Hardie Plank Between Sill Plates

[CNewhouse]

I inspected a new home today. On top of the pressure treated 2x6 sill plate there were 4 additional 2x6 plates (presumably to get the sill plate up to the height of the floor system).  Between 2 of these additional 2x6 plates, there was a continuous run of Hardie plank siding, used as a shim/spacer. This was a 2 story home with composite roofing (a substantial load was being transferred through the Hardie). I'm curious what others think of the fiber cement siding installed here and how they'd comment in their report.

Additionally, any ideas why the builder would pour the foundation low and build up the sill to meet the floor joists? 

[Mike Lamb]

From HardiePlank installation instructions:  • HardiePlank lap siding may be installed on flat vertical wall applications only.

I would remark in the report that this product is not supposed to be used this way and you cannot predict if this will cause future problems.
 

[CNewhouse]

That's basically what I said, in addition to including a comment from Hardie, "You cannot use our products as shims. Our products are not designed, tested or warranted for this type of application".

The part I was a bit hung up on was what recommendation to make to the buyer. This is wrong, here is why, and... what? Ask the builder for documentation that this is an appropriate use of Hardie? They won't have that. Consult an engineer? They won't do that. I try not to kick the can down the road, but I wasn't sure how to avoid it here.

[Marc]

Is this a seismic area?

[Mike Lamb]

How about something like,

"This product is not supposed to be used this way and I cannot predict if this will cause future problems.  The seller should provide documentation from a qualified source that the use of this product, as used, will not be a future structural concern."   I would also include the Hardie references in the report.

[CNewhouse]

1 hour ago, Marc said:

Is this a seismic area?

Yes. That was another one of my concerns. The anchor bolts only secure the lowest PT sill plate to the foundation. Even with shear panels on the exterior wall, I would think that the strength of the connection between the foundation and framing has been compromised. 

[Jim Baird]

It looks thicker than lap siding to me, more like the cornerboard stuff they make.

Even so, product is not listed for the use.  Looks like no way to practically correct.  Is it a custom home?  Signs like this tell us there may be plenty of other problems with wrongly applied product.

I would tell buyer this is a big red flag, fairly describable as a structural defect.

Don't walk away, run.

 

Why did he do it?  Likely just an early layout screwup.  Sign of an amateur maybe.

Edited January 15, 2020 by Jim Baird
Sp

[Jim Katen]

The builder mistakenly built the stem wall too short. 

Whether Hardi allows it or not, the shims will be fine as long as gravity is the only force acting on them. 

My only concern would be how the whole assembly will hold together during an earthquake, and that would be a significant concern. There's no way to know that without knowing how the builder connected all those pieces together. 

If I was in a bad mood, I'd recommend that the builder re-build it to comply with the approved plans or, alternatively, hire an engineer to ensure that the existing construction will provide equivalent seismic performance.