Monolithic Slab - Should I be worried about ...

[mrbond]

A builder is building a 2 story, all brick garage/workshop/pool house--whatever you want to call it. The foundation is a monolithic slab, with footers. This is in the Middle Tennessee area.

The builder dug the footers. And put up formers along the edge of the footers. On the outside of the footers, where the concrete spills over from the footers as it hits the bottom of the former--that is what he wants to use as a brick ledge.

This brick ledge in some places could be as little as 2-3 inches deep. It won't be consistent. It's basically a "muffin top" of excess concrete from the footer. It's not squarely on the footer (see diagram).

Not surprisingly, this does not pass codes where I live, if it were an inhabited structure. Surprisingly, though, this does pass codes if the structure is uninhabited!?

The codes inspector told me that this footer might give way over time, probably within a few years, maybe sooner, since its 2 stories of brick--or it may not. It's questionable at best, and that's why it wouldn't pass codes if it were inhabited.

Is it any wonder people outside the south make fun of people in the south?! I seriously can't believe I'm having to argue with a builder about this. (And yeah I'm from the south, so I can say that...).

 

[willymakeit]

It will probably crack at the change in thickness. Not for me.

 

[brownbagg]

no, not a problem

 

[C96]

Unless I’m missing something, there sure looks to be something wrong here. Are you sure this is the intent of the builder?

What does the foundation detail show on the plans?

Maybe you can post some pictures of the foundation detail and what has actually been done so far.

 

[Big Bad Dad]

Wont pass code as far as I know. "Inhabited structure"? Bottom line, who is paying for it? You? STOP them NOW!!! You are about to own an ongoing problem.

 

[lilcuda]

I agree with C96. How is it drawn on the plans? If the builder wants to do it differently than the plans, don''t let him. If he won't do it per the plans, tell him to pack his stuff and go and get someone who will do it right.

I had a garage built 9 years ago (I have since sold the house). The foundation was drawn as a footer with a separate slab on top of the footer. The contractor poured it as a monolithic slab, including footers. It cracked a lot. The only reason it stayed together was the massive amounts of rebar. I should have fired the guy before he poured it, but I figured he knew what he was doing. He did it that way because it was easy. I know that now.

Just remember, YOU are writing the checks and YOU are the boss, no one else is, especially the builder.

 

[2drx4]

It sounds to me like he screwed it up and is just 'going to make it work.' And it isn't going to work...

 

[KANSASBOY]

I me it's to thin lots of weight will be on it . http://softplantuts.com/Forum/SoftPlan/SoftPlan/Monolithic-Slabs

 

[Bib Overalls]

Just say no.

 

[dirttracker18]

I am not sure why he would just form a correct ledge for the brick.

For me personally, I don't think it is adequate long term. It also seems the inspector feels the same. Two stories of brick is a lot of weight to be supported by an overhanging ledge of concrete.

 

[Falcon67]

I'm not an expert but just about all new houses here have brick exterior and I've never seen any forms that did not include the brick ledge. None at all like what you describe. Do it right or don't do it. Bricks can expand and contract enough to crack mono slabs at the corners. Not counting the weight of a full wall of brick. The outer edge of the footer should be vertical with the ledge formed on top so the brick weight can bear down on the whole footer. Brick ledges here are usually made with a 2x6.

http://www.contractortalk.com/f83/forming-brick-ledge-91635/

 

[Grimpala]

Are you sure he isn't talking about using the edge that is left when the form is removed? That will leave a void that should be plenty strong to support brick.

How we typically do it is to use a 2x6 or bigger for the form and then attach a 2x4 or 1x6 flat to the inside edge of the form depending on the application.

What is he using to form the slab? If its a 2x4 or 2x6 I see no problem, other than the brick ledge being too shallow. Should typically be 4" to support a 3 5/8" brick.

 

[gayler]

I know a guy that lived in a bricked house with no brick ledge. After a couple of years he had electrical problems. He would loose one leg at times. A couple months later he had a major water leak. It turns out the brick settled and cut through the electric lines and the water line!

 

[mrbond]

Thanks for all the replies guys.

Here's a picture, showing that they dug out on the outside of the former (after I complained).

Aren't we really using left over concrete for a brick ledge? How will it be level? Won't the former vertical supports leave a void in what will be the brick ledge?

 

[mrbond]

Here's a couple of more pictures. Notice how the forms are uneven here, yielding an uneven brick ledge on the outside of the forms?

 

[Mechtech]

Why is there grass under you slab base rock? From what little I know about concrete work I'm going to say that the brick ledge is going to be the least of your problems down the road. With nothing compacted and organic material underneath it all the slab will break up almost instantly. (again based on my very limited knowledge)

 

[mrbond]

Why is there grass under you slab base rock? From what little I know about concrete work I'm going to say that the brick ledge is going to be the least of your problems down the road. With nothing compacted and organic material underneath it all the slab will break up almost instantly. (again based on my very limited knowledge)

For whatever reason, they left a two inch strip of grass on that side of the footer. It should have been removed, imo.

 

[tlmartin84]

What they have dug appears to be fine for the brick ledge. I am concerned with the grass under the slab, the topsoil should have been stripped. It will decay and allow a hollow spot under the floor.

There should be rebar coming out of the footer and tying into the floor mat if this is a true monolithic slab.

It also appears shallow, I would expect your frost line to be at least 24" (you should confirm that as well).

 

[mrbond]

The gravel base is also a little troubling. They are using gravel to level the site. So on the shallow end, there's 4-5 inches, the standard in this area. But at the other end, there's 10 inches. And the builder claims that the bobcat driving over it is good enough compaction. They didn't compact it as they went, in the deeper area.

I obviously picked the wrong builder, and hope this can be resolved without legal action.

 

[mtmgtz]

Here's a couple of more pictures. Notice how the forms are uneven here, yielding an uneven brick ledge on the outside of the forms?

I dunno what the heck this guy is thinking but your brick ledge should be 4" wide and continue to the bottom of your footer. So if you had a 6" footer your total footer width would be 10" with the 4" brick ledge. You want an air gap for drainage between your brick and framing.

Looks like a cobbled together mess.

 

[ACDNate]

Do you know of any other concrete finishers in the area? I would try to find one and see if you can hire him/her to come do an evaluation of whats there and give you an opinion. I'd offer them a hundo or so just for their time and opinion. Let them know up front that you aren't going to give them the job just pay them for their professional opinion. Take what they say to your contractor.

There are a handful of things that concern me with what the pics show, as mentioned by others.

Am I looking at bags of gravel underneath a thin layer of loose gravel?

 

[dirttracker18]

IMHO

I would stop everything right now. That is a hacked up mess on so many levels, never mind the problem with a lack of proper brick ledge.

Perhaps they do things differently there but my inspector would never let that fly nor would I accept that from my builder. That looks like **** compared to the prep for my mono pad and I didn't have brick to worry about.

Stop the work and get some opinions from trusted local contractors.

 

[steel 35]

Just say no.

 

[Morrison]

Is this the same contractor that did the "New garage very disappointed" thread?

Good luck sir, I would stop everything before it gets worse.

 

[tlmartin84]

So you are going to finish the slab and stud your wall up right on top of it? Then face it off with brick? Was that the plan?

 

[tlmartin84]

If I was in your shoes I would do this:

Pull the rebar and save it. Dig footing down to whatever code recommends, in WV it is 30". If it is a single story building you need a 12" wide x 6" thick footing with the rebar.

Scrape the 57's off, (Clean rock will tighten up with a vibra-plate but it will not "compact", so dumping it as he did was actually OK.

Bring in a block guy, and run a row of 12" block for your brick ledge. Then a couple of 8" rows to get you out of the ground. Install your expansion material and backfill with the clean stone, plastic, mesh or rebar (I prefer rebar on a minimum of 2' centers). Then pour the concrete at least 4" thick.

That's how I would handle it. I would tell the guy to leave and he isn't getting a dime other than for what materials he has purchased that you can reuse.

 

[CanadaBoy]

Not they would allow this usually here but this is how its done north of us. Btw, your inspector will fail the grass under there as well. No organic material!

Btw, the way they did it there is frost protected shallow foundation but picture yours without the foam.

 

[tlmartin84]

his will still require the foam insulation.

 

[jwhcars]

This sure would not suit me .... I would fire the guy before he pours the slab.

 

[GYPSY400]

This sure would not suit me .... I would fire the guy before he pours the slab.

I agree! This is the worst slab prep I've ever seen.. Listen to what others have said, and stop work immediately !
You shouldn't see grass where cement goes .. And the sandbags ??!! What's up with that??
The rebar should be beefed up too, but that could be a regional thing.. I have A LOT more than that in my slab.

It's pretty clear this builder has no clue


Sent from my iPhone using Tapatalk

 

[Elmo77166]

Fire him! He can't even be bothered to use form pins. The trench isn't even a uniform width.

 

[starquestMM]

. And the builder claims that the bobcat driving over it is good enough compaction.

That looks like a 1" clean material. "clean" gravels and crushed stone get 90% compaction just by gravity placement. If they compacted the **** out of it they could have gotten it up to 95% (maybe).

Thats the benefit of using clean gravel is that it doesn't usually need compaction. The downside is that if it is directly up against dirt, the dirt can move into the gravel over time which means settling. A separation fabric should be used in that case or some intermediate sized aggregate that meets the D10/D50 infiltration calcs.

 

[lilcuda]

As others have said, stop all work now. I 'm a layman, but I can spot horrible work. Take a look at how my former garage was built. Pages 2 and 3 have most of the detailed pictures of the slab forms, rebar, etc.

http://home.earthlink.net/~lae4503/garage/

Good luck with the firing!

 

[ddawg16]

I get the brick ledge thing....but why does the stem wall have to be so low?

With the brick below grade, I see a huge potential for moisture to wick up.

My footing goes down about 2'....and I have an 8" stem wall above grade....I do NOT get water into my garage.



Click on the Garage build link in my signature for more pics