concrete help

[crewchief437]

ive researched and asked buddies on my foundation prep, pour and reinforcement and everyone has different opinions. my dirt guy is cutting into the hill and compacting. he has done dirt work all his life and says this will suffice for a good compacted surface. i trust him hes a family friend. secondly this is a 40x30 pole barn with the slab poured after installation with 4" slab 14"x14" footing around the slab with the poles sitting in 14"x36" caps in the footings. they were going to do fiber but i think im going with mesh and rebar instead. my questions are 1. Do i need to do sawcuts? The guy doing the concrete doesnt believe its necessary. 2. what level of reinforcement do i need. im looking at doing 6x6x6x6 panels of mesh with 3 strands of #4 rebar through the footings. one friend has heavy civil background so he wants me to put 10k of metal in the floor. i want to do this thing right. i understand there is not doing enough and there is doing overkill. i want a product that will last but not a slab that will sink me for money. Thanks for the help, Adam

 

[kd3pc]

the dirt needs at least 4-8" of gravel and a vapor barrier then what ever steel you are throwing in.

As to the cuts, if your concrete "guy" doesn't believe in saw cuts, I would either find a new concrete guy or KNOW that the pour is going to crack, possibly a lot on that size.

As to the steel, what is the floor going to be used for, and what is going to drive on it. Big difference between a wood shop and a tractor/heavy trucks....I would likely go to 6" over all, just in case. My 22x24 is only 4" but it was never intended to do major car stuff in it. I have 4" of stone on top of the compacted soil (clay/fill/etc) and almost 6" gravel on top of all that.

YMMV

 

[Tronyadorable]

ive researched and asked buddies on my foundation prep, pour and reinforcement and everyone has different opinions. my dirt guy is cutting into the hill and compacting. he has done dirt work all his life and says this will suffice for a good compacted surface. i trust him hes a family friend. secondly this is a 40x30 pole barn with the slab poured after installation with 4" slab 14"x14" footing around the slab with the poles sitting in 14"x36" caps in the footings. they were going to do fiber but i think im going with mesh and rebar instead. my questions are 1. Do i need to do sawcuts? The guy doing the concrete doesnt believe its necessary. 2. what level of reinforcement do i need. im looking at doing 6x6x6x6 panels of mesh with 3 strands of #4 rebar through the footings. one friend has heavy civil background so he wants me to put 10k of metal in the floor. i want to do this thing right. i understand there is not doing enough and there is doing overkill. i want a product that will last but not a slab that will sink me for money. Thanks for the help, Adam

Red clay or black dirt ? If it's dirt you need to compact a layer of crusher run over it.Add fiber to the mix.It wont slick up as well when finishing but you can address that later.

 

[crewchief437]

the shop will be used for some car stuff but nothing serious. heaviest vehicle in there will be a muscle car when i find time to buy and restore one. i am not putting a lift in or anything like that. from what ive been told from neighbors the native soil is red clay which is why i leaned away from bringing in fill and hadnt thought about bringing in gravel. as far as saw cutting i think i am going to do this ill just force them into it and they can deal with it. also i wasnt going to get fiber bc i had read someone that said it messes with epoxies and sealers. if it doesnt ill probably go with metal and fiber.

 

[Tronyadorable]

the shop will be used for some car stuff but nothing serious. heaviest vehicle in there will be a muscle car when i find time to buy and restore one. i am not putting a lift in or anything like that. from what ive been told from neighbors the native soil is red clay which is why i leaned away from bringing in fill and hadnt thought about bringing in gravel. as far as saw cutting i think i am going to do this ill just force them into it and they can deal with it. also i wasnt going to get fiber bc i had read someone that said it messes with epoxies and sealers. if it doesnt ill probably go with metal and fiber.

Nevber used epoxies. I suppose you best email the engineers at the manu. you plan on buying your final finishes from. That and maybe call the cement plant for the type(s) of fiber they offer.I know Rinker would sent a guy out to talk with you about prep and recommend what to do.
Check with your closest plant.

 

[Rookie2]

Every concrete guy I asked before I poured my 40 x 60 x 5" said it will crack ! So I cut it into about 14' squares (12) pieces. I only used fibermesh and added hydronic heat. Yes I have one crack about 18" at the garage door to the floor drain. 1) roll and compact till you run out of fuel ! Don't pour around any square pilasters , use some type of cure and seal or keep it wet for several days. There are a lot of info on this site , do a search, plenty of concrete guys will chime in !

 

[tomd]

What state are you in?

 

[crewchief437]

southern Mississippi

 

[BigGMC]

To do it again, I would omit the fibers. After finishing they stick up above the surface, so any coating you put on (paint/epoxy) will tend to pick them up and glue them in place vertically.
I havent coated my floor with anything, but I'm often rolling around on the floor working on things. I'm not super sensitive to the fiberglass, but I've heard of others who are.
They'll eventually wear off, but I'm considering renting a floor scrubber to try and sand them off.

chief - why the footers? A requirement for the type of soil in your area? Seems like with pole construction, you only hear of basic slab for floor, since the poles are supporting the wieght of the building, not the slab.

 

[NZ0J]

You need to find a new concrete guy. Any guy that says saw cuts aren't necessary has no business doing your job, or any other concrete job for that matter.

As far as reinforcement, if it were me, I'd go with rebar in the slab. But, if you choose to use your concrete guy, fiber might be the way to go. If he doesn't believe in saw cuts, he may not believe in pulling up the rebar as he pours either, hate to see all the rebar go to waste by laying on the bottom of the slab, at least the fiber would be integrally mixed into the concrete.

 

[BlackTalon]

WRT fibers sticking up out of the slab, you can burn them off. No need to wait until they wear down.

 

[crewchief437]

i assume the larger footing and pillars are to help support the weight of the slab to reduce settling and cracking. what type of foundation do most people do on a pole barn in reference to footings for my size slab?

 

[Creative Fab]

You can use Zip Strips vs saw cuts, only a fine crack will appear after it cures for a while. These fine cracks will be in a perfectly straight line, that is if you place them in that straight line during the pour.

 

[crewchief437]

has anyone here used the zip strips? they seem pretty neat and useful

 

[James-W]

I never heard of Zip Strips. Is this something new?

 

[c39er]

Zip strips are clean and neat. Mine were done over 20 years ago and you cannot see them under a very tiny crack line...
Of course requires a good concrete guy.

 

[cbracer]

wow sounds like you're going overkill on it. Mine is compacted soil, 2" compacted base fill (stones & little dirt), no vapor barrier (i live in southern CA) and 4-5" of 3500 psi concrete with wire mesh held into the center with stand offs (not pulled up while pouring). If you do rebar you need 5-6" thick. I would highly recommend 3500 psi. If you go 4000 it will get too warm during the cure and you'll have small cracks. And if you do a vapor barrier with 4000 psi it can warp. If you can, compact the soil and base 12" out of the pour area so you don't end up with a corner that sets down and cracks. Happened to my neighbor's driveway. Depending on the slope of the land, you need saw cuts every 4'x4' worst case to 10'x10' best case.

 

[Ch3No2]

Most Civil Engineers I know believe wire is worthless...even when it gets picked up. They all seem to believe #4-16" on center both ways is the best...and you can put it in a 4" slab. Any good concrete guy recommends saw cutting within 24 hours of the pour.

 

[c39er]

Saw cutting leaves a kinda not so clean looking 1/8" line doesn't it?

 

[LennyTheLizard]

My concrete guy is pretty well thought of around these parts.
He told me, he would give me 2 guarantees: The concrete will get hard, and it will crack.
For some reason, they put zip strips in the basement portion, and I have a nice fine, straight hairline crack down the center of floor.

Upstairs on suspended floor and floating floor, they did not put in the zip strip or make saw cuts, and there are cracks all over the place! Guess I was supposed to do it afterwards. Also, may have been some fear of interfereing with the water lines for radiant heat.

 

[Bsj04]

Why a 14x14 footer and a pole barn? Usually the "poles" hold the load so there is no need for a footer in the slab.

 

[crewchief437]

to sustain the weight placed on the slab and prevent settlement is my understanding