Basement Slab done wrong

Weekend Warrior DIY

I'm racking my brain thinking about what to do with my new addition basement slab. My contractor extraordinaire hand trowed the whole thing, 20' x 28', there's high points, swirl marks and low points everywhere. Not to mention that the concrete was extremely rough in texture. I mentioned something to him and he said, well I have to still put on the final coat. To which I thought, maybe I don't know enough about the process of pouring a concrete slab. He is the contractor after all. So he poured more, now the basement is roughly 5"+ shorter than was discussed and the new glue lam beam really is a head finder since it's set at 5'10" and I'm 6'3"

Can someone please tell me the process, the right process, to pour a basement slab. Type of concrete, tools, etc.

Also any ideas as to how to fix the problem, the job is nearly done and I owe him one more payment, but it really is a super crappy job and I feel it should be done right.

Any thoughts/advice would be appreciated.

Mort

Oh boy, where to start...

First of all, there are no "final coats" in a concrete slab, you pour it all at once. Normally when I go to a job where they are pouring a basement in a finished home (i.e. not one that is being built), they use a line pump to place the concrete, which use a pea gravel mix.

Its not the easiest pour, because you've got walls on all four sides, but it can be done right (and in one pour). You'd place the first 1/2 or so of concrete, level it out (rod it, as the pros say), and finish it with a bowl float (large version of the magnesium hand float he probably used). You'll then pour the rest and finish it by floating from outside the door. It kinda sucks, but that's the way to do it if the basement is walled in.

I'd hang on to that last payment until something is done about this, I've never seen a slab placed in two parts like that. If the finishing-out-the-door thing isn't feasible, I suppose he could do it in two halves so the finish would come out right, but that's beginner stuff.

Weekend Warrior DIY

I didn't think so.

I always thought you poured it and floated it as you went. Once the slab was in, that was it, it was done.

The type of concrete has got to be wrong to, there's 3/4" modified gravel in it. It's what I would consider using for footers or the like. Not a nice smooth, finished basement slab.

joecaption

There also should have been chaulk lines struck on the walls so they would have a referance point and grade stakes toward the inside of the slab area.

If there was any place where there was going to be support post set there was suppost to be deeper dug out areas for the footings.

In my area we also have to add expantion strips around the outside of the slab were it meets the walls and make the outside of the slab deeper for edge support.

Canarywood1

All residential basements are a monolithic pour of at least 3000 psi hand trowled to a smooth finish,with no apparent high or low places, concrete placement is an unforgiving project,that must be done right the first time,as there are no fixes for a botched pour except to tear out and start over.

Weekend Warrior DIY

That kind of pour has to be done by a special machine, right? Not your average ordinary concrete truck?

I agree, there's nothing that can be fixed unless it's ripped up and redone. Which in the end is what would make me happy. However I don't know how to go about that. I drew the plans, allowed by township, I am not an engineer, more of a mechanical designer, and I didn't call for a certain concrete. I honestly don't feel as though I should have to, it should be code to do it a certain way with a certain concrete (if applicable) and with a certain finish.

I'm going to mention something to him today, if I even see him as it's raining and those guys seem to disappear in bad weather. What do I say? How do I go about proving that it was done incorrectly? I mean these high/low spots are not only visible with the naked eye, they're high enough to trip over.

jomama45

Just so I understand, the contractor poured the entire floor at one time, and then later added another 5" floor over the top of the first floor? I can't even begin to imagine why this would be done............

Weekend Warrior DIY

He poured a "rough" pad for lack of better words, then when I said something about how awful the floor was and why isn't it smooth, he said he wasn't done, there was a finish coat. I have never seen a basement slab poured twice.

The first pour was on top of a plastic membrane and wire mesh, which is on top of stone. Which is supposed to be 4" per local code. Then he poured another coating on top of that, to smooth out the bumps......

Canarywood1

There's no special machine for that type of pour,just ordinary 3000 psi concrete,but you do need an experienced crew to do the job,which he surely doesn't have,do you have a permit for this job?,might be time to get an inspector involved,be a good idea to get some pictures of what you have if push comes to shove.

Mort

No special machine, if the mixer can access the placement point (the door). If it can't, you'll need a line pump, which is why I suggested the 3/8" mix (3/4 is fine for a basement slab, but line pumps have trouble pumping it).

Sounds like it started out good (with the plastic and the wire mesh), but went wrong from there. Unfortunately, it all needs to be ripped up and replaced. If you use a line pump, make sure your concrete supplier knows, so they can send you a mix that is line pump friendly.

As far as dealing with your "contractor," good luck, may the Force be with you.

Weekend Warrior DIY

Yes! I'm happy to say I do. He has been out to inspect framing and a few other things but I don't think he inspected the slab.

Agreed. I'm only disappointed I didn't get anything of it before the finish coat.

Canarywood1

Might be a good idea to ask him some questions regarding the slab,and have him look at the so called finish product,and a floor can be cored to get a look at it internally so to speak,you'll see the two pours and if the wire was pulled up into the concrete or left laying on top of the stone base.

paintdrying

Might not be a bad idea to have another concrete contractor come and look at it. Document exactly what he tells you is wrong. I have watched maybe 100 concrete basement slabs get poured in my life time. Not start to finish but I have witnessed many pours. In the final stage of many basement floors and guy will go onto the slab with special support floats and put the final float on the slab. It is very interesting to watch it done. Not all basements are done like this, garages are done this way always because oil can leak on a garage floor and they need a smooth finish. Of course this was all 20 years ago so things may have changed since then. I tiled over a basement slab like yours and it came out pretty good. If this guy did not deliver I would suggest seeking legal console.

Venter

Reading your last sentence, it seems like you have high and low spots right now, even after he poured the additional 5". Is that true??

Weekend Warrior DIY

Yes, it is true.