Floor box in concrete slab

[joedreamliner787]

I have a few of the FBBOX-GY floor boxes going in. This is my first time doing it for a concrete slab. The slab on grade assembly is dirt - 4 inches crushed gravel - 2 inches XPS foam - 6 mil vapor barrier - 5" concrete slab - sika sealee ans finally a 3/4 inch hardwood floor. For the floor outlets does my sch40 need to be in the dirt or can I place it on top of the dirt so it's withing the 4" of crushes gravel? Not sure what the best practice is. Thank you

 

[rc/retired]

Yes, you can lay the pipe on the dirt.

Ron

 

[infinity]

Since the concrete is 5" thick you would run it in the concrete or in a chase in the concrete that gets patched if the concrete is already poured.

 

[joedreamliner787]

Yes, you can lay the pipe on the dirt.

Ron

Thanks Ron, the dirt is compacted so I'll put some rebar down close to the boxes and the stub up so it stays straight for the where it's going in the wall. Site is trenching for the plumbers Monday.

 

[joedreamliner787]

Since the concrete is 5" thick you would run it in the concrete or in a chase in the concrete that gets patched if the concrete is already poured.

Thank you. It's new construction slab and gravel hasn't been done yet

 

[infinity]

Thank you. It's new construction slab and gravel hasn't been done yet

Then I would just lay the conduit on the stone or if there is mesh or rebar on top of that. The box will be near the finished surface of the concrete so IMO there is no reason to run the conduit in the dirt.

 

[joedreamliner787]

Then I would just lay the conduit on the stone or if there is mesh or rebar on top of that. The box will be near the finished surface of the concrete so IMO there is no reason to run the conduit in the dirt.

After the vapor barrier is installed concrete contractor will be installing 6X6 X W1.4 X W1.4 WWF reinforcement prior to the pour. I didn't know I can run my PVC over the top of the mesh. Thank you

 

[curt swartz]

After the vapor barrier is installed concrete contractor will be installing 6X6 X W1.4 X W1.4 WWF reinforcement prior to the pour. I didn't know I can run my PVC over the top of the mesh. Thank you

Do not install anything on top of the mesh. Mesh gets dropped in then lifted up as the concrete gets poured,

 

[MattG0311]

I’ve seen situations where conduit was placed on top of gravel or relatively close to the surface of pours. It creates a weak spot in the slab and can cause a crack. Not saying it’ll happen in every situation but I prefer to run under the gravel.