NM cable under joists.

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nizak

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Went to a residential renovation project today. GC is removing suspended ceiling from basement and going to dry fall spray the open floor joists.
Grid ceiling was original when home was built and all NM cabling was stapled to underside of joists. All home runs( continuous from point A to B) and the lighting circuitry is all on the surface.
The height to the joist bottom is 93". Will all these have to be pulled out of the panel and run through bored holes?
 
Unless you put the ceiling back up you would need to run the cables through bored holes or install them on running boards if they're smaller than 6-2 or 8-3 NM cable.
 
Your call which is easier, depending on how many of them are grouped together. You can slip a running board underneath (technically above the wiring) the cables. If they're all over the place, might be easier to pull them out and drill the holes.

Or you could add strapping on each side and cover them with sheetrock or pine.
 
Unless some inspector is going to require something be done with them, or if they are just such a mess that you want to clean them up by re-routing them, I'd just leave them as they are. They are still about as exposed now as they will be if you drilled joists or put a running board behind them. Above 6 feet doesn't normally see hardly any physical abuse - unless someone decides to hang things from the cables - which they may do anyway even if drilled through floor joists.
 
I have experience trying to make dryfall stick to romex.

It does not work. 150% positive it does not work. It just becomes a perpetual mess.

Makes good footprints though and they stick to anything.

I assume that this is not your concern but I thought I would share.
 
nizak said:
Went to a residential renovation project today. GC is removing suspended ceiling from basement and going to dry fall spray the open floor joists.
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luckylerado said:
I have experience trying to make dryfall stick to romex.

It does not work. 150% positive it does not work. It just becomes a perpetual mess.
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I agree with Lucky and whatever you are going to do make sure you are finished before the contractor sprays is stuff.
 
Instead of pulling all that wire out and drilling holes, you could just notch all the joists where the wires are and use nailplates to protect the wires. Be a whole lot faster.
 
Notching horizontal members should be treated differently from vertical members, based on engineering calculations. But the code may not explicitly recognize that.
 
A small notch on the bottom of the joist large enough for a wire to get tucked in is not going to make the house fall over! How big of a notch do you need to make to fit a 14/2 or 12/2 wire in? 3/4" or less??!!
 
MHElectric said:
A small notch on the bottom of the joist large enough for a wire to get tucked in is not going to make the house fall over! How big of a notch do you need to make to fit a 14/2 or 12/2 wire in? 3/4" or less??!!
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Many cases no. Still the top and bottom chord area is critical. If it were a truss or engineered framing member maybe even more critical.

If your joist is a minimal span you can get away with a lot. If it is spanning near it's designed max span - it don't need any help at making the floor above any "bouncier" then it already may be.
 
From the IBC 2308.8.2 Notches in the top or bottom of joists shall not exceed one-sixth the depth and shall not be located in the middle third of the span.
So if you can stay out of the middle third you should be OK.
 
RICK NAPIER said:
From the IBC 2308.8.2 Notches in the top or bottom of joists shall not exceed one-sixth the depth and shall not be located in the middle third of the span.
So if you can stay out of the middle third you should be OK.
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That likely only applies to natural lumber type framing members, engineered members may have their own instructions.
 
Depending on the size of the room could be easier to fur the ceiling down with 3/4" plywood strips on the bottom of the joist -- than to notch 3/4" - still sounds like the finish is not a major concern with exposed wires & may not have to be protected in the first place.. I never liked a shoddy look to finish work
 
luckylerado said:
How does notching make this compliant? I would agree that notch and nail plate works if drywall is being installed but not for exposed work in a basement.
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Kind of see your point, but at same time cables are no longer on the under side of the joist.

Finished appearance wise - not worth the effort IMO they won't look any better.
 
Not sure if this applies in your area, but here(iowa) it is common for inspectors to require conduit for anything below the floor joists, and some really frown on any nm even drilled through joists. My two cents... Good luck :)
 
luckylerado said:
How does notching make this compliant? I would agree that notch and nail plate works if drywall is being installed but not for exposed work in a basement.
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Even notching does not solve the bigger risk: which is people hanging things from the wires. And as other's noted, a notch on the bottom side of a load carrying horizontal joist is the absolute worst place to have a notch. A hole weakens the joist a lot less.
 
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