concrete block basement - quickcrete slab?

[MelH]

If I build my own basement using concrete block - can I pour my own slab using quickcrete or similar?  I'm looking at the 20x30 1 1/2 story with a full block basement.

I would rather not have to get a concrete truck to the site if I can pour it myself before I start stacking block for the basement walls.

Is this feasible?

thanks
Mel

[Whitlock]

Maybe just poor a  footing do this by hand. Then you can start stacking your blocks.  Do the slab later.
Doing a lot of concrete by hand is a lot of work. Quickcrete will work fine.

But don't take my word for it my concrete skills are minimal,W

[MountainDon]

While it is entirely possible, is it really practical? This would be a lot of work, a lot of concrete. I can't imagine lifting, moving all the bags it would take. I don't have anything against the Quikrete, per se, just the use of such a large amount.

How long do you figure that would take?

Of course if you land is like mine you'd never find a transit mixer that would want to get up there.

[davidj]

600 sq ft at 4" deep slab is 200 cu ft of concrete.  And you'll probably need a 16" footing that's at least 8" deep around the edge, which is another 40 cu ft at least.  If you're using bags of pre-mix, that's 530 60lb bags minimum (or the equivalent in sand, cement and aggregate).

I've not done much concrete and I'm definitely on the lazy side, but I start trying to come up with alternative plans once it gets up to 50 bags of mix or equivalent, even if there is a small electric mixer available (with the best "alternative plan" being combining 2 or 3 projects to the point it's worth bringing in a truck).

Also, up in the woods where we are, it costs about $40 per cu yd just for aggregate or sand, once you factor in delivery.  There's probably something like $40 of cement in each cu yd of ready-mix concrete.  And the concrete truck ends up costing about $120 per cu yd once you get up to 6 or 7 yds. So you end up saving $40/yd if you mix it yourself.  Personally I'd rather lose the $40 rather than mix the equivalent of 60 bags of pre-mix!

[rwanders]

A slab pour like you plan is meant to be "monolithic"----in other words, it is supposed to result in a single massive concrete structure. Trying to do it by hand will result in multiple "cold joints" and sooner or later probably spalling at most of those junctions. I have hand mixed occasionally---it's hard to mix more than one bag at a time---multiply that by all those cubic yards and your task will soon reveal itself to be backbreaking.  I guess you can tell I think it is impractical. 

[glenn kangiser]

If you really want to do this this way I suggest getting a load of sand and a load of gravel then just getting bags of Portland Cement and do the 1-2-3 formula.  Break it into 6 pours of 10x10 each with key joints on the sides and dowels through the keys - wire or rebar underneath - 1" up in the slab.

As mentioned above, it is a lot of work.  The savings will likely be minimal if that is the only consideration.  One 10 yard truck would likely do footings and all.

[cordwood]

 You guys always post faster than me and I get the little red warning!
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So ya what they said. And if your road is very steep in places you should tell them ahead of time. I drove a mixer truck for one day and lost about 2 yards in driveway that looked more like a hill climb competition
Trying to keep the slab from leaking will be harder with a sectional pour. "Monolithic" would be code in most cases.

[n74tg]

The girlfriend and I mixed and poured the 5' x 8' concrete porch on the house I am building.  I ran the mixer and shoveled the concrete into the forms and she used a hand trowel to smooth everything I brought.  I thought about renting a bull float, but there would never be enough concrete in place to make it worthwhile until the whole slab was poured; so, we stuck with the hand trowel.  After three hours and 11 mixer loads (about 20 cubic feet of concrete) the forms were filled, but now continuing to work the stuff that had been placed first (3 hours ago) was getting harder and harder to do. 

Now, if we had had two mixers and another person to operate that mixer then I think things would have gone smoother.  What I learned from this experience was that you need to be able to get a lot of concrete mixed and placed quickly so that the whole slab is about the same consistency as it relates to working and smoothing. 

You're going to do a much larger slab than this little project we did.  Unless you have a lot of help I think you are going to be disappointed with the final result.  For a  pour of this size, seriously consider bringing it all in together in a truck.  The extra expense will be offset by the satisfaction you will get from a good looking, smooth, level slab. 

[MelH]

Thanks everyone - I appreciate the responses.