Concrete Flatwork Ballpark

Let me preface this by saying that through high school and college I worked with my father remodeling houses. One of the most frustrating things for me was when we would go out to a potential project, think through all the logistics of it, figure out a detailed price and then to have the homeowner's jaw drop and you realize you just wasted an hour and a half of your life.

That said, I would like to get at least some idea of a ballpark on what to expect before I call concrete guys for an estimate. My wife and I recently upgraded our hot tub and this one is much bigger. We are contemplating whether to do our own (by hand) excavation and concrete work (crete from bag mixes) or have it done for us.

Anybody have any clue as to what we should expect to excavate and pour an 9'x11' 4 inch thick reinforced flat slab?

9'x 11'x4" Slab. 9x11x.334=32.67 sq.feet
32.67 divided by 27= 1.21 square yards of concrete. Concrete around here is about $100 per yard. Bulk delivery usually has a three yard minim charge. So the concrete would be around $300.00
Rebar and finishing labor would be about the cost of the concrete. $250
Removing the old slab and digging new site should be no more than $300-$400
So you would be in the $900-$1000 range. I would recommend removing the old slab yourself and doing the grade work. If you have some where to go with the old concrete. Then your pour job could be an afternoon fill in job for a concrete guy. This way you can get a good job without a big bill. I don't know where you are at but some of the concrete guys around me here have their own small mixer truck that is on a pickup chassis. That would make your job very easy and help hold the cost down.

Hi Ryan,

If you should decide to get rid of the old concrete yourself, as JD Seller recommends, and as I would, take a look on Craigslist under the "Wanted" category to see if anyone in your area wants the broken concrete as fill. I paid several hundred dollars to get rid of many truckloads of sod and dirt before it occurred to me to see if anybody wanted it. Someone did, and it was only a few miles beyond the place I was paying to dump it. Oh well.

Stan

JD's estimate is right in line with what I've seen. The biggest variable will be the cost for tear-out and excavation.

A 9x11 pad is well within the abilities of a homeowner to do, although you'll need the help of someone who has previously finished concrete. I would suggest making the pad a bit thicker than 4 inch, as the incremental cost of concrete isn't significant.

If you decide to go the DIY route, some redi-mix outfits provide concrete trailers specifically for small loads. You can rent a mixer, but it gets to be real work to mix more than a yard of concrete. (When I lived in Cairo, I was surprised to see that there were very few redi-mix plants. Instead, concrete was mixed on site, even for large apartment building projects. I guess that's what you do when labor is almost free.)

If you're tearing out old concrete, try to find a nearby concrete recycler. They may charge you to dump, but the cost is minimal compared to dumping at a landfill. I just did a tearout of my sidewalk and garage apron. The sidewalk busted up easily; I just pried it up, slid a 2x4 under it and it with a hammer. But I had to rent a jackhammer to bust up the apron, it was much tougher concrete.

Probably not out of reach for you to tackle, for the demo, you may want to rent an electric jackhammer, like a Bosch brute or similar, depending on how strong the existing is, you may also want a variety of bits, say a wider flat bit for when you need to chip the edges square if necessary, I like a narrow flat bit for most of this work, though you may need a pointed bit to get the initial hole started. I find its easier to establish a face and work a line breaking off pieces into where you have already done so, you want to fracture it more than puncture it if at all possible.

With the pour, one thing I can add is that mixing by hand is slow, and you may have one part of it start to hydrate (cure) while you are still placing fresh material which means that material needs to be screeded off, and finished, so if you pour yourself, depending on weather conditions, temperature etc. you need to hustle to get that form filled as quickly as possible. I would prefer to fill the form at once, and just worry about screeding, floating and or finishing the entire slab. Around here there are small quantity batch trucks, costs a little more but not like a short load from a regular batch plant truck. Also saves you a lot of labor and getting a small mixer, your materials set up to mix rapidly.

Funny, well not really, but doing estimates will always have that element, not every one will hit, have been there many times, sometimes people don't realize the cost of things, and or hiring out to get it done, even after providing an estimate with minimal profit.

Lots of variables you didn't mention, like assesibility to the work site, soil conditions, mitigation to the yard and landscaping after the job is done, stuff like that. I would guess bids will run in the $3000-$4000 range. Most decent contractors don't like to mess with a small project like this. They still have all the overhead expenses to pay for no matter what size job. That being said, there probably are guys out there that would do it for $1000. But do you want it done right or half-azzed?

Team Zinger, where are you located???? You only would pay $3000-4000 for slab that size in some major city. I have done and had done many concrete jobs here in north east Iowa and it would not have cost that much. The only way for that high of a cost here is if you had a lot of other problem things to work around: no way to get into the yard, electric or other utility wires, water or waste water pipes.
Just wondered on your location.

I did not see your comment about the contractors not wanting that small of a job, until I reread the post. Maybe a big road type contractor would not be interested. With the economy like it is right now the concrete sud contractors around here would jump at ANY work right now. I just had a new barn floor poured and the finish guy charged me about half of what he Bid two years ago. I asked him why such a difference. He told me that my job allowed him to make pay roll and make HIS house payment. He had no other work for the next three weeks lined up. The building trades around here are hurting.

Billy you must have had better luck with the electric demo hammers than I! I rented one years ago to take out these stairs to lengthen that concrete wall for a garage addition. I was extremely disappointed in the results. I through it to the side and grabbed a sledge hammer. I'll never rent one again, I'll rent a 185-CFM compressor and a 90-pounder.

You obviously need to buy a compact diesel of your favorite color with back-hoe so that you can save thousands on the excavation. At least that's what your wife needs to think, Then all you need is a concrete floor guy with some planks. I would suggest put in a patio at the same time because a full load of 'crete costs about $.99 more than a half load.

That's quite a bunch of bags to handle - would it be more cost effective to have concrete delivered ready mix?

I had a fiber reinforced floor put in last year, 2400 sq ft. Cost was $5500. That included everything. It was less than what it had been bid on 10 years ago. Lots of guys working for less now.

I like this picture. Some one has a very good wife/girl friend/sister. LOL I would recommend that they get this Lady a good pair of work boots. I don't think flip flops are approved for jack hammer work.

(quoted from post at 18:27:59 07/11/10) I like this picture. Some one has a very good wife/girl friend/sister. LOL I would recommend that they get this Lady a good pair of work boots. I don't think flip flops are approved for jack hammer work.

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Not approved on a job site, but that's my front yard when I lived in town, and at least 20-years ago!
Yeah she's a pretty good girl, runs tractor, pours concrete, does framing work, paints houses, pretty much anything I tell her girls can't do! :lol:

She wants a pond in the front yard, she digs a pond in the front yard! :lol:

Oh you are right, there is no substitute for the big ole tow behind compressor and a 90 lb'er, figured I would not get too crazy with overkill, just that those are not as easy to rent, etc. I've got an old Bosch, its seen its day too, like since 1982, they work, but you really have to fracture, use a drill sometimes to help that, before the pieces break off, like you said, if you need to, get a 90 lb'er and or a contractor who will use same, to get it done.

Contractors around here bid flatwork by the square foot. Getting up to around $5 a square ft. or better and may not include steel. Last bid I got years ago was 2.25 a square foot and steel was cheap and concrete was $50 a yard. You have about 120 sq. foot. Those with a bobcat will bid tear out too. Tear out and form up one day, pour the next, pull forms the next. I don't see anything in your post about tear out of old concrete, but any flat work will break up with an electric jack hammer but you will need bolt cutters to cut the 6x6 steel remesh and a torch or recip saw with metal blade for the rebar. The jack hammer will work you to death. Not the jacking part but lifting it up and out and repositioning it all the time. If you can't get a heavy truck in there they extra to use wheel barrows. Some use a bobcat bucket but be ready for yard damage from a bobcat.

Don't try to pour that big of slab with quikcrete. Buy a bag and see how long it takes and how hard it is to mix in the wheelbarrow with a hoe. Multiply by a hundred and some bags. With a mixer, everything still has to be carted around to the work area.

Still need a part truck load of sand/gravel for a base. Then rent a compactor. Then rent a concrete saw to cut it. 9x12 is at the limits of going without a cut/joint. Have fun. Rent a bull float, trowel, and concrete broom as well. I wouldn't try it without 3 to 4 people with the muscles to work concrete. Let us know how it goes.