Cement Fiber Butt Joints

[Snipe Hunter]

I installed Fiber Cement on my house in 2002 after my vinal siding was holed during a hail storm. At that time they said to chauk the joint with some flashing behind it.  The issue I have is I painted mine. Overtime the joints expand and the paint cracks. So far I still have the original paint job I did so I have not touched it. If I did it again, I would flash behind the joint, paint it, then use a clear chaulk that would not be painted.

You can buy painted flashing on a roll.

I did an inspection this week and saw these H-Channels on fiber-cement siding. I may have seen it before and just not paid any attention to it. The whole neighborhood had it. Low and Behold... Some of them were missing.

[vernonator]

Our current house was built in '22/'23 (moved in Sept 23) it has fiber cement (Hardy Plank) and the butt joints were flashed and NOT caulked. I asked the installers about it, and told them about our old H-channels. They said that was how they were done back then per Hardy. Now the manufacturer says butt joints are flashed, sealed with provided primer if cut, and no caulk - leave them open to allow any moisture that gets back there out.