Window trim overlapping hardiplank

I inspected a new construction home and it had windows installed with the trim overlapping the Hardiplank.with gaps all along the side and bottom. The siding is blind nailed, and loose at the bottom.
I know the siding has Tyvek under it. But is it not losing energy at all of the gaps? Is this considered ok?
I would recommend installing the siding butting it up to the side of the trim and caulking all of the vertical and horizontal gaps.
What is acceptable to code? The Hardiplank PDF says not to caulk anything, but in the same PDF,

it says to use elastomeric or latex caulk at the bottom.
Please help.
Thanks, Mark

If there are gaps, they should be caulked to prevent water intrusion.

Nope, not OK. Download the manufacturer’s instructions. With HardiPlank no trim should overlap siding anywhere on the house. The instructions are very specific about that and about the the gap size left between siding and trim and how it is caulked. There’s no guessing about this.

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(assuming it’s Hardie Brand siding product)


Thank You for your help. I submitted the report and my client is thankful as well.
God bless.
Mark Fix

Also, it’s not shown here, but the Installation instructions call for inside corners to have housewrap, and 90 degree sheet metal (3" or 4" flanges) installed in the corner behind the corner trim. Don’t expect to actually see it, though. I’ve never seen a set of installation instructions on an actual job.

Also, the instructions call for ¼" gaps to be left above window and door head flashing and these gaps should NOT be caulked, so that any water getting behind the siding can find a way out. Kinda looks like they are caulked in your photo.

I did a lot of research on HardiPlank for the House of Horrors in order to make sure that the example that was supposed to be correct was actually correct. I gave the instructions to the installer. He installed the trim around the window OK, but then he butted the siding tight to the trim. This stuff is installed wrong all the time.

Thank you. I think it would be a good idea for internachi to make a course on the correct instalation of hardiplank.

There’s a station at both Houses of Horrors (Boulder, CO and Weston, FL) on it.

5. JAMES HARDIEPLANK.docx (106.5 KB)

Unless the installation is in product zone HZ10. Outside corners are allowed to be trim over siding.

This little guy is buried in the bottom left corner of page 49.

In my area, 50% of homes with Hardie incorrectly have ALL the trim over siding.
…and butt joints at top/bottom of window
…and no flashing at horizontal surfaces
…and no flashing at penetrations
…and no flashing at masonry

Brandon, does HZ stand for Hurricane Zone and 10 is a wind speed designation? Thanks for pointing that out!

No, its simply a regional designation by the company for product use & installation procedures. There is an installation manual for both zones. (HZ5 & HZ10)
Inspectors should make sure they refer to the proper manual per the zone they are in.

Hi, Reading through this post, really interesting discussion BTW, I didn’t see it mentioned but the problem seems to be the windows are designed to receive vinyl siding. (This would have been an option that the builder would have selected not likely to change the price any) basically the window has a J channel built in I have seen guys glue a piece of Azak into this channel to accommodate dimensional siding.

Improper material selection on the builders part. Though the builder will likely make the siding or window guys take the fall for it.

Hello Arthur,
I talked to the builder, and he said that these are silver line windows and they are designed for any kind of siding. I told him that according to the Hardy website this is incorrect. I asked him to send the client proof that it was acceptable. I told him I inspect and report. I am not here to argue.
Thanks for your interest.
Sincerely , Mark Fix

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