# Slab Prep.



## tgeb (Feb 9, 2006)

We have been working on a detached garage addition.
Hit poor soils and had a geo-tech look it over, recommended undercutting the entire area.

Then decided to check with a structural engineer and ended up with a structural slab, bearing on footings down to suitable subgrade. 

We are preped for the first section of slab pour.


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## Moxley-Kidwell (Jan 28, 2011)

Looks good. Is it easier or cheaper to do the structural slab? Only real concrete I ever deal with are mostly curb and sidewalk with the occasional abutment or something small. Guess the bad soil was pretty deep? 

We're just finishing up some block retaining walls off shady grove road in a small park that we ran into some real pia fill that whoever did had topsoil and anything you can think of in it. Fought the weather and bad dirt for couple months trying to finish these things. Pretty much ended up rebuilding the hillside with stone to get them done.


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## griz (Nov 26, 2009)

Nice job, looks good...

Just surprised to see visqueen rather than a commercial vapor barrier.


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## tgeb (Feb 9, 2006)

Moxley-Kidwell said:


> Looks good. Is it easier or cheaper to do the structural slab? Only real concrete I ever deal with are mostly curb and sidewalk with the occasional abutment or something small. Guess the bad soil was pretty deep?
> 
> We're just finishing up some block retaining walls off shady grove road in a small park that we ran into some real pia fill that whoever did had topsoil and anything you can think of in it. Fought the weather and bad dirt for couple months trying to finish these things. Pretty much ended up rebuilding the hillside with stone to get them done.


The pics only show a small portion of the project, we are doing it in 2 phases due to the design. This is a garage with an "in-law suite" above, the photos are of the level slab area that will accommodate the stairs to the second floor and a utility area below the stairs. 
Phase 2 will be the actual slab of the garage (with grade beam, and reinforcement), sloped to the door.

We had a geo-tech come out when we hit poor soil. he recommended going a little deeper with the footings to good soil, which is about 3'-6" and our planned elevation was 30" so that was not too big of a deal.

He wanted us to install the footings, then dig out all of the poor soil inside the footprint of the building. We would then bring in suitable fill and compact, or simply run in some 57 stone to bring it back up to grade. 57 stone was the best option since we did not have to compact and test it as it went back in.

We thought it might be less expensive to do a structural slab as opposed to exporting, then importing all that material. We had the structural engineer that had already designed and stamped the building plans look at it, give us a design, and we ran the numbers between the 2 options.

The structural slab ended up being about 1/2 of what it would have cost to remove and replace the bad soil with stone. :clap:

I like to save clients money when I can. :thumbsup:

I'll post some additional pics as we go along.


PS. I didn't know you traveled this far South, Shady Grove is south to me....we'll have to buy each other lunch one day.


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## tgeb (Feb 9, 2006)

griz said:


> Nice job, looks good...
> 
> Just surprised to see visqueen rather than a commercial vapor barrier.


Thanks, Griz, I'm not sure what a commercial vapor barrier is, this as well as most of the projects around here, call for 6 mil poly.

I have seen one or two that I have priced out that called for 10 mil poly but I did not get those...


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## cdkyle (Jul 12, 2009)

Looks good. Order the mud. :thumbup:


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## slowsol (Aug 27, 2005)

tgeb said:


> Thanks, Griz, I'm not sure what a commercial vapor barrier is, this as well as most of the projects around here, call for 6 mil poly. I have seen one or two that I have priced out that called for 10 mil poly but I did not get those...


I'd guess he means Stego. It's 10mil with reinforcement threads.


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## cdkyle (Jul 12, 2009)

Not to hijack your post, but here is one we poured today.


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## tgeb (Feb 9, 2006)

I don't mind the hijack, That looks good, a lot of steel in there.


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## dayexco (Mar 4, 2006)

not picking anything apart here, but over the years, i've seen OSHA inspectors turn their heads to building/basement excavations that are 10'-12' deep, straight excavation walls, walk over to side of same project, see the utility contractor putting in a 6' deep utility, and nail him for improper slope/shoring....many, many times.


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## slowsol (Aug 27, 2005)

dayexco said:


> not picking anything apart here, but over the years, i've seen OSHA inspectors turn their heads to building/basement excavations that are 10'-12' deep, straight excavation walls, walk over to side of same project, see the utility contractor putting in a 6' deep utility, and nail him for improper slope/shoring....many, many times.


That is a hell of a vertical cut! But the work looks neat and clean!:thumbsup:


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## cdkyle (Jul 12, 2009)

dayexco said:


> not picking anything apart here, but over the years, i've seen OSHA inspectors turn their heads to building/basement excavations that are 10'-12' deep, straight excavation walls, walk over to side of same project, see the utility contractor putting in a 6' deep utility, and nail him for improper slope/shoring....many, many times.


I know, I've been a nervous wreck. Although, we are right up against the property line. The only way to have done a step cut, was to cut into the street, which is on two sides of the big hole.


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## rino1494 (Jan 31, 2006)

Wow, seeing that guy kneeling down right next to a 10' vertical excavation makes me cringe. Should have done some shoring. One good rain storm and somebody is going to earn their PHD (pine handle degree).


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## rino1494 (Jan 31, 2006)

BTW....nice work Tom. How are the customers handling the additional costs ?


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## tgeb (Feb 9, 2006)

rino1494 said:


> BTW....nice work Tom. How are the customers handling the additional costs ?


They are obviously not thrilled to be spending more money, but they are realistic and understand the situation, so, all is good.

In fact they were on board with the first estimate to R&R the material at a higher cost, I'm glad we came up with a less expensive alternative....They are too.


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## rino1494 (Jan 31, 2006)

Is this a job that you bid? Did you have a clause in your contract for unsuitable materials ?


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## slowsol (Aug 27, 2005)

cdkyle said:


> I know, I've been a nervous wreck. Although, we are right up against the property line. The only way to have done a step cut, was to cut into the street, which is on two sides of the big hole.


ERS. That's how I would have bid it.


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## tgeb (Feb 9, 2006)

rino1494 said:


> Is this a job that you bid? Did you have a clause in your contract for unsuitable materials ?


Yes, I do have an unforeseen clause in my proposals. 

Rock, poor soils, tree stumps, abandoned structures....the list goes on...
Seems like every project brings up new things to exclude.


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## slowsol (Aug 27, 2005)

tgeb said:


> Yes, I do have an unforeseen clause in my proposals.
> 
> Rock, poor soils, tree stumps, abandoned structures....the list goes on...
> Seems like every project brings up new things to exclude.


Excavation is an easy trade to get screwed on. I hear ya!:thumbup:


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## Moxley-Kidwell (Jan 28, 2011)

Hey Tom,

Shady Grove is a little south for us, but not too bad. Try to cut it off before we get into Bethesda, D.C. and PG County when we can. We've been spoiled the last few years to work mostly in Clarksburg, Urbana, Poolesville and Frederick. This one is for a real good Super that we used to do work for and has gotten a new job with Toll Brothers land development side. Great guy to work with and he is trying to finish up a job someone else started. He's also got us working in Olney and will be moving back into Clarksburg in the next year or so.

I think you went it the right direction not undercutting though, such a pia trying to get rid of spoils in Montgomery county. I'm used to being able to undercut and just get rid of the spoils on site can't imagine trying to get anything done on those smaller residential sites.

I'm down for lunch some time, I get cross eyed just looking at plans all day sometimes. I'll usually try to get out on the job for a little bit and grab a shovel or something just so the guys don't bust my balls too much.


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