Footing Excavation

ConcreteGuy

I recently employed a grading contractor to dig my footings and I was wondering if any of you earth movers have tried it.

The things he did not understand in moving from Division 2 to Division 3 were slowly learned, and to be honest, I still don't think he gets it.

The difference between the two is accuracy and speed. You have to go from a tenth of a foot in sitework to a quarter of an inch in footings, and from having little coordination with other trades, to having formwork, rebar and concrete placement contractors breathing down your neck.

I think we made a mistake in expecting a grading contractor to perform this work. To me it is as different as moving from residential to commercial contracting, and vice versa.

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A reasonable expectation becomes an assumption when it goes wrong.

dayexco

i think a 1/4" tolerance in footing excavation is a little demanding....

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someday, i'll be as patient as Nick.

jmic

Concreteguy,
I fail to see what your point is, so I'll ask, Whats your point?

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Joe

denick

What type of work and footings are you reffering to?

We have a very diverse group of people that would reply just need a little more information why there is the need for that accuracy in the excavation.

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Nick

"Every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving" Albert Einstein

Tscarborough

I have never seen 1/4" accuracy with a shovel.

rino1494

Yeah, just as long as you get them within 1-2 inches that is great.

I do have to agree, hiring a person that only is a grading contractor may not work because he isn't well rounded in the excavation field, but I am sure he will get it.

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TMatt142

MORE INFO NEEDED! What are you doing, footings for houses?? We need to know that, although I've done commercial footing digs, and residential. Didn't really see a difference. As far as 1/4" tolerance, Not even state highway depts require that close of a tolerance on their roads!! If the operator did a bad job, then I think it was more of an issue with his skills. Did you explain to him that you wanted it on the knats behind??

dayexco

i've been reading all these posts on tolerances. and can see that the post i made in response to concreteguys probably took this topic way off what he intended. i still feel that 1/4" tolerance is very demanding. BUT, if in the specifications handed to and accepted by the digging contractor called for 1/4" tolerance, that's what he'd better provide. if it means hand shovelin the last bit down to that point, so be it. he'll just have to adjust his excavating bid to compensate for the additional time spent. it's not fair for the concrete crew to either trim the excavation down to the proper depth, or buy the additional concrete if the agreement was for a 1/4" tolerance. he'll pay dearly for that tolerance because of the production lost by the excavator. we always strive to be "right on", and i'd say that most of ours fall within the 1/2"-3/4" range. the concrete guys here tell us they'd much rather be 1/2" low, than a 1/2" high, easier to put in a little more concrete than spend time trimming the hole out by hand.

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someday, i'll be as patient as Nick.

ConcreteGuy

There is a difference. If you put out an ad for a lever puller to lay pipe, you have production and accuracy expectations that differ from a footing contractor. Neither one is better, just different.

The tolerance differences are from a surveying standpoint, and it is the only way I know to quantify the difference. Granted, if you are an operator, you simply follow instructions and dig, but earthwork contractors are unfamiliar with the precision and tightness required by foundation work, especially with concrete having nearly doubled in price over the last five years. A quarter of an inch is a mindset, not a reality. And over excavation is a sin punished by firing. And Dayexco's got it right, it's labor intensive hand trimming.

The analogy of an inch given becoming a mile is grossly exagerated but based in truth about human nature you can't overcome. And so a tenth of a foot gets a little sloppy, just like a quarter of an inch. And so a tenth of a foot or a quarter of an inch become a guideline, not a rule.

Questioning the point of my observation is validated by most of the responses. It confirms what I suspected. Division 2 excavators are not suited to move into Division 3 footing excavation, and why should they be? One of my guys would never make it with your crowd either. He would look across the site and see no painted or chalked lines and freak out.

Again, a quarter of a mile, or a tenth of a second, or however you measure and quantify performance is all based upon expedience and experience.

We played Dr. Frankenstein and failed.

Uh, the guys we used have happily moved on to what they do best...Sitework.

Thanks for the input,
and stop running over the surveyor's stakes!

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A reasonable expectation becomes an assumption when it goes wrong.

dayexco

you know, we can't get that kinda weed out here in the dakotas

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someday, i'll be as patient as Nick.