/16” gap showing in the channel and is that acceptable to caulk.
What I’m saying is no. Rather than trying to caulk the 3/16” gap of the channel (and wasting a lot of caulk as the cavern try’s to fill up) the thing to do is install thicker window trim (1 ½”) so it completely caps the channel and then now stands proud of the window ¼”+. Now the channel of the window is capped and you can caulk the trim to the face of the window and the siding to the trim.
I personally don’t like 5/4 trim for new windows. Most new construction windows protrude 1 ¼” out from the nail flange and after installing "30lb ASTM Felt, blind caulked" (or whatever you choose) over the flange the 5/4 trim the trim comes out flush to the face of the window leaving no acceptable offset for a proper caulking job. 5/4 for corners, OK.
All of that said, OP said he originally was going with Vinyl Siding when ordering the windows and then after the windows were in decided to go with Hardi. If he had stayed to the original plan and go with Vinyl Siding what would keep the water from getting behind it?
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Last edited by kwikfishron; 05-31-2010 at 08:51 PM.