Concrete in Pole Barn advice

[KWentling]

Agree with Eddie, but would add to cut control joints 1" deep in a 10'x10' or so grid. If there is danger of getting water in the joints and it freezing, fill them with SL caulk.

Kim

 

[MarkV]

I am no concrete guy either but understood that rebar in a 4" pour, which is usually 3 1/2" with 2x4 forms, is not thick enough to use rebar. I always thought rebar needed more than an 1 to 1 1/2" concrete around it to be effective. Anyone know what is actually recommended for thickness around rebar?

MarkV

 

[vtsnowedin]

I'm a highway construction inspector so have the build it good and stout point of view. We use 4 inches for sidewalks that carry pedestrians and bicycles and go to six inches at each drive where a loaded truck will cross. Bridge decks are 8-1/2 inches thick with TWO layers of rebar #5s or bigger on eight inch centers one way and 12 inches the other. Any place you can stick your foot down through to the forms is "Wrong".
No need for vapor barrier in a barn. Your not trying to keep the basement dry or radon gas out.
For a tractor that goes 7000 wearing its loader etc. I'd go with #4s on 18 inch centers each way held up 2 inches from the bottom by chunks of brick or similar well tied together. You want it near the bottom of the slab as that is what goes into tension when the load is applied to the top of the slab.
I'd use 4000 psi mix with a water reducer and then not pour it more wet then needed to screed it level. (That will be overkill in most peoples book but I'm OK with that) And I'd pour it six inches thick just to be for sure for sure. Just my $.02, good luck with your project.
Oh I'd consider leaving the six inch grade if it drains to the door as that will let snow melting off the tractor find its way out without a illegal floor drain.

 

[SPIKER]

I had an Amish Crew do mine came high recommended by neighbors and co workers 4 people all used same guy and all had great slabs/drives/patios and the like. I went ~5" with the main GD side closer to 6" where tractor or cars will come in and out. I put slab out in front and inside my pole barn. My barn was put up in Nov 2002 and the slab went in in Sept 2011. I took some videos and pics if you want to see

Note PUT IN the vapor barrier, cost less than 40 bucks to put down some top of line 6 mil plastic that size.

Mine has in floor radiant heat tube placed on 6x6 10awg steel mesh. It was put up on 1" plastic chairs on 2 foot grid to help keep it up into slab. I ended up having 60 yards & crew paid for concrete that I ordered. I had 6000PSI Mix With Fiber. I have 2" of styro-foam and radiant barrier insulation (foil bubble bubble plastic) under mine. The base was mostly clay, gravel and sand all compacted 10 years of settling so far only cracks are 2 hair lines on sides of roll up door and outside where cuts were made. I did not cut inside where heat tubing was



I have 5 pages of barn pics there so once ya see em you can keep clicking left/right for more.

Also be sure to add some under slab utilities service pipes if you have some now or not you will eventually probably want to run a wire or pipe or line in/out of the barn!



It is good also to keep the floor wet to help it hydrate & harden properly. If it drys out too fast it can be weaker than it should. The plastic under it helps this and spray on top after it helps this out after it has initial working surface. I kept mine wet for about a week inside the sealed up barn and it has some of the hardest chip resistant stuff I ever seen. I put STAIN on it that didnt even penetrate the floor 45 days after the pour & week prior to moving stuff back into it :/

One of hardest things was getting all my junk out and then having to put it all back in my clean pretty barn

Mark

 

[R_Walter]

You'll want to be sure to plan for a concrete apron outside the doors and access areas.

 

[KennyG]

I am no concrete guy either but understood that rebar in a 4" pour, which is usually 3 1/2" with 2x4 forms, is not thick enough to use rebar. I always thought rebar needed more than an 1 to 1 1/2" concrete around it to be effective. Anyone know what is actually recommended for thickness around rebar?

MarkV

The standard specification for any structural concrete is a minimum of 2" cover over the re-bar, so technically you are correct. However, for a residential/commercial slab, I wouldn't worry about the cover when putting rebar in a 3-1/2" slab as long as you can keep it reasonably well centered.

 

[paulharvey]

I'm a highway construction inspector so have the build it good and stout point of view. We use 4 inches for sidewalks that carry pedestrians and bicycles and go to six inches at each drive where a loaded truck will cross. Bridge decks are 8-1/2 inches thick with TWO layers of rebar #5s or bigger on eight inch centers one way and 12 inches the other. Any place you can stick your foot down through to the forms is "Wrong".
No need for vapor barrier in a barn. Your not trying to keep the basement dry or radon gas out.
For a tractor that goes 7000 wearing its loader etc. I'd go with #4s on 18 inch centers each way held up 2 inches from the bottom by chunks of brick or similar well tied together. You want it near the bottom of the slab as that is what goes into tension when the load is applied to the top of the slab.
I'd use 4000 psi mix with a water reducer and then not pour it more wet then needed to screed it level. (That will be overkill in most peoples book but I'm OK with that) And I'd pour it six inches thick just to be for sure for sure. Just my $.02, good luck with your project.
Oh I'd consider leaving the six inch grade if it drains to the door as that will let snow melting off the tractor find its way out without a illegal floor drain.

Agree for the most part. 6" 3000 psi concrete, wire, I personally like rebar. What I would add is if you form, grade, reinforce yourself, and only hire out the pour and finish you can save lots of $$$. As a note I am also a roadway/engineering inspector, but as a commericial construction superintendent we would often grade, form, reinforce, and buy the mud and just sub the pour/finish because for for roughly $750 you get a crew who can actually do the physical part. I like a light horse hair broom finish,

 

[Ken45101]

Around here they tell me that fiber is just as good as steel. IDK, but our driveway (1500' up a steep hill) was poured 40 years ago without steel (or fiber, I assume) and has held up very well, but they poured it 6" thick.

Extra concrete does add to the cost but shouldn't add to the finishing cost. When we did a new barn floor to handle the heavy campers, we did it with 6" and no steel.

 

[paulharvey]

The thing with any driveway (or anything you drive on) is if the base is good material, compacted well (typically 95-98% of maximiun density) the final wearing surface be it 4" concrete, 6" concrete, or any where from 1-2" of asphalt it will hold up well. On the flip side if you pour 6" of 4000 psi concrete with wire or fiber on uncompacted material, fat clay, or high organics it Will fail.

 

[bucktaker]

I have a 40x64 pole building that I store my Sundowner 4 Horse LG trailer 17k , 6600 lb boat and my in-laws 35 ft winnebago 12k all on 4" on fibered concrete control joints in a 10x10 grid with no issues of cracking or seperating. Its all about the base and how stable is is. I filled the majority of by building with bank run and allowed it to compact naturally by exposure and parking on the pad for two yrs then built the building and added 12 inches of limestone leveled and compacted, then my concrete. 6 yrs now no issues.