There have been a few points on this topic already but I wanted to get clarity. I plan to install the pex tubing to the top of a 6x6 mesh as shown in the picture. The slab is 4" thick, I will be using 1/2" dia pex. My question is do I need to raise the mesh up off the insluation? What distance? The only way I have seen it done is with the mesh at the bottom of the concrete slab. Will this still add strength to the slab?
In Floor - Mesh Height
- Thread starter mk7880
- Start date
pstnbly
Well-known member
Mesh should be in the bottom 1/3rd of the thickness.
hidollartoys
Well-known member
When I did my slab prep I set the mesh on "slab bollsters(sp)" I pruchased from the local concrete construction materials supplier (not the concrete co).
Check out my build thread, there are pictures there.
Check out my build thread, there are pictures there.
Justanoldguy
Well-known member
If you leave the mesh on the bottom,
you may as well just leave it at the store.
you may as well just leave it at the store.
MScott
Well-known member
I am placing the mesh on top of the pex (which is stapled to the foam insulation.) This places the mesh almost 1 inch up into the foam and protects the pex from being cut when the concrete is scored. I debated putting stands to raise the mesh higher, but walking on it during concrete pouring would probably just compress it lower anyway.
Highbeam
Well-known member
My slab looks just like the picture. We tried lifting the mesh during the pour as is standard practice but it surely sunk down in places. If I could do it over I would have stapled the pex to the foam and then mesh on top of the pex. Steel reinforcement is not required in most cases.
The mesh will absolutely not protect the pex from being cut with the joint cutting saw. That saw will walk right through the mesh. Besides, the pex is near the bottom of a thick slab out of harms way.
The mesh will absolutely not protect the pex from being cut with the joint cutting saw. That saw will walk right through the mesh. Besides, the pex is near the bottom of a thick slab out of harms way.
tdkkart
Well-known member
My concrete guy told me the only good reason to put mesh in the concrete was if you had some mesh you needed to get rid of or hide, otherwise it's a waste of money. His explanation, which made sense, was that if there is enough force there to break concrete, do you think 12-16 gauge wire will slow it down??
Staple your pex down to the insulation, use re-bar to add strength.
Staple your pex down to the insulation, use re-bar to add strength.
Highbeam
Well-known member
Yes. 12 gauge wire, a whole bunch of em, is much stronger than concrete in tension. It will not only reduce the chances of cracking in the first place but also act to prevent those cracks from becoming seperated and heaved.
You do want it in the bottom 1/3 of the slab though. That's the biggest failure of mesh, improper installation which I am also guilty of.
hidollartoys
Well-known member
Yes, normal duct tape, just to hold it in place for prep and pour.. My mesh is 6ga., floor is minimum 6" thick. I would agree that mesh in a home shop floor is probably not required if the mix is correct and consistant from load to load. Metal (steel) in the concrete will make it less prone to failure.
I did not cut (stress reducers, IE control joints) the floor after pouring. My floor has some VERY small cracks but ALL concrete cracks. I am very happy with the final results. My concrete guy was a batcher at a large local concrete for 5 years and specified the mix. Used water reducer and fiber and checked each load "batch" specs prior to allowing it to be used.
Last edited:
Mk,
Looking into the same thing: how to did you conclude pex on top of mesh is best as opposed to the reverse ? Are you concerned the mesh on top of the pex might damage it during the pour as the mesh is walked upon ? Likely the pex will be walked upon and pushed into the mesh regardless ? Just trying to understand, thanks.
Justanoldguy
Well-known member
If the mesh is on top of the pex then you can assume,
at least the mesh is IN THE CONCRETE instead of sitting
on the bottom. That is a plus for sure.
OldGuy,
Yes, thanks, that's where I was going with that comment. I've watched them pour floors, they lift the mesh, then stomp all over it after doing so. You would think the mesh just goes right back to the bottom of the floor where it does no good
?! 1/2 pex will guarantee the mesh is in the concrete.OldGuy,
Yes, thanks, that's where I was going with that comment. I've watched them pour floors, they lift the mesh, then stomp all over it after doing so. You would think the mesh just goes right back to the bottom of the floor where it does no good
Upstate - My resoning behind putting the mesh below the pex was accuracy and cost. Zip Ties are really cheap and easy to put in. The Mesh is 6x6.. so I can accuratly keep the mesh at a 12" c-c distance in the runs. The 2" insluation board doesn't have any markings so I would have to measure and mark 12" c-c. The tool to install the plastic staples is over $250 at Menards.
Highbeam
Well-known member
I've never seen anybody attach pex to the mesh when the mesh is on top. In a pinch, you could just zip tie it but you'd have to fight it into position. I zip tied (at least 1500 ties) my pex to the top of the mesh. It's not just the zip tieing that will ****** your fingers, you then need to go back through and cut off the tails and be sure that you remove them so that they don't float up into the surface finish. Lots of labor but the grid of the mesh does make an excellent layout guide.
Rent the stapler.
Rent the stapler.
Highbeam
Well-known member
You either lift it up during the pour with your fingers as you screed back so that you give it the best chance to stay up in the concrete or you can elevate the mesh on dobies. Lot's of them.
If you plan to lift with your fingers, don't lift too far. You don't want the pex up too high in the slab to where you could cut it with the sawcutter.
pstnbly
Well-known member
Here's a typical garage floor I do in VT.
Grade and compact sub-base, install 6mil black poly moisture barrier overlapping seams 24" minimum.
Install 2" 250 eps foam.
Place 6x6 mesh overlaping at least 1 row.
Zip-tie 300' loops of 1/2" barrier pex to mesh 2 rows 4" on center around the exterior perimeter and 8" centers on the interior loops, no particular pattern just to fit.
Make dobies from suitable size concrete patio block (1 1/4" paving block for 4" pour)
Lift mesh, place homemade dobies on approx 24" centers.
Place concrete.
After placing and finishing floors for many years this method yields the best results for me. Having the tubing on the elevated mesh means it will be completely incorporated in the concrete for maximum heat transfer. Having the mesh at the proper height before placing means less confusion during the pour (I don't have to break concentration to remind the crew to lift the mesh). This takes a lot of stress away from a very stressful job.
Grade and compact sub-base, install 6mil black poly moisture barrier overlapping seams 24" minimum.
Install 2" 250 eps foam.
Place 6x6 mesh overlaping at least 1 row.
Zip-tie 300' loops of 1/2" barrier pex to mesh 2 rows 4" on center around the exterior perimeter and 8" centers on the interior loops, no particular pattern just to fit.
Make dobies from suitable size concrete patio block (1 1/4" paving block for 4" pour)
Lift mesh, place homemade dobies on approx 24" centers.
Place concrete.
After placing and finishing floors for many years this method yields the best results for me. Having the tubing on the elevated mesh means it will be completely incorporated in the concrete for maximum heat transfer. Having the mesh at the proper height before placing means less confusion during the pour (I don't have to break concentration to remind the crew to lift the mesh). This takes a lot of stress away from a very stressful job.
stingry
Well-known member
Good Grief!! Why do people insist on making this harder than it needs to be. Staple the PEX to the EPS (you can rent a stapler), place the mesh on the PEX and pour the concrete! You do not need to maintain exact 12" centers, you are warming the entire slab so a few inches either way makes no difference. The concrete has little or no resistance to heat transfer, the EPS is what resists heat transfer to the ground. By using the above mentioned method, you (1) know exactly where the PEX lies (2) know that the mesh is at least 1/2" off the bottom of the slab(where it needs to be) and (3) it's simple, straightforward and the concrete crew does not have to worry about the PEX! I installed my insulation, the PEX and the mesh, then the concrete crew came in and did what they do best, pour concrete!
Cheers
Steve
Cheers
Steve
stingry
Well-known member
http://www.blueridgecompany.com/hydronic/pex-tubing/pex-tools/311
This is where I rented mine. I used the $50/2 weeks model. It worked OK but at times it would jam. For the extra $10/2 weeks, I would try the other model, it may work smoother (or not!!).
Good Luck
Steve