Large Concrete Slab

[redfox]

I am building a 48x48 pole building to be used as a garage/machine shed. I definitely want a concrete floor. Several questions:

(1) Since the weight of the pole building will rest on the poles (not the slab), do I need a thickened footer around the perimeter?

(2) Is 6" thick appropriate for this slab?

(3) I have been told that if I order fiber-reinforced concrete, I do not need rebar/wire mesh -- is this right?

(4) I know I can't handle a single 48x48 pour all at once -- what is the best way to section it off? If I formed, say, four 12x48 sections, how long should I let each section cure before removing the form and pouring the next section?

(5) Am I absolutely crazy for considering trying to do this myself (with the help of a few good friends)?

Thanks!

[Rich]

1. A thickened footer is not necessary unless you plan on building walls between the poles - then it becomes a convenience for framing as I assume you will have a beam of some sorts between poles.
2. 6" is appropriate.
3. I would place rebar to be on the safe side being that it's for equipment.
4. Four 12' sections would be fine.. make sure to provide control joints along the 48' length. Probably every 8' across. You can strip and pour the next day if you wanted to.
5. Not crazy .. maybe just a glutton for a little punishment. I would suggest putting a broom finish on it to hide any defects in the finish. Not that you won't be able to finish it well - just that there's a chance :) Get a bullfloat with at least a 12' handle, a magnesium float. If you do a broom finish the mag is probably all you'll need.. if not then you'll need to steel trowel it also.

[redfox]

Thanks! So, if I pour one section and let it cure overnight, should I pour the next section directly against it? Or should I place some sort of material between the two sections, and/or perhaps somehow key them to prevent vertical movement?

[RobBase]

Fox, all of Rich's suggestions are good ones. In addition, if you have ever finished concrete before and are willing to learn at the risk of a little $$, rent a trowel machine with combination blades. It's sort of like a floor polisher for concrete. An experienced finisher could finish the entire slab by himself, save for the edges with one and have it smooth as glass, literally!

For your pour joints, go to a concrete/masonry supply house and ask for some "form-a-key." This is a sheet metal form pressed into the profile of a keyway. It comes with metal pins that you drive into the ground and then clip the form a key onto them. It will act as your form and also a keyway to lock the slabs together.

[redfox]

Thanks for the suggestions - sounds like a great way to go! Hmmm... How much concrete does a standard delivery truck carry at once? A 12x48 section would require about 11 yards. Is that a reasonable amount for two people to handle at once (with a bit of margin for inexperience :wink: )?

[Rich]

A typical truck can carry 10 yards.. very seldom do they load them to max though. I would suggest having 2 trucks with 5.5 yards each. It will give you a little more time to place the concrete also. Have one truck come about 30 minutes after the first. I would suggest having 3 people. 2 to place and screed and 1 to float and begin finishing/edging.
As a suggestion I would rent a good laser level and do wet screeds. Not near as much work as pipe screeds.