Rebar

[Mark-Ia]

Steel or Fiberglas rebar for shop floor? What have you used?

 

[Janicholson]

I would use epoxy coater #4 steel rebar, and fibermesh concrete. I would use a 6 inch thick pour. Jim

 

[urbancase]

I would use epoxy coater #4 steel rebar, and fibermesh concrete. I would use a 6 inch thick pour. Jim

I did the same, only front section is 12 inches. I know it’s over kill but heavy equipment work at the time I figured it was a good idea.

 

[caterpillar guy]

Steel of one version or the other. No fiberglass for me.

 

[marloweg]

Steel or Fiberglas rebar for shop floor? What have you used?

no glass did one floor with it never again if your in cold part of country you will find out fast why all kind of pops from water going in and freezing little pop outs all over

 

[jwal10]

Depends on size of shop and what will be in it. I used #4 steel on outside approach and just inside the door for 6', 4' wider each side of the door, wire mesh for the rest. 2"x6" form boards. Biggest tractor was a 4640, loaded 7700 combines, loaded semi's....James

 

[caterpillar guy]

My floor is 6 inches for loaded semis at the time along with 8 inches on the apron in front. Thought it might need more with wet and frost as well as more loads of varying sizes. Has been there now almost 30 years. Cutting concrete is a joke it still cracks where it wants to. I would never cut a floor again for that. My floor was not cut nor cracked but the apron has cracked right corner ways of the cuts I didn't really want in it. It could be moisture since it is outside or it could be just being outside with frost. Still cuts are tough to roll a creeper on.

 

[MarkB_MI]

We have fiber mixed in the concrete of the parking area and sidewalk around our garage, and it was not mixed in well. Chunks of it pop out from time to time. I would never use it again; I'd use either steel or nothing.

Steel mesh works well, IF you're careful to pull it up as you pour concrete over it. Otherwise it will lay uselessly at the bottom of the slab. I used steel mesh in my shop floor and have no cracks after 20+ years. If I were to do it again I'd probably use rebar rather than mesh.

 

[Scott 730]

Still cuts are tough to roll a creeper on.

You will never know you are rolling over a saw cut with a creeper. Tool cuts are a different animal.

 

[rmcky]

I used #4 rebar (1/2 inch) every 2 feet each direction, and tied at every intersection, and placed on chairs to make sure it was in the correct location in the concrete. Six inch floor thickness, and 1 foot in the entry door. Do not use rebar if less than 6 inches thick. The floor was saw cut and no other cracks, in place for 19 years.

 

[mechanicfred]

I use #4 on 2 foot centers and cut at 10 foot squares. Never had any uncontrolled cracks.

 

[Not db4600]

I used #4 rebar (1/2 inch) every 2 feet each direction, and tied at every intersection, and placed on chairs to make sure it was in the correct location in the concrete. Six inch floor thickness, and 1 foot in the entry door. Do not use rebar if less than 6 inches thick. The floor was saw cut and no other cracks, in place for 19 years.

What is the correct location in a 6” slab?

Why shouldn’t I use rebar in a floor leads than 6”?

 

[MKinON]

What is the correct location in a 6” slab?

Why shouldn’t I use rebar in a floor leads than 6”?

I'd suspect because it's difficult to get good placement in the slab, especially if you're using 1/2" bar (1"where they cross). If I remember correctly, it should be between1/2 way and 2/3 up in the slab, with minimum 1-1/2" coverage. Our floor has 1/2" bar every 12", both directions, 6" thick and 8" thick within 18" of the edge all around.

 

[MKinON]

My floor is 6 inches for loaded semis at the time along with 8 inches on the apron in front. Thought it might need more with wet and frost as well as more loads of varying sizes. Has been there now almost 30 years. Cutting concrete is a joke it still cracks where it wants to. I would never cut a floor again for that. My floor was not cut nor cracked but the apron has cracked right corner ways of the cuts I didn't really want in it. It could be moisture since it is outside or it could be just being outside with frost. Still cuts are tough to roll a creeper on.

I would bet there are cracks in that floor, but they're only fine hairline and hard to see, probably because they're on a very solid base and/or not heavily loaded. Clean it well, hose it down and let it start to dry up, then you'll see them because they'll dry last. That is if it's bare concrete, not painted. It's concrete's nature, that's one of the reasons why it needs reinforcing.

 

[Not db4600]

I'd suspect because it's difficult to get good placement in the slab, especially if you're using 1/2" bar (1"where they cross). If I remember correctly, it should be between1/2 way and 2/3 up in the slab, with minimum 1-1/2" coverage. Our floor has 1/2" bar every 12", both directions, 6" thick and 8" thick within 18" of the edge all around.

I can’t recite ACI or ASTM, but the standard was 1-1/2” to 2” clearance from earth in footings and foundations. Slabs typically saw the rebar placed in the bottom third.
We just poured an 8” shop floor for a government job and the engineer wanted the reinforcement (#5, 16” OC EW) 2” from the TOS.
We’ve seen a trend to center and upper half placement of rebar. I don’t know who is teaching this. The integrity of a SOG has as much to do with soils and base under the slab as it does with reinforcing.

Let’s also understand that this new eco friendly green ground limestone powder and all the happy juice additives they are putting in concrete today is promoting shaling and cracking more than the portland concrete grandpa and uncle Tony poured in 1922 and even more than what we poured in 2023.

 

[MKinON]

I can’t recite ACI or ASTM, but the standard was 1-1/2” to 2” clearance from earth in footings and foundations. Slabs typically saw the rebar placed in the bottom third.
We just poured an 8” shop floor for a government job and the engineer wanted the reinforcement (#5, 16” OC EW) 2” from the TOS.
We’ve seen a trend to center and upper half placement of rebar. I don’t know who is teaching this. The integrity of a SOG has as much to do with soils and base under the slab as it does with reinforcing.

Let’s also understand that this new eco friendly green ground limestone powder and all the happy juice additives they are putting in concrete today is promoting shaling and cracking more than the portland concrete grandpa and uncle Tony poured in 1922 and even more than what we poured in 2023.

The more I think about it, I think the minimum coverage of steel is X times the thickness of the rebar at the very least, but I'm sure there are other factors that engineers would consider. I remember that most any of the jobs we worked on it was always at least 2" from the bottom and 2" from the top if not centred, especially if there was more than one layer of steel. I definitely agree about the importance of the underlying base integrity.

 

[Geo-TH,In]

Steel or Fiberglas rebar for shop floor? What have you used?

I use a concrete finisher. He likes wire and 6 inch thick floors. No cracking,
I have a garage floor. 4 inches thick and someone used rebar. MISTAKE.
The concrete cracks at the rebar, every 2 ft.
One pole barn builder likes fiberglas. Mistake, it cracks too. NO thanks.
I use a lifetime concrete finisher. He knows what he is doing.

 

[rmcky]

If I remember correctly, in a 6 inch floor the rebar should be centered in the pour, (concrete 2 1/2 inches above, 1inch where they cross, and then then 2 1/2 concrete below the rebar). If the rebar is too close to the surface or base of the pour, concrete will crack. I passed the concrete class, but that was 58 years ago........so no warranty.

 

[JIM MN]

Whatever you do, use expoxy coated rebar or coated wire mesh. Why? any metal sealed in concrete will rust away. Also, would use the fiber mesh concrete if the cost is in line? Plus, I would put in a floor drain.

 

[Not db4600]

Whatever you do, use expoxy coated rebar or coated wire mesh. Why? any metal sealed in concrete will rust away. Also, would use the fiber mesh concrete if the cost is in line? Plus, I would put in a floor drain.

I’ve seen a lot of concrete demoed and don’t necessarily agree with “any”. Seen plenty of mesh, bar, and embeds that are still in good shape. Granted there are plenty of instances where it is not in good shape. If it is incased and sealed it should be ok.
Where it comes to is exposed to moisture or salt it makes sense.
In 94 I was in the Whitefish Bridge. Sub grade foundation and bridge deck were epoxy. The vertical structure were not epoxy.

Currently on an Armory. Subgrade foundation and above grade vault are not epoxy. All CMU reinforcement is not epoxy. 8” civil paving is not epoxy. Mechanical mezzanine wire mesh is not epoxy on galvanized pour deck. The maintenance garage and aprons are epoxy.

Tomorrow when then excavator starts demoing the existing civil paving he might wish it had rusted away.