Concrete wire mesh chairs

[rburke65]

Ok concrete gurus.....Getting ready to have a shop/garage floor placed/poured around Labor day. I'm doing the prep work, the base is clay that was brought in and it is hard! I wanted to use plastic chairs to elevate the wire mesh but I'm getting prices of more than $300 just for the chairs. Looking for alternatives. A neighbor wondered if we took 1 1/2" or 2" PVC drainpipe and cut them into 2" pieces and used them. He has a lot of the PVC pipe he would donate......he owns a golf course construction company.... What are the forseeable problems with using the PVC rather than the chairs. Seems to me they are pretty close to being the same. The 2" pvc is large enough to fill with concrete?... Your thoughts, ideas, suggestions are welcomed. Thanks.

 

[Cryptic1911]

you can use anything, it's not going to be supporting any weight. It's just there to keep the mesh from dropping. Ours has slices of brick under it

 

[alk1174]

Just dont use anything that will rot such as wood.

 

[Falcon67]

So you need 1500 chairs? I see bags of 20 for $4 on Amazon. Here they are $167/1000 :http://craigsconstructionspecialties.com/product.php?id=3

 

[zporta]

How big is the garage?

Take brick or block and break them up to prop under the steel where it intersects

 

[billydotcom]

A few factors involved, but I believe the PVC pipe will do the trick - what size is the wire mesh? How big exactly is the wire diameter (Measure Guide: http://www.bwire.com/index.html )? Is it heavy stuff? Do you need something substantial to hold this mesh off of the surface due to the heavy wire diameter? If not....go with the PVC. Or - I would buy those little Plastic Rebar / Wire Cloth Supports as listed by a user a few posts up from here -

Try ther PVC first - FREE is best!

 

[rburke65]

The garage is 1800 sq. ft. 32'x56. Internet recommends about 900 chairs. The wire meshes 6"x6"......10 ga.

 

[brownbagg]

DO NOT USE RED CLAY BRICK, its against code because when they get wet they will crumble leaving a void. Only the gray brick is approved for concrete chairs

 

[rburke65]

Do I assume that these are the "masonry units" like the same material that a concrete block is made?

 

[Old nogales garage]

On a wiremesh that size I've never had to use any chairs. Don't know if your building code ask for it, but if don't l just pick it up off the ground as I go. Just don't go to high because it's a pain pushing it down. Also check into a fiber mesh in the concrete insted of wire.

 

[joes169]

DO NOT USE RED CLAY BRICK, its against code because when they get wet they will crumble leaving a void. Only the gray brick is approved for concrete chairs

Do you have a link to back up that claim? The reason I ask is because most "red clay brick" will withstand centuries of weather exposure (look to the oldest masonry homes in the NE for example) and generally have a higher compressive strength than conventional concrete. Besides, if they were to "crumble & leave a void" where would the material go??? It's not a suspended bridge, it's a slab on grade............

 

[rburke65]

It is not required by code here. I am using wire mesh so I can tie my pex tubing to it. I want the chairs to hold the wire off the insulation, to put it where it will do some good.....but not too high where I have to worry about cutting it when we "soft cut".

 

[zporta]

All reinforcement should be in the lower 1/3rd of the slab

I prefer steel rebar over wire.

 

[BARN ONE]

On a wiremesh that size I've never had to use any chairs. Don't know if your building code ask for it, but if don't l just pick it up off the ground as I go. Just don't go to high because it's a pain pushing it down. Also check into a fiber mesh in the concrete insted of wire.

Thats what I have always done, when raking out the concrete hook the mesh and pull it up as you go.

Beer cans work to. lol

 

[brownbagg]

alot of engineer are getting away from pulling u the wire because it leaves void under the wire. to me that hard to believe but I have started seeing it in spec that wire must be on chairs. and then they have swap to the heavier wire

 

[ConCretin]

The reason engineers require supports rather than pulling the wire up during placement is that 99% of the time the wire ends up back on the ground. The last guys through are on the screed and they gotta stand somewhere. I'm sure some of you guys can pull it off but most can't or don't.

I've never placed a slab without supports whether the specs called for it or not. Sure it costs more money but it's a lot less expensive than ripping out a floor because a random core shows the steel sitting on the bottom.

 

[gb99]

The reason engineers require supports rather than pulling the wire up during placement is that 99% of the time the wire ends up back on the ground. The last guys through are on the screed and they gotta stand somewhere. I'm sure some of you guys can pull it off but most can't or don't.

I've never placed a slab without supports whether the specs called for it or not. Sure it costs more money but it's a lot less expensive than ripping out a floor because a random core shows the steel sitting on the bottom.

Reviving this thread as my garage and basement slabs will be poured soon. Where can I buy the concrete dobies (that seem to be the preferred support)? Links would be appreciated.

Also, my slab will be ~4” thick, so a 1-1/2 to 2” dobie should be sufficient? Thanks!

 

[ford33]

From a practical view, how are you going to get the concrete workers to move around a floor covered in 6x6 wire mesh placed on 2 inch chairs? Their boots will not fit in the openings of the wire mesh so they will be crushing the mesh down to the ground or kicking it up in the air when moving. It will be a mess and they will be hating your job.

Why not go with a #4 or #5 rebar placed 12 or 18 inches apart and sitting on 1.5" chairs. You will likely get a better and faster job from the crew.