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Chebanse, IL..... | Do you think it makes a big difference in the longevity & performance of the finished product on a smooth cement floor with embedded pex piping on insulation sheets for heat as to whether you use re-rod or 6 ga wire mesh for the reinforcement?
Any proof as to which is better?
Thanks |
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Sac & Story county IA | I like a lot of small rebar. That is just my experience tearing out old work. The mesh gets stepped to the bottom of the concrete. With rebar on chairs, there is room for feet of people doing the placing of the concrete. With mesh, there is not. |
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Washington Co Ks | My dad worked on construction jobs when I was young and I remember him telling how they had notches cut into their shovels to hook the mesh and pull it up into the concrete but if the inspector wasn't there a lot of it was on the bottom. |
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central - east central Minnesota - | The proof you are looking for is in engineering books and look at commercial jobs.
Rebar is for strength there is no mesh compareable to rebar . . . .
Rebar offers shear control where as mesh does not.
Use of the floor would make a difference. If it's a home owner city garage floor, no rebar maybe neccessary - if it's a shop floor where loaded trucks would be parked /worked on then rebar . . .
Preparing the base for all concrete is the key - most important step to crack free concrete, for all projects.
There is a company here, in Mn, that offeres a 5yr warrenty - to crack free concrete or they'll tear it out and replace, free.
The contractors that use there concrete have to be cetified, by Cemstone, or no warrenty. The key step to their warrenty - base preperation.
Edited for clarity. . ..
Edited by iseedit 4/27/2012 08:25
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Morris, IL | Rebar, make them cuss when they take it out. Guy we hired to pour and finished our concrete said he has never tore any concrete out that had mesh that wasn't on the bottom or close to it. |
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Maine | iseedit - 4/27/2012 07:28
....If it's a garage floor no rebar neccessary - if it's a shop floor where loaded trucks would be parked /worked on then rebar . . .
I would say for the small cost of rebar in the grand scale of things, why not use it on a garage? My FIL's garage has none and its a complete disaster...You couldnt roll a tool chest from one side to the other no matter how hard you tried...
I've been getting quotes to pour my 30x50 Garage and I will be putting in #4 Rebar all over... 12" spacing around the perimeter, and 18" on the inside...overkill, probably, but I dont want to pour 2 slabs over the small cost of Rebar. |
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| Ron, I have a friend who's amily was in the concrete business for 50 yrs or more. A one time they owned 7 or 8 ready mix plant. Him & his dad always claimed that you didn't need rebar or mesh if the concrete was done right. They always said that if concrete is going to crack it will crack whether it has rebar or not.
I guess I'm old fashion as I like plenty of rebar myself. However, the crew that poured my shoop floor in 2000 & the one that poured the new shed floor last fall both used mesh placed on chairs. When pouring the concrete they had a guy with a long hook that went along & pulled the mesh up as the concrete was poured. Both guys have been in the business for years & are the highest recommended in this area. First guy did most of the concrete work @ Purdue U for years & has done many industrial complexes, including the CAT plant in Lafayette, IN.
There is one small crack, maybe 4" long, in the shop floor that was poured in 2000 in a corner running from saw line to saw line.
Edited by boog 4/27/2012 08:26
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| Have to agree with everyone else, however improper wire placement is the fault of the installer. Application determines not only the need for steel, but the concrete mix as well. I tend to use more (steel and cement) than required, just to be safe. Would rather do it right the first time and not fight it again. Sometimes that means both, but always some bar. |
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central - east central Minnesota - | Spudland_Dave - 4/27/2012 07:10 iseedit - 4/27/2012 07:28 ....If it's a garage floor no rebar neccessary - if it's a shop floor where loaded trucks would be parked /worked on then rebar . . . I would say for the small cost of rebar in the grand scale of things, why not use it on a garage? My FIL's garage has none and its a complete disaster...You couldnt roll a tool chest from one side to the other no matter how hard you tried... I've been getting quotes to pour my 30x50 Garage and I will be putting in #4 Rebar all over... 12" spacing around the perimeter, and 18" on the inside...overkill, probably, but I dont want to pour 2 slabs over the small cost of Rebar.
Sounds like rebar or mesh wouldn't help your FIL's floor .. . . the base is key.
As someone points out, a guy can get by with no metal - but the key is base preperation, for the concrete to sit on.. |
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Maine | iseedit - 4/27/2012 08:27
Sounds like rebar or mesh wouldn't help your FIL's floor .. . . the base is key.
As someone points out, a guy can get by with no metal - but the key is base preperation, for the concrete to sit on..
This is true...lots of clay on the lot and they cut corners back in the day when it came to fill.....BUT at the same time, with Re-Rod, the concrete wants to stay together and actually lay flush even if cracked...so you could roll a toolbox from one side to the other. We have a storage garage built in a swampy area with alot of frost action...one spring I saw an entire corner of the garage 4" above grade (plain floating slab)...that slab is still nice, but its loaded with Re-Bar. I doubt it would be as nice as it is without the Re-Bar.
The way I see it...Re-Bar gives you some additional help and fudge factor you can use to compensate for all the other variables in pouring the slab like Correct Base, Concrete Mix, Curing, etc... If Re-Bar were priced like gold, I'd certinaly change my position, but with being as cheap as it is, IMO i cant see why you wouldnt want to use it. In a perfect world as mentioned...perfect base, perfect pour, perfect curing & finishing, you guys are absouletly right..probably dont need any. When was the last time you saw everything being perfect? |
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Kingston,Mi | 10 Gauge wire mesh on at 6 inches by 6 inches is nothing more than a handle to throw broken concrete when it gets torn out. I have supervised the use and installation of 10's 0f thoushands cubic yards of "urban riprap" for conservation practices and wire mesh has sand on one surface and concrete on the other. Pulling up wire mesh while standing on it is quite a feat of antigravity.
1/4 inch welded wire panel on chairs would be different and more likely to remain in place if enough chairs are used and properly sized and spaced rerod would be best.
Without a firm compacted base, all will fail to some extent.
Roll wire(wire mesh) does, however, make nice cages around trees during establishment. |
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| you have the option to know what every truck load of ready mix has in it, AIR and Temp , Slump at arival are the biggies when truck shows up.........
You can have (pay ) for some to be there and test evey load, that is when you will make the batcher honest...
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have plenty of good grunts on job site and lay the concreate out in a 2 slump, 4 and over slump will be rewarded with troubles ...........
the window for air test , 5.3 to 6.0 roughly , lower or higher are not so good......... air is very important as if it is in tollerance it will let the concreate flex with out cracking.....
just go watch them poor a fed or state bridge and see how anul every one is about what I have said here, I know , I have bacthed fed jobs.
And if you want the best when it comes to rebar, then get epoxy treated rebar, cause rust in side cured concreate is not so good for long term concrete.. just saying
Also, test have showed concrete can cure for 100-200 years.. |
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East Central Saskatchewan | Best rebar I have ever used is old diamond harrows, cheap at an auction sale, ready made steps to hold them in place, we used a vibrator to make sure they filled in properly. I agree with the cement testing, I helped pour a driveway of an engineer one time, he tested each load, made the truck sit and mix forever for some reason, the driver and company were mad, the guy said take it home it is not what I ordered. Eventually it got to spec and we poured it and got the beer drank. |
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just a tish NE of central ND | I would say for light loads like sidewalk..... mesh is ok if done right .Heavy use .. like a driveway or modern shop floor for heavy traffic and trucks needs rebar. A local guy here said mesh will stay in place if you put it in place with only hooks and lift it behind you as you exit the cement ONLY if the cement is thick and has enough rock in it to hold it up. If the cement is skimping on rock it and watery it will fall to the bottom. Then the mesh gets blamed for crappy mixture of cements faults. |
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SW MN and Gold Canyon AZ | Rebar no doubt. Everyhting Ive poured has rebar and I have very few cracks in any of it. Like some say ground prep is very important. After putting up my first machine shed I left it settle for 2 yrs before pouring concrete. I could not beleive how much it settled in those 2 yrs. Poured it knowing it would not settle much anymore but still put rebar in 2 ft squares and one ft squares where heavy loads drive on it. Very few hairline cracks in it after 2o yrs now. Concrete is something you don't skimp on.
Pretty hard to do it over if you make a mistake. |
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| In 1957 I excavated and poured a drive 130 feet long. I didn't have much gravel so it was poured nearly the full thickness of 1x8 form boards. It has rerod and wire mesh. It got truck traffic (tandem axle trucks) for the next 30 years. Last I checked 5 years ago, it hadn't cracked yet. It has cross seams every 10 feet with rerod connecting the slabs. That's in a St. Louis unincorporated suburb. My dad said it took real effort when the county widened the road and took out a slab or two. Their replacements have not weathered nearly as well.
In 1989 I prepared my new machine shed floor with packed sand (by my feet) fill to level it, and rerod plus mesh. It was sawn and has one crack but no offset at the crack. I specified 4000 PSI concrete I think. The crew wanted to know if I was going into the preparation business. They liked how it was done. There's a plastic film (silo cover) under the concrete too. Its about 5-1/2" thick.
With concrete over $100 a yard and #4 rerod under $5 a 20' stick rerod on 18" intervals doesn't add much to the project cost with labor costing as much as the raw materials.
Gerald J. |
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Pine City, MN | Like others said. The base is more important than rebar or wire mesh.. I know for a fact I rather jackhammer out a slab with rebar, over wire mesh that's in the concrete. If that equals more strength I'm not sure. We got slabs with wire and some with bar some with nothing and they all look the same to me. We run heavy semi's on them also. Again the base is the key. |
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NW Ohio,near Findlay | re-rod on supports, no comparison. Wire will not stay up. What a difference when tearing out. |
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Maine | Speaking of Supports, what does everybody use or reccomend? I've heard some people reccomend I use Pieces of Brick (break standard bricks into 2-3 pieces) and a couple have reccomend I use chairs...one said plastic, the other steel....
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NW Washington | I will pile on about the importance of a firm compacted base and that the concrete is a good strong and relatively dry mix. Too much water and improper finishing will ruin the job regardless of how much steel you put down. Then stress joints need to be sawn or put into the slab. Fiber in the concrete mix helps too. Then the concrete has to cure properly, which usually means slowly over several days.
Rebar mainly controls cracks. And rusting rebar is one of the primary ways that concrete ultimately fails. The Roman concrete dome of the Pantheon in Rome is going on 2000 years old and it has no cracks and no rebar and I think it is a 142 foot span.
http://en.wikipedia.org/wiki/Pantheon,_Rome |
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Kingston,Mi | We used bricks nearly exclusively, but they are a concrete brick designed for use in concrete. Clay bricks are verbotten and I have had crews really not happy with me when I had the land owner ask that be replaced or the government money walked of the site. |
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Chebanse, IL..... | What diameter is 6 ga wire mesh?]
This would be on chairs. |
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Chebanse, IL..... | Gerald
You seem good @ math. So, how much re-rod would it take for 2 floors. One would be 80' x 80', the other 16x30. Consider 2 different spacings, 12" & 18". I believe it would be either 1/2" or 5/8" re-rod, though not epoxied.
Thanks |
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Chebanse, IL..... | #6 wire on chairs will not stay up? I'm not arguing, but just making sure I understand your statement.
Thanks |
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Chebanse, IL..... | So, you're saying either epoxied re-bar or no re-bar?
I assume there is no such thing as epoxied mesh? |
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| slightly bigger then no.9 wire........... |
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MI | 3/16" |
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| For 12" spacing it would take 79 each direction. Or 79 x 80 plus a bit for splicing overlaps each way. 158 x 80' = 624 pieces 20' long. 12,840 running feet.
18" spacing would take 2/3 as much, 416 pieces 20' long, 8, 560 running feet.
Gerald J. |
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Chebanse, IL..... | Gerald
Thank you!!!!!!! |
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Wire mesh or re-rod for concrete?
