Estimate for Slab

[DickWilson]

Need an estimate for a 40x40 foot slab, formed and poured on owner prepared site. Mahalo, Dick

dick wilson
"Nothing is idiot proof,because idiots are so ingenious!"

[john the architect]

Dick, be sure to specify what you want. I have had good success with fiber additives reducing the need for rebar in the slab. There are also waterproofing admixtures if you need that. Be sure you spec any jointing and edging details and the final finish (broom, exposed aggregate) and if it needs to be kept curing -agent free for acid staining or other aesthetic finishing.

John Maloney
310.562.0362
johnmaloney3@mac.com
Hawaii Architect AR8082
www.jmagreenbuilding.com
www.greenrentalhawaii.com

[Ryan.]

I asked a local builder for a rough idea of what my slab will cost me. He told me to plan on $8 per square foot, including labor and materials. I'll be interested to hear what others here have to share.

[Aliismc]

Ryan your figure is pretty close. It will depend on the labor quote you get for the foundation, the amount of basecoure you need to prepare for the concrete, who you get the concret from, and the deliver charges of the base course and who you get it from. For myself the eight dollars per square foot is a little high but a good figure to for an estimate. Mine was over 3000 sq feet both house and shop and came in at around 7.50 per sq foot give or take a few cents

ALOHA http://myhawaiipardise.blogspot.com/

[Kapohocat]

yes, if rebar & remesh, and concrete hadn't gone so high it used to closer to a 1:1 ratio labor to materials now its seems to fluctuate to about 1:1.5 to 1:2.

[DickWilson]

Mahalo for all the quick replies. I'm asking for a friend who wants to put up a metal farm building and wants to get it permitted and done right. He plans to prepare site, no plumbing that I'm aware of. Looks like I also forgot to include my E-Mail,Duh, Dickwilson836@msn.com

dick wilson
"Nothing is idiot proof,because idiots are so ingenious!"

[Wao nahele kane]

$8 a sf for a utility pad? – Yikes! - I'll stick with my MQ 9cf mixer, raw aggregates, Hawaii 94lb bagged cement and fiber mesh for $1 and change a sf. They better be stamping,staining and putting a friggen gold band around it for $8 a sf. JC!

From quotes I've received in the recent past here... that price is too high per sf.

E ho'a'o no i pau kuhihewa.

[Kapohocat]

quote:

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Originally posted by Wao nahele kane...I'll stick with my MQ 9cf mixer, raw aggregates, Hawaii 94lb bagged cement and fiber mesh for $1...

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Preface: I am not trying to say you are incorrect, but here is the reality in my country. (and for those who know Robert he is standing here behind me critiquing and giving me the calcs!)


Yes you can do it cheaper than $8 for a small slab but not more than maybe 10-12%. Start deducting from the $8 for the items you have on hand below:

.....if you have a mixer that you own, and a truck you own to haul to aggregate (free labor to shovel aggregate out of truck), compactor for compacting gravel, form lumber, and own a bird to power trowel slab, rebar bender, stakes, and own the floats already .... and if friends who come over for free to help you shovel, mix and pour, just have to buy the fuel, cement, and rebar/remesh/fiber, lunch and drinks, it is cheaper for you for that project.

The big cost is not labor - it is the materials. In 10 yrs, 3500 PSI (7.5 bag mix) has gone up almost $65/yard - 65%.

And for the labor - As my brother the airline pilot tells me, you arent paying the big bucks when things are going good, you are paying me for the skills and experience to keep you walking away from a landing. It's not like framing - if something isn't right, you cant easily go back in and cut it out, and do over.


Most people don't own all the tools and even rentals are expensive. Usually friends aren't real interested in back breaking labor for a day (unless your friends are masons or firemen). And to buy all these items for a one time use is astronomical. The big float alone is very expensive - couple hundred bucks with the extra poles. If you are going to do a lot (thousand yard) of concrete - maybe it makes sense to purchase everything.

It is also very harrowing to have a bunch of unskilled friends do it for free when you have one or two skilled masons/firemen and 8 newbies. We know for a fact as we tried this out on a 16 x 36 slab for our house when we lived in the Acres.

The slab Dick was asking about is 40' x 40'. The concrete alone at about 27-28 yards with the footings is $4800 w/ tax or about $3/SF. This slab most probably can not be poured with a mixer as the county wont allow cold joints in the footings. IMHO, if you did try to do the footings with a mixer so you dont have a cold joint, you would need a bare minimum of 6 people one day, as they will get tired and will slow down. And thats just the footings. At 8 yards thats 58 bags of cement - 7.5 bag mix - x $15.02 (we just bought cement yesterday at ICO) plus sand and basecourse. Fuel - Five trips to pick just bags of cement in a standard pick up truck where you can haul 7 or ten trips.

Here is a simple equation (and I know economy of scale will bring pricing down a little.)

Small slab 5 x 4 = 20 SF = $8*20 = $160 - even if you do it in a wheelbarrow, but you have fuel (to pick up materials), sand, cement (approx 2-3 bags if 4" thick) and a little remesh plus tools. Materials & fuel will cost more than the $8 so I dont know how you figure a $1/SF at any size slab. But if you can work that out, I got a walkway, and a 30 x 12 ft driveway to pour. Come on over - I'll make lunch and give you a cold beer!! [][]

When we pour ours, it is going to cost me 25 cents a SF at least for beer and lunch for the free labor.

And in only the most respectful way I would like to say that your $1 a SF is not just unrealistic but untrue. Unless it is a tiny little slab, pouring from a mixer doesnt really come out price-wise ahead.

What we all forget - and I do too when we do bids - is fuel is so costly and to say or we'll just run to town to pick the cement up - (yesterday 4 bags of cement and some lumber) cost us about $35 for the truck. And then we had to go get sand.

We would have ordered the concrete but we are doing the piers one by one on the weekends. So they'll do 2-3 today and more next week.

-Cat (& Robert because those who know him, know it is painful to watch him type).

Edited just for typos!

[Wao nahele kane]

"And in only the most respectful way I would like to say that your $1 a SF is not just unrealistic but untrue. Unless it is a tiny little slab, pouring from a mixer doesnt really come out price-wise ahead."

A "$1 and change" is what I said... I didn't say "$1". Even if I use #3 sand as my only aggregate (most expensive stuff) - I end up with less than $2 sf @ 4" thick. #3 sand runs $1200 per 20 ton load delivered = (15 +/- yards). Larger aggregates are by far much-much cheaper.
I stand by a "$1 and change" regardless of claims to the contrary, that’s what it cost me. BTW... yes I do own my own concrete equipment and we have our aggregates delivered in bulk and transport them around via backhoe. No... I won't do your pads; I've retired from construction/contracting/developing and designing.
If you want to do concrete for less… pick up the equipment and set up a small base yard in some unseen corner of your lot. It can be done for less than $3 A CF if you set up for it. You can even set up your own dry storage for bulk delivered cement and save even more. Why that has to be argued is beyond comprehension.
$8 a sf for a pad is very high, I was quoted under $7 a sf for a pad not even 6 months ago by 2 different contractors. As per the rest of the hoopla, 30 years in the business, I know all about labor and other expenditures.

Edit to add -
BTW... back '07.
For a neighbor, myself and 4 other neighbors set up and poured a 20’X30’ pad with turned down footings on a weekend. It isn’t as farfetched as one might hope to think. We also poured a 10X12 another weekend within an afternoon via a 9cf mixer.

E ho'a'o no i pau kuhihewa.

[DanielP]

Wao Kane,

Da mus bee sum gooood sh*t you smokin'!