Looking at purchasing a home and have some concerns with the fiber cement siding condition and installation (I have no knowledge of this type of siding)

- House is 22 years old and i believe the siding is original
- My main concern is with the large gaps in the vertical butt joints that seems like it will let water infiltrate into the horizontal joint
- Also concerned with the minimal overlap on the horizontal joints highlighted in the last picture
- I have read that this fiber cement siding uses flashing behind the siding to prevent water infiltration so I want to make sure I am not over thinking it

Assuming you're going to have the house inspected before closing, the inspector should be able to give an informed opinion. I don't know how that kind of siding is supposed to work, but it does seem in the second picture that the top piece to the left has come loose from the house and the nail is not set.

Depending on how real estate contracts work in your area, if inspections find this is a substantial problem (and/or find others) during a due-diligence period specified in the purchase-and-sale contract, the buyer can ask the seller to fix them and if they don't, seller would have the option to back out of the sale.

Side comment: Having bought 5 houses, sold 4 of those, and having put offers on several others that were accepted but did not close, I will say that the odds are that a professional inspector will always find issues - some possibly major, but often a lot of trivial things. You can't expect a clean inspection on a real-world house - what matters to the buyer is how the seller responds if anything major is found.

Not sure how they did yours but I’ll tell you what we did.

About 15 years ago 3 of us decided to reside our houses as we were all capable carpenters. We used Nichiha fiber cement board. Same style. When installing, not only did we paint the ends but we made sure the butts were tight but we also put a small piece of tar paper under the butt joint.

Now I’m no siding professional so I can’t tell you if what you see is normal. The space bothers me because it is much larger that a heat/cold expansion/contraction. It might be fine but it would be good to hear from a pro.

My experience is that older Hardi installs were caulked at the butt lines, which usually meant recaulking as the seams opened. The current install is with a specific flashing or clips between butt joints leaving an air gap. Btw, the plant materials in your pic are way too close to the siding, should be trimmed back.

Thank guys, appreciate the insight.

My understanding was that cement board siding didn't need the gaps since it doesn't expand or contract like vinyl and aluminum does.

To me, it doesn't look like there is any flashing behind it. Looks like in the areas where there is a gap, moisture is free to get in the horizontal seam and the only thing that would prevent it from rotting the wall sheathing would be the house wrap behind the siding.

Hoping someone knows what how the flashing would be installed and can tell by the pics if it is or not.


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Good morning from Europe. We are on vacation.

My company had installed literally miles of fiber cement siding. It is a great product….when applied correctly.

Over the years since its introduction in the 80’s the methodology for properly installing it has evolved. Initially, the butt joints were applied tight then just painted over. Then it was ok to have a small gap which was then to be caulked by the painters and over the last 10 or 15 years or so a piece of flashing was to be applied behind the but joints to allow the wall structure to breath. This results in very small cracks at the but joints but dramatically improves the performance of the wall system, particularly with today’s houses which are built very tightly.

Here is the official instructions from James Hardie, the original manufacturer. There are other brands but they are all the same.

https://downloads.ctfassets.ne...eplank-hz5-us-en.pdf

quote:

Originally posted by smlsig:
Good morning from Europe. We are on vacation.

My company had installed literally miles of fiber cement siding. It is a great product….when applied correctly.

Over the years since its introduction in the 80’s the methodology for properly installing it has evolved. Initially, the butt joints were applied tight then just painted over. Then it was ok to have a small gap which was then to be caulked by the painters and over the last 10 or 15 years or so a piece of flashing was to be applied behind the but joints to allow the wall structure to breath. This results in very small cracks at the but joints but dramatically improves the performance of the wall system, particularly with today’s houses which are built very tightly.

Here is the official instructions from James Hardie, the original manufacturer. There are other brands but they are all the same.

https://downloads.ctfassets.ne...eplank-hz5-us-en.pdf

Thank you for posting while on your vacation!

This is very helpful, it shows that it requires 1.250" of overlap which leads me to believe there is indeed flashing behind that joint. The bottom edge of the flashing behind the butt joint is what I was erroneously thinking was the top of the next siding piece.

I will verify this when I am there next but I think there are no major install issues that would lead to water infiltration (other than that half-ass piece under the window).

Thanks for everyone's help!


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