Barn & Storage Buildings- Concrete Floors

Scotty:

A lot of how things are done is regional in nature depending on soil types, frost line, etc. However; my choice would be 6" thick with 1/2" rebar on chairs every 24" on center each direction. Sawcut joints are the only way to go, especially if it's a shop type situation where you'll be using creepers and rolling shop stools, and tool cabinets. I cuss our tooled joints every time my shop stool's casters hit one. At the very least make sure there is a vapor barrier under the slab to keep soil moisture from wicking into the concrete. If you can afford insulation, go for it. How you prep the subgrade is going to make all the difference in longevity of the slab.

Have you ever seen how wire mesh is installed? First it's dropped on the ground, then the concrete is poured, and then Jose and crew in theory pull the mesh up to the center of the slab while they are standing on the mesh.

If you want to fill the control joints, you can; but I wouldn't use silicone (assuming you mean the stuff for aquariums and the like). Check what the local concrete supply house carries for that purpose.

I applaud you for wanting to do the slab once and right, as tear and redo later is expensive as hell and a real inconvenience.

Brian said:

While we are talking this, I would really like to know the cost of 4" and the difference per foot to 6".

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Brian- You make a good point in that if it's only the incremental cost of the 'crete', it's probably not the place to 'cheap-out'! In my structure at 28X40 the difference is about 7 cuyds, (13.83 cuyds, vs 20.74 cuyds). Figure what, $110.00 a yd, on the truck?

Mjn- I understand the 'bars, and chairs', but think I'm about to face Rebar sticker-shock! I've found this site helpful, http://www.concretenetwork.com/ especially the calculator. Looks like I've got a lot of reading to do! Thanks Guys! ~Scotty

I applaud you for wanting to do the slab once and right, as tear and redo later is expensive as hell and a real inconvenience.

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Well here my deal, I'm in a deep frost area, (except for this year) So I guess the slab will 'float' to some extent. So is the game plan: Packed soil, Geotec. Compacted stone, FoamBoard, Poly, Chairs and rod. and pour? Just trying to learn without my lazy butt doing all that reading! :laugh: Besides, Someone told me that there's a football game on today.....~Scotty

Brian-Here's where I am............

Brian said:

Are you pouring a foundation or doing a pole building or?

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http://www.greentractortalk.com/forums/showthread.php?1687-28-x40-Pole-Barn-Day-one!/page7

(Maybe post 62?) ~Scotty

What I know about concrete would fit in a thimble!

So I read a lot, and asked questions. I wanted the rebar and chairs also but everyone I asked about it locally wanted LOTS more money to do it. So when I had the pole barn built, I just lets them do it how they wanted and where used to-I did specify a vapor barrier and the 2" rigid foam insulation to keep condensation at bay. I think the base has a lot to do with the slab not cracking, like a good amount of well packed stone. Both of the pours for my pole barn have held up perfectly so far. I also agree that saw-cutting control joints is the way to go...I filled some with concrete caulk from Home Depot.

Scotty370 said:

Mjn- I understand the 'bars, and chairs', but think I'm about to face Rebar sticker-shock! I've found this site helpful, http://www.concretenetwork.com/ especially the calculator. Looks like I've got a lot of reading to do! Thanks Guys! ~Scotty

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Neat web site there, thanks for posting! Yeah, rebar can get pricey. I don't know if there is much difference in cost between the 40,000 PSI and 60,000 PSI rebar. For your purpose, I'd bet 40,000 PSI would be more than adequate.

Are you going to do your owning forming, etc and let Jose and the boys do the crap work of actually pouring, floating, and finishing the concrete? The more you can do yourself, the more you can save; but there is no way I would do the actual concrete pour and finishing as that is miserable work.

Floor Concrete continued.............

Mjn/KennyD- I envision that I'll try to do just as much as I possibly can! I.E. Form, stone, compact, wire or rebar, (probably wire, just for expense) and (in my area) have Tony and Mario, just come in and pour/float and finish! No way am I'm doing that! It's bull work, and a special talent that I have neither strength or talent for! I'm up in the 'air' on the Styrofoam, and I don't know if laying plastic film on the compacted stone buys me anything, but that's a cheap item in the scheme of things. I don't think I've got the humidity problem that you, Ken, may have in MD., But I see the 'wicking' issue might come into play, and make it worthwhile.

I think it will be: Geotec, stone, poly, and 6" 'crete', and be done! Kenny, did you use Geo-Tec fabric? And did they run a tamper over your stone before the foam placement? At any rate, sounds like you're happy! :thumbup1gif:
I really want to have this whole thing prepped so they can come in, 'spill the mud' surface and be out! Is one day asking too much if I've got it all ready? Thanks for you're continued input, guys! ~Scotty

Will toss in a picture of my attached shop. Ready to pour. You can see the drains as well.

I've got a thread on my outbuilding here, check it out for the concrete stuff.

Doing your own rebar is pretty easy. For my 30 x 40 tractor garage where I planed to do minor repair work, I had 3/8 rebar every 24". Total cost, including the deliver of the 20' rebar, was around $500. For my 24 x 30, I just got the 10' pieces of 3/8 rebar from lowes. This was a storage building, so I just rebared the front half. The goal was just to make sure that if things cracked the did not move. Spent about $100. IMHO, you at least want rebar by edges where you might drive something in to keep that area from cracking. There's a thread on that building here too you can check out.

Both pads had wire mesh in the hopes that minor cracks would stay that way. A concrete guy talked our fire dept. into using just fiber fill mesh for an 8" deep apron. In a year it was cracking.

Ground prep is region specific. Here in NC it's 4" of gravel on bare clay. Both my pads are minimum of 5.5" just so it's a 2x6 for the form. Note also that you want the rebar at or (Preferably) just a bit below the center of the pad, so a thicker pad makes it easier to get the rebar in the right place. Find out the incremental cost per yard of the concrete and do the math- it's easy to figure out the extra cost.

Once you see what compacting the gravel does, you'll always compact. It's $45 for a half day rental of a vibratory plate compactor. Around here they put down plastic. The contractors put down 4 mil. I come in after they do that and put down my own 6 mil. Then, as people walk around on it for both the rebar install and the pour, there are no holes or tears.

Agree on cut slots to avoid "caster disaster" syndrome.

At the end of the day, if you spend an extra $400 to $1000 on your slab for compacting, better plastic, some rebar, and at least 5.5 inches of depth you'll be happy.

Pete