New home's floors are sagging: Blame all those Pier shims?

Today I inspected a 11th month warranty inspection. They called me because they have seen so many issues already with the home, the worst of which is drywall cracks in the corners of interior doorways and difficulty operating those doors due to the racking of the door frames.

In the crawlspace I see what I suspect may be a contributing factor. Stacks of softwood shims and the top shims are sometimes only an inch wide, not 2x6 full size pieces.

I know that for mobile homes, no more than 2" of wood is allowed for shims on top of concrete or CMU piers. Are the rules the same for stick built homes? I’ve been searching for codes and can’t find any limits. Here are some hot pics of the crawl space. Please let me know if you know the limit for shim stack height on stick built residential.

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If it were a mobile home, I’d use HUD’s standards.

Well that beam is not plum and will be susceptible to rotation. Those are no longer shims, they are piers IMO, and the supports are now posts atop a pier. I think post must be solid minimum 4x4 nominal.

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Which code are you operating under? TN 2012? Nashville? I am trying to figure out your dang state :wink:

So here is the 4x4 requirement

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thanks, Brian. that helps quite a bit.

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That’s quite a mess for a new house. As an HI with an unhappy/angry buyer (at the builder) I’d be quick to remind them that our purpose is to identify the “what” not the “why”. Of course, we all all dig into the why, how, when, where because we’re curious and it ultimately makes us more educated and better inspectors. But, at the end of the day, your job is done when you show the end performance problem.


Good Point, Matt. I’m allowed to stay in my lane. I don’t have to tell the builder how to fix it.

This builder usually does high quality work. I was surprised to see the tall stacks of yellow pine shims (soft wood) on top of those CMU piers.


@sbridges2 I agree…but I think squash blocks may be a design element determined by the engineer or manufacturer. I need to go down that rabbit hole again. I was telling Bert I had a similar experience as this home. In my opinion squash blocks would have proactively prevented the issue (top and bottom cord of the i-joist had split which is hard to detect)

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Nice catch, Scott. I’m going to recommend Squash Blocks even if there is little chance they will be installed.

Typical new construction sh!tshow.

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Squash blocks are usually required when there is a support wall above, check with the joist manufacturer.

True, but if piers are necessary, there is a load path of some sort, thus the need for the squash blocks.