CertainTeed double talk on fiber cement siding

[Mike Lamb]

Hardie fiber cement siding does not want butt ends caulked.

Ceratinteed does not either and says so in bold at a couple places in their instructions like they really mean it. And then they offer this:

If the architect, designer, installer, project manager,

contractor, property owner, code official or other entity

involved with determining the method of installation

on a project determines that spacing the butt joints

and applying caulk is an acceptable practice during

installation, such practice will not affect the eligibility

of the WeatherBoards Fiber Cement siding product

installed on the project for warranty coverage with

regards to product defect, provided that the caulking of

the butt joints does not inflict, cause, or otherwise create

a condition where this practice was, is, or becomes

the cause of product failure.

I know it is a statement to please everyone. My question is why is it so bad to caulk the butt end gaps other than cosmetic?

[Jim Katen]

. . . I know it is a statement to please everyone. My question is why is it so bad to caulk the butt end gaps other than cosmetic?

It's bad to caulk the butt joints because the caulk always fails and allows water to track on the building paper or whatever is behind the siding. It doesn't harm the siding.

I don't see the statement as double talk. They're allowing that someone might want to install caulked joints - perhaps to match an existing installation - and they're saying that such an installation won't void the warranty. Nothing wrong with that.

[Mike Lamb]

. . . I know it is a statement to please everyone. My question is why is it so bad to caulk the butt end gaps other than cosmetic?

It's bad to caulk the butt joints because the caulk always fails and allows water to track on the building paper or whatever is behind the siding. It doesn't harm the siding.

I don't see the statement as double talk. They're allowing that someone might want to install caulked joints - perhaps to match an existing installation - and they're saying that such an installation won't void the warranty. Nothing wrong with that.

Right. They are saying don't caulk the joints in bold. They don't want the siding butt joints caulked. You get the impression caulking is bad.

Then they say, okay, you can do it pretty much the way anybody says if, ...the architect, designer, installer, project manager, contractor, property owner..., baby sitter, mother-in law, says its an acceptable practice. Then its all good, as long as ... the caulking of

the butt joints does not inflict, cause, or otherwise create

a condition where this practice was, is, or becomes

the cause of product failure...

Then we are not OK with this.

That's sounds like double talk.

[Mike Lamb]

This particular job had flashing behind all the butt joints. That's a good thing. But the instructions say there should be no gaps at the butt joints. This job had some 1/4" gaps at the butt joints.

From Cert. Butt end/joints should be installed with factory-sealed or factory-prefinished ends butted together in moderate contact. And then in bold: NOTE: It is never acceptable to leave a gap of any size at a butt end/joint.

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I don't see 1/4" gaps as a problem but again, the instructions seem adamant. Bolds seem adamant. And then they get all spongy that they don't really mean what they say unless something bad happens.

If the manufacturer can't commit to how their product should be installed it makes it harder on the HI. I have to make the same doofus fudging they do.

[Jim Katen]

Maybe you should write a stern letter to the company.

[Mike Lamb]

Yes. Something strongly worded should do the trick.

[Tom Raymond]

Make it a bold statement.