Concrete advice needed.

Im going to be leveling a concrete floor that is off anywhere from 2 to 8 depending on which are you measure from. I estimate that I will be needing about 85 bags of 90 lbs. concrete. It is too much for me to do it all in one go so Im thinking of blocking off the floor into three sections and doing it on three different days. I will have to wait for one area to set before going on to the next. Since the floor which Im going to level is already concrete Im not going to use any steel mesh but should I use any kind of concrete adhesive on it before I start pouring? Im not worried about the seams that Im going to have because the floor will be covered with Thin-Set and ceramic floor tile. My main question is: Is my reasoning sound and am I missing anything. I would appreciate any advice or suggestions anyone has to offer, thank you.
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On Tue, 19 Jun 2012 09:23:44 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

to 8” depending on which are you measure from. I estimate that I will be needing about 85 bags of 90 lbs. concrete. It is too much for me to do it all in one go so I’m thinking of blocking off the floor into three sections and doing it on three differentdays. I will have to wait for one area to set before going on to the next. Since the floor which I’m going to level is already concrete I’m not going to use any steel mesh but should I use any kind of concrete adhesive on it before I start pouring? I’m not worried about the seams that I’m going to have because the floor will be covered with Thin-Set and ceramic floor tile. My main question is: Is my reasoning sound and am I missing anything. I would appreciate any advice or suggestions anyone has to offer, thank you.
I think you have gone over the point that it is best to get a ready mix truck and a pump if you need one. The problem will be getting it level no matter how you pour it. If this is inside, heat may be a problem too. That much concrete will really heat up a room and it will set up very fast. Chalk a line all the way around the room at he finished height and another one 3.5" above that to use as a guide for a 2x4 screed. Blue chalk comes off, red doesn't Have them mix this at a 5 or 6 slump. You are giving up a little strength but it will work easier. I would paint link on the old floor to get a better bond.
If you do decide to do this in steps, get the next section going as fast as you can, while the preceding one is still green and paint link on that joint too. It may mitigate the cold joint problem somewhat. This will usually crack anyway. Use "flex" thinset to mitigate that or put a membrane down first. The membrane method is what most builders do here.
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On Tue, 19 Jun 2012 09:23:44 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

to 8” depending on which are you measure from. I estimate that I will be needing about 85 bags of 90 lbs. concrete. It is too much for me to do it all in one go so I’m thinking of blocking off the floor into three sections and doing it on three differentdays. I will have to wait for one area to set before going on to the next. Since the floor which I’m going to level is already concrete I’m not going to use any steel mesh but should I use any kind of concrete adhesive on it before I start pouring? I’m not worried about the seams that I’m going to have because the floor will be covered with Thin-Set and ceramic floor tile. My main question is: Is my reasoning sound and am I missing anything. I would appreciate any advice or suggestions anyone has to offer, thank you. Use white glue bonding agent (PVA) to bond the new concrete. works spread on the old before pouring new, or mixed into the concrete... Google PVA Bond
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On Jun 19, 12:23pm, snipped-for-privacy@gmail.com wrote:

it will be far cheaper to get a ready mix truck to deliver the already mixed concrete. they have a self leveling type to get it dead flat. 85 bags cost a fortune
are there any cracks in the existing concrete? if so the overlay will crack and so will your new tile:( theres a mesh you imbead in the thinset but i dont know how effective it is
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wrote:

8 depending on which are you measure from. I estimate that I will be needing about 85 bags of 90 lbs. concrete. It is too much for me to do it all in one go so Im thinking of blocking off the floor into three sections and doing it on three different days. I will have to wait for one area to set before going on to the next. Since the floor which Im going to level is already concrete Im not going to use any steel mesh but should I use any kind of concrete adhesive on it before I start pouring? Im not worried about the seams that Im going to have because the floor will be covered with Thin-Set and ceramic floor tile. My main question is: Is my reasoning sound and am I missing anything. I would appreciate any advice or suggestions anyone has to offer, thank you.

I don't know about 'far cheaper' if all you count is the $'s----- But it will damn sure be cheaper in the long run, and a *whole* lot easier.

Not to mention-- How did that floor get *that* far off? Is it unsupported someplace and just waiting for another few tons to send the whole works tumbling into a hole?

I think I'd go with the fiber embedded concrete. . . . Strike that. I'd call a couple redi-mix places, tell them what I was up to, and ask for their recommendation.
Jim
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+1 to that. I've seen the Holmes crews on TV use some new cement product for floors like garages and basements. It comes in a cement truck but is much more liquid like, so it pretty much self levels. Then they spray it with some liquid that aids the curing of the surface. I'd check into it as it sound like it could be perfect for this application.

I was wondering that too. If there is some underlying problem, the new floor could just continue to sink. 8" is one hell of a lot.

+1
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That is about 2 yards of concrete. Many places charge you for about 3 or 4 yards, or add a delivery charge even if you want less. However, when you get to about 2 yards of the bag do it your self stuff, the price will probably be the same or cheeper for the delivery even with the extra charge.
I mixed about a yard of concrete to put in a hole just to support a radio tower. Where I wanted it, a truck could not go and I was not about to move that much by hand in the time the truck would be there. It took several hours to do the mixing for 43 bags of the 90 pound and that was with a rented mixer that I could only put a bag in at a time. The mixer would hold more, but I could not handle more.
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-snip-
-snip-
The OP is using 90 bags-- 90x44= $360
WAG [if his math is right-- and mine] if he is talking about 80lb bags he's doing about 1.777 yards.
In my neck of the woods, there is a company that delivers 1 yard if they can just dump it and run. They don't offer much in the way of special mixes-- but they'll get you good enough for a pad or sidewalk section.
Downside is- if you need 1.7 yards, they need to make 2 trips-- and it is about $200 a load.
Another company charges for 4 yards-- if you use less than 4 yards, they will deliver it, but you're paying for 4. They also have about anything you could ever ask for in a mix available, come with some pretty serious chutes, and an accommodating driver. -- Just don't keep him past whatever the 'dump time' is supposed to be-- Then it gets expensive.
That's who I used last time-- That was 2004 & it was $400 for 5 yards. [turned out to be the same price as for 4 yards-- so I poured a pad and a couple of steps]
I think it might cost a few bucks more for the OP- unless he is in a unique area-- but it will save him a boatload of aggravation and he'll end up with a better job.
Jim
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snipped-for-privacy@gmail.com wrote:

That's 7650 lbs of concrete (dry ingredients). When you add the water (estimating 680 lbs of water) that takes you to 8330 lbs. That's about 57 cubic feet of concrete (about 2.13 cubic yards).
Your average depth is about 5 inches. The amount of concrete you're planning on would cover 138 sq. feet, 5 inches deep. That's almost a 12' x 12' area.
That's a lot of "filler" to level a floor. I don't see why you'd need so much.

With a conventional 3-cf mixer you could do about 1800 lbs in about 3 hours (in 10 batches, each being 180 lbs or 2 bags).

That's your call, but I still think you're pouring too much to level a floor.

No.
The slab that you're pouring on top of another slab isin't going anywhere.

Thin-set on top of 5 inches of new concrete on top of an existing concrete floor?

You can set ceramic tile directly onto cured concrete using mortar.
How big is this floor (area) anyways?
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On Tue, 19 Jun 2012 09:23:44 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

IMO, anyone wanting to mix 85 bags of concrete is not of sound mind and is not reasoning at all. Get reddi-mix delivered and have help standing by.
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wrote:

Hey-- I resemble that remark!
At least it was just under a yard-- about half of what the op proposes--- and it was a driveway, so the surface wasn't as critical as inside.
Jim
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wrote:

new stable cleaner in the dairy barn, new stabling where the horse stalls got taken out (I swung the sledge for that project too), new floors in the hog stable and half the manure yard. I was mixing and hauling pretty well from sun-up to sundown for close to 2 weeks except for chore time between 1st cut hay and wheat harvest (end of june). When I ran out of gravel I had to go out to the pit with the loader and bring in a few more buckets full (thankfully only a hundred yards or less from the barn). Can't remember how many bags we went through, but it was a 2 bag mixer if I remember correctly. The boss was a slave driver - and he levelled the concrete as fast as I could haul it.
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On Jun 19, 9:23am, snipped-for-privacy@gmail.com wrote:

I hope you're leveling a floor that is a slab on grade. You'll be adding 30 to 100 lbs/ sq ft, not a big deal to a slab on grade but a load to be concerned about if the slab is elevated.
If there are cracks in the existing floor they will likely telegraph through your new unreinforced overlay.
You're adding ~ 2 yds (~8000 lbs) of new concrete..... way too much to mix by hand. :(
How did the floor get so far out of level? cheers Bob
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wrote:

The OP didn't say but I bet this used to be an attached garage and he wants the new room to be flush with the house FF
I ended up doing the same thing myself and that is why I know about the heat problem. It made that room about 110 degrees when the concrete started curing.
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snipped-for-privacy@gmail.com wrote:

Without more information, it may be difficult for people to provide the best feedback.
My thoughts would be (like others) to consider why the original floor is so out of level. Also, adding up to 8 inches of concrete on top as a way to level it seems to be way too much concrete, more expensive than necessary, and may add too much weight to the existing concrete floor.
How thick is the original floor? Could you break it up with a rented jackhammer and then create a new level base for the new concrete floor?
Or, if you are still committed to idea of just leaving the original floor in place and adding a new floor on top, maybe it would be possible to use a modified or crushed stone base as a filler for the deeper areas and then pour a less thick concrete floor on top of that. I don't know what type of filler or base material would be best if you do this idea, but maybe others here would know.
But, since the OP appears to have posted his question and then did not return to read the responses, it may not matter what suggestions people here offer.
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