concrete floor questions

[roadless]

How thick is usual for a shop floor? About how much would a 40 x 60 poured concrete floor be?( I live in Mass but the barn is in the southern adirondack area) I would like to surprise my husband.( Although last time I "surprised " him he told me my heart was in the right place but my head was up my butt! yikes ......but this time it will be different!!

[bill not in oh]

Originally Posted by roadless

last time I "surprised " him he told me my heart was in the right place but my head was up my butt! yikes ......but this time it will be different!!

what makes you think this time will be different?LOL...

What is it's intended use? If he's gonna park or drive a combine on it, the answer is different than if he's gonna have a lawnmower or two in there ( or a few goats, or compact tractor, or .....) The specific mix of concrete will vary depending on use as will the thickness and construction/finishing technique. All variables that will significantly change the final cost.

[ericjeeper]

six for anything heavier. 4 inches thick will require 30 cubic yards of concrete. Not sure how much a yard by you. 6 inches will require 45 yards of concrete.

[roadless]

[QUOTE=bill in oh]

what makes you think this time will be different?LOL...

....well the odds are with me...at some point I gotta get it right I called a guy in the area and the estimate is 2800 just for the concrete(4in), then I would have to hire others to work it. Ouch! My dh will use the building for storage (rented to neighbors small farm equipment, etc) and may use a portion for a welding/blacksmith shop)so...maybe 6in would be best.

[Jul]

Don't forget rebar if there is going to be heavy equipment on it.

[wdchuck]

Call a few more places, they should be pretty close in costs though.

Check out the finished work of potential finishers, if possible.

Considering the size and potential use of this building, thicker would be more prudent, and you may want to inquire as to a vapor barrier under the floor, it will cut down on the seasonal condensation if not eliminate it, considering the climate you live in, it'll be good for any metal(equipment, tools, machinery, etc...), by reducing moisture inside.

Can you put in a floor drain?, nothing fancy, just a hole with stone as backfill and a grate on top, then the contractor finishes around it and allows a slight pitch to it.

With many of the modern mixes, it's reinforced with fiberglass, thereby eliminating rebar, ask your concrete supplier about first, then question the finishing contractor about it, see if you get consistent answers.

good luck on this, it's not a project to be taken lightly, awful hard to correct something afterwards.

[sugarbush]

I am figuring that you need 31 yards to do 4 in and 44 to go 6 in........they are charging you 90.00 per yard at the price you stated which seems about right for that area. You will pay as high as 1.25 per square foot for a finisher so figure another 3000.00 on top of the concrete. The concrete needs to be poured on crushed stone base and that will run another 19.00 per ton delivered and you will want probably 80 or 90 tons. If you will be parking farm equipment on the slab get 4000 mix, no air fiber reinforced and 25% fly ash if available in that area. The stone needs to be compacted well as the concrete will push it down another inch or so if it isn't and you will need more concrete if the grade is off.....stone is cheaper than concrete and if you run short on the slab the concrete company will charge you a short haul fee for the make up truck. The finisher should lay the stone down, compact it and set the forms as part of his price....... If you are there when they do it DO NOT LET THEM ADD WATER TO THE TRUCK prior to pouring out...... they use hand signals with the driver to tell him how much water to add, so you will not even know it is happening...... the truck will rev up the engine real high while mixing the water into the load. If the load arives dry you can have them put 1 gallon per yard on each truck, but no more. It is better if you can have the company send superflow water reducer with each truck to be mixed into the load when the truck arives.... you can ask the finisher what slump they like to pour on and based on that the concrete company can figure out how much water reducer is needed for each load...... in the end the concrete company and finisher will hate you, but its your money so make sure the job is done right.

[stanb999]

Originally Posted by sugarbush

I am figuring that you need 31 yards to do 4 in and 44 to go 6 in........they are charging you 90.00 per yard at the price you stated which seems about right for that area. You will pay as high as 1.25 per square foot for a finisher so figure another 3000.00 on top of the concrete. The concrete needs to be poured on crushed stone base and that will run another 19.00 per ton delivered and you will want probably 80 or 90 tons. If you will be parking farm equipment on the slab get 4000 mix, no air fiber reinforced and 25% fly ash if available in that area. The stone needs to be compacted well as the concrete will push it down another inch or so if it isn't and you will need more concrete if the grade is off.....stone is cheaper than concrete and if you run short on the slab the concrete company will charge you a short haul fee for the make up truck. The finisher should lay the stone down, compact it and set the forms as part of his price....... If you are there when they do it DO NOT LET THEM ADD WATER TO THE TRUCK prior to pouring out...... they use hand signals with the driver to tell him how much water to add, so you will not even know it is happening...... the truck will rev up the engine real high while mixing the water into the load. If the load arives dry you can have them put 1 gallon per yard on each truck, but no more. It is better if you can have the company send superflow water reducer with each truck to be mixed into the load when the truck arives.... you can ask the finisher what slump they like to pour on and based on that the concrete company can figure out how much water reducer is needed for each load...... in the end the concrete company and finisher will hate you, but its your money so make sure the job is done right.

Well it seems like someone knows something about concrete.......

The only things I would add is to avoid pouring in bad weather. (too hot/too cold.)
Don't let them add water to the surface for finishing. This will cause dusting and efforvesense. Put in wire mesh. The fiber really does not reinforce it minimizes cracks only.

Now the most important thing for the floor is wet curing if possible. What you do is pour the floor and finish. Wait several hours. When the floor is solid enough that even walking doesn't cause blemishes. wet the floor with a hose and cover it with tarps. the next day you saw cut expansion joints (as close to 10X10 as you can convince the contractor.) Now you wet it again and keep it covered as long as you can stand it(3 days min. 28 days would be the practical max. but a week to 10 days should be good enough.)

As far as the price of the concrete 90 a yard is a good price. But when dealing with a contractor you must remember that they get a discount from the ready-mix company. Often 10 dollars a yard or more. So you shouldn't pay more than .....twice his price for the whole job and that includes the wire mesh. So your total would be 180 a yard. So at 4" it would be around 5400 but thats just the concrete. You will still need the base prepared and stone as the base.

[canfossi]

Don't underestimate yourself Roadless, I'm sure you'll do fine and he'll be happy with the surprise. My garage floor was 4" thick, but that's just for a garage. Chris

[sugarbush]

Originally Posted by stanb999

As far as the price of the concrete 90 a yard is a good price. But when dealing with a contractor you must remember that they get a discount from the ready-mix company. Often 10 dollars a yard or more. So you shouldn't pay more than .....twice his price for the whole job and that includes the wire mesh. So your total would be 180 a yard. So at 4" it would be around 5400 but thats just the concrete. You will still need the base prepared and stone as the base.

I personally would pay the finisher and the concrete company seperately. You can take advantage of the finishers discount, but if he dosn't pay his bill the lean will go against your property and you will have to track down the finisher.

The wet cure is a good idea, but not always practical. The chemical cure and seals are second best .

[Farmerwilly2]

While it would be best to have it all done at one time you could do it in smaller pours as funds allowed. A 20x30 pour (1/4) of the floor would take 8 yds. If you can find a local finisher that makes an easy Sat. morning pour, real nice for a fella looking for a little side work. Might get you a better price.