Installing Hardi Plank Siding Around Windows W/ J Channel

brownie77

Has anybody ever installed Hardi plank siding around windows with j-channel attached? The J-channel measures 3/4", and the hardi plank is 5/16" or overlapped 5/8".

house bldr

It can be done but you need to flash up under the window and out over the next row of siding under the window to shed any water that gets in around the window flange. BUT, it isn't the best way to do it because you are leaving cut edges exposed to the weather!

tinner666

I second the opinion. I prime those edges. Since I'm a roofer and go for overkill, I also use tapered step-flashing with each piece of siding and install a metal dripcap on the top, weaved into the siding.
The way I've been doing it. the snap-on brickmold will still snap on, but I then put the dripcap above it, at the top.

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Frank Slate Roof Repairs, Richmond, Va.

losthenfound

Never !!!!!!

A W Smith

so how do you install hardiplank around a window that already has an integral J channel? Cut off the head channel and install a drip cap?

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Al Smith
http://www.awsmith.com

curapa

I would ad 1x4 hardi to trim the window out. If the window channel is 3/4" you should be able to slide pieces behind it. Caulk the inside of the chanel then slide in your 1x's.

neolitic

Better yet, Azek 1X4's (or ripped 1X6).
Just make sure your flashing is wide enough for the job.
Sounds like someone ordered the wrong windows though.

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(Sorry....it seems there really are dumb questions)

dkillianjr

Yup thats what I have done in the past, it worked great .And lokked a lot better too.

Dave

losthenfound

There are a number of ways of doing the job correctly. First try to eliminate the J channel. Either spec a different window of buy new ones. You can but and adjoining pc of trim to the perimeter. Bottom line – don’t use a J. Don’t caulk inside of a J. That is like putting your finger onto a water hose. Lateral gushers form from the fissures when the caulk dries.

Proper head flashing and NO J CHANNEL -EVER
with J Channel:


with watershed head flashing:


Then you can look over tinner666's page (very informative - see pics)