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Deck pier inspection?

SCBO1

SCBO1

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Deck pier inspection query.

17" dia. piers have a few large rocks protruding in the pier sidewall about a third, notified contractor they need to be busted out, not much effort was used to remove the rock IMO.

Contractor sez "can't bust um out, it would take a jack hammer, would you require the rock to come out? or would you allow a pour with rock protruding through the pier side wall?

pc1
 
Without knowing your local soil conditions, it hard to say.

I'd think if the rock was big enough it could stay.

We don't have many rocks here, just clay and roots ;)
 
I wouldn't lose any sleep over it if they look solid, 17" is a heckuva pier.
 
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It doesn't sound like a structural issue so much as a visual one.

If the visual aspect is a concern, ...the rocks could be ground

down with a grinder to have a more uniform appearance of the

piers in question.

< + = +
 
What the heck kind of a deck are they building, that it needs a 17" pier? Around here I have to argue with every customer that they have to use a 6x6...
 
Typo, 12" pier. "Slow down on those energy drinks!" geez, I don't have the edit capability.

I'm OK with the rock, the majority of the concrete is at the base about 12" thick x 12" dia. But I asked that they try to bust the protruding rock, not much effort was put forward.

JC, I got the 6x6's, no issue there.

pc1
 
Keystone what is your authority for requiring a particular product be used?

The Bigfoot is for use with a bearing footing system and would be inappropriate if there was a need for a friction pile.

It is unclear regarding the size of the rocks and how they got there. If well integrated with the concrete the rocks may be no different than the aggregate in the concrete. On the other hand if the rocks were the result of caving excavation that resulted in soil being mixed with the pier then more extensive repairs may be required.
 
JCraver said:
What the heck kind of a deck are they building, that it needs a 17" pier? Around here I have to argue with every customer that they have to use a 6x6...
Click to expand...
Most piers need to be somewhere in that range. Not many 12" piers in assumed soil conditions of 1500 pdf.
 
Some might want to take a gander at the AWC deck construction guide and look at table #4 for footing and pier sizes, foot note 1 assumes 1,500 psf soil bearing as Jeff noted.

This project the pier is 36" deep and about 12-14" in diameter at the base and cones out at the top about 16-18" with the rock protruding into the sides of the pier.

I'm satisfied it meets code requirements
 
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Pcinspector1,

In your opinion, does the "protruding rocks" match the compressive strength

[ in psi ] of the concrete mix ?

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north star,

The rocks protruding into the pier are above the base pour of the pier (below frost) and are more of a nuisance, I just thought more effort could have been used like using a long handle "spudbar" or "stardrill" on the rocks? renting a jackhammer seems a bit over kill. The rocks may act as a wedge after the concrete is poured.

pc1
 
Mark K - Maybe I did not make my statement clear;

1. "with the base hollowed out SUCH AS", the last two words are key, that portion of the statement does not mandate the use of the Big Foot System is mearly an option to which I personally would be open to.

Friction pile, yes that is an option one which is infrequently seen in my area.
 
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All of the posts are sitting on pier blocks.... all of the pier blocks are sitting on dirt.



A neighbor turned them in for not having a permit. There's a lot more going on than just this deck.
 
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