Thank you. 4” it is.
That's 4" below final grade, if the slab is at least 4" thick and extends at least 6" beyond the PVC conduit. In other words, if such a 4" thick slab is the final grade, the PVC could be touching the bottom of the slab.
Thank you !
I have NEVER had a problem with pipe in a slab.
Ditto
I was replying to the statement "the PVC could be touching the bottom of the slab'', not that your electrical will 'have problems. Most, including experts here don't know that pipe 'touching the bottom of the slab' is a controlled contraction saw cut. The concrete industry says pipes should be embedded a minimum of 1.5" to prevent such issues.
That is addressing when conduits are embedded in the concrete, not under it. When we installed conduit in slabs (embedded) we tied it to the bottom the best we could.
I agree that if the conduit sticks up above the rest of the concrete substrate, then it will create a region of reduced concrete thickness, which may show up as a surface crack. I would refer to that as "partially embedded in the slab." By "touching the bottom of the slab" I meant that the conduit would be flush with the substrate on top, so there would be no reduction in slab thickness.
The topic in the article I provided is about contractual cracking. The part about embedding is a continuation of the topic of concrete cracking and embedding prevents it from cracking where the pipe or rebar is placed because it's embedded. Those experienced in stone work know that to break sandstone and even block, all one has to do is lightly score the surface from end to end and then hit the two ends with a hammer and it will break in two, following the scored line exactly. Less than a 1/128" mark and i can break a 6 in slab using a hammer. Believe what you want.
What's that got to do with the topic at hand? Relief cuts (expansion joints) are deliberate weakening cuts to allow a crack below the surface, (under the cut) they are intended to be a strategically located crack.
