Placing decking in attic

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I may be using the wrong term(s) so let me describe the house.

i know your not that dumb, but i have to do it this way so i can get it right.

the house is on an incline and there is 3 - 7 ft of crawlspace.
the floor is 2 x 8 construction maybe 2 x 10 or 2 x 12, i didn't look that close.
the walls are 2 x 4 construction.
the ceiling (joists) or what ever they are called are 2 x 6 construction.
they are also 2 x 12 construction over the living room and kitchen area - nothing will be placed there.
the rafters were nailed to the ceiling joists, there are no trusses.
the entire attic is open except for 3 or 4 supports used to hold up the center post of the roof and the corners while
the other rafters were nailed in place.


i hope this helps,
james
 
Isn't the diagram Dennis posted for the strength of the framing members, and has nothing to do with the placement of holes from an electricians perspective?

Is a hole drilled 5/8" from the edge of a framing member compliant for the NEC ? Wouldn't seem to me that it would be.

Similarly, I don't think that furring strips are useful for protecting the romex from floor decking screws.... they aren't thick enough - 3/4"
 
A/A Fuel GTX said:
Disagree........How can you have ceiling joists in an area that has an attic? That sure sounds like a truss to me.
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2X6 bottom cord? That is a hefty truss!

realolman said:
Isn't the diagram Dennis posted for the strength of the framing members, and has nothing to do with the placement of holes from an electricians perspective?

Is a hole drilled 5/8" from the edge of a framing member compliant for the NEC ? Wouldn't seem to me that it would be.

Similarly, I don't think that furring strips are useful for protecting the romex from floor decking screws.... they aren't thick enough - 3/4"
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It has everything to do with EVERYONE. Had a buddy call me and said "MIKE my guys drilled the holes an 1 1/4" fome the bottom of the floor joists (the entire length of the basement) and the building inspector failed the structure inspection". I said "yes". They had to pull all home runs and sister all the joistsd in the basement!!!!!


The NEC is under the building code NOT the other way around!
 
jxofaltrds said:
disagree. OP said joists so trusses are not what is being discussed.
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james_mcquade said:
I may be using the wrong term(s) so let me describe the house.

i know your not that dumb, but i have to do it this way so i can get it right.

the house is on an incline and there is 3 - 7 ft of crawlspace.
the floor is 2 x 8 construction maybe 2 x 10 or 2 x 12, i didn't look that close.
the walls are 2 x 4 construction.
the ceiling (joists) or what ever they are called are 2 x 6 construction.
they are also 2 x 12 construction over the living room and kitchen area - nothing will be placed there.
the rafters were nailed to the ceiling joists, there are no trusses.
the entire attic is open except for 3 or 4 supports used to hold up the center post of the roof and the corners while
the other rafters were nailed in place.


i hope this helps,
james
Click to expand...

These "joists" are no different than the "joists" for the flooring system, and the builders actually cut "rafters" on site.
There is not a lot of that done anymore and is becoming more carpenters that don't even know how to build such a roof. Using engineered truss systems is generally less expensive, uses less lumber and is overall lighter weight. They can build pretty complex roof/ceiling systems too, all the installer needs to do is read the plan and put them up in the right sequence.
 
jxofaltrds said:
2X6 bottom cord? That is a hefty truss!



It has everything to do with EVERYONE. Had a buddy call me and said "MIKE my guys drilled the holes an 1 1/4" fome the bottom of the floor joists (the entire length of the basement) and the building inspector failed the structure inspection". I said "yes". They had to pull all home runs and sister all the joistsd in the basement!!!!!


The NEC is under the building code NOT the other way around!
Click to expand...

Geez... are you telling me it is ok to drill holes for NM 5/8" from the edge of a wall stud? That , and that a furring strip is not thick enough for the proposed application was my point... not which code supercedes which code.
 
realolman said:
Geez... are you telling me it is ok to drill holes for NM 5/8" from the edge of a wall stud? That , and that a furring strip is not thick enough for the proposed application was my point... not which code supercedes which code.
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Relax.

Yes you can.

Furring strip is big enough. I could use 'shims' if I wanted.
 
What's 300.4 (A)1 all about?

the edge of the hole is not less than 1-1/4" from the nearest edge of the wood member

and it seems to me that the 3/4" furring strip is going to put the top of the NM approx 9/16" from the decking right on the top of the joist ... right where you 're going to be putting the screws. Doesn't 300.4(D ) require 1-1/4" "where nails or screws are likely to penetrate."

the shims I don't get at all.
 
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renosteinke said:
Dennis, I think your reply is pointing the OP in the wrong direction.

First off, the graffic is for certain framing members made of dimensional lumber. Glulams and TJI's have different rules for hole making.

Second, the atrwork does not include 'engineered trusses.'

By far the most common form of roof framing, these trusses are designed with the absolute minimum amount of wood. Even simply placing decking in your attic and storing stuff can be a risky proposition; many have found this out the hard way when they attached hoists to their garage trusses.

Such trusses are not allowed to be drilled or notched at all.
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Well I stated in my first point that I didn't think you could drill a truss. I thought it was clear that this is for regular framing members and I posted it after others were asking about it.

Point is we still don't know if they are trusses but I am assuming so --- this graphic does not include trusses or engineered joist. It is for standard joists
 
realolman said:
What's 300.4 (A)1 all about?

the edge of the hole is not less than 1-1/4" from the nearest edge of the wood member

and it seems to me that the 3/4" furring strip is going to put the top of the NM approx 9/16" from the decking right on the top of the joist ... right where you 're going to be putting the screws. Doesn't 300.4(D ) require 1-1/4" "where nails or screws are likely to penetrate."

the shims I don't get at all.
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what if your hole is closer than 1 1/4"? what do you do?

you do not put decking screws in the 'field' of the decking do you?

I think every nail or screw could penetrate. likely? more and more likely with todays construction workers!
 
realolman said:
Geez... are you telling me it is ok to drill holes for NM 5/8" from the edge of a wall stud? That , and that a furring strip is not thick enough for the proposed application was my point... not which code supercedes which code.
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The point of using firring strips is not to keep screws from penetrating the wires, but to keep the boards/flooring/decking off the wires. Doesn't matter how thick the firring strips are. That's why you're supposed to keep wires 1-1/4" from firring strips. In case of farsighted installers!
 
what if your hole is closer than 1 1/4"? what do you do?
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you don't use them for NM...


The point of using firring strips is not to keep screws from penetrating the wires, but to keep the boards/flooring/decking off the wires. Doesn't matter how thick the firring strips are. That's why you're supposed to keep wires 1-1/4" from firring strips. In case of farsighted installers!
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It seems to me that the point of 300.4(A) 1 and 300.4(D ) is to keep screws from penetrating the wires. If that's not the reason, then what is the reason for them?


I don't think the OP posted to see how he could put decking over the wires... any boob could figure that out... I think he posted to see how he could do it and be code compliant.. How about explaining to this old dunce why complying with 300.4 (A)1 and 300.4(D) "doesn't matter"
 
realolman said:
you don't use them for NM...






It seems to me that the point of 300.4(A) 1 and 300.4(D ) is to keep screws from penetrating the wires. If that's not the reason, then what is the reason for them?


I don't think the OP posted to see how he could put decking over the wires... any boob could figure that out... I think he posted to see how he could do it and be code compliant.. How about explaining to this old dunce why complying with 300.4 (A)1 and 300.4(D) "doesn't matter"
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I never said not to comply with 300.4(A)(1) or 300.4(D) or that it "didn't matter".
I said it didn't matter how thick a furring strip was as the furring strip is used only for spacing. I did say that you had to keep the wires 1-1/4" from the edge of furring strips for "farsighted" installers. Meaning if someone was putting a board(s) on the furring strips there is less of a chance they would hit the wires if they missed the furring strips.
But the "thickness" of the furring strips has no bearing on the requirement, nor is it mentioned in 300.4(D)

Is that explained well enough?
 
realolman said:
you don't use them for NM...






It seems to me that the point of 300.4(A) 1 and 300.4(D ) is to keep screws from penetrating the wires. If that's not the reason, then what is the reason for them?


I don't think the OP posted to see how he could put decking over the wires... any boob could figure that out... I think he posted to see how he could do it and be code compliant.. How about explaining to this old dunce why complying with 300.4 (A)1 and 300.4(D) "doesn't matter"
Click to expand...


Read 300.4(A) again, what it is telling you is that if you stay 1 and 1/4 inches from the edge of the stud there is no need for additional protection but "Where this distance can not be maintained, the cable or raceway shall be protected from penetration by screws or nails by a steel plate(s) or bushings 1/16th" thick.


What you have is ceiling joists and if you look at Dennis"s pic that was posted and my code reference you will see where you can and can not notch the joists.
 
Now daggone it, just hold on here a minute. Of course you can use holes that are close to the surface if you put plates on them.
I never said not to comply with 300.4(A)(1) or 300.4(D) or that it "didn't matter".
I said it didn't matter how thick a furring strip was as the furring strip is used only for spacing. I did say that you had to keep the wires 1-1/4" from the edge of furring strips for "farsighted" installers. Meaning if someone was putting a board(s) on the furring strips there is less of a chance they would hit the wires if they missed the furring strips.
But the "thickness" of the furring strips has no bearing on the requirement, nor is it mentioned in 300.4(D)

Is that explained well enough?
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No as a matter of fact it is not. but go with it. I give up.
 
so you are saying that if the cables were installed parallel to the joist, it would have to be 1-1/4" below the top edge of the joist, but if it is perpendicular to the joist and parallel to a furring strip it can be right under the decking and right on top of the joist, but must be 1-1/4" away horizontally from the furring strip?

It appears I did not understand that correctly. Thank you for the education
 
jxofaltrds said:
Could you come to Ohio and show us how you wire a home and need no p-plates?

Possible? Yes. Real world? Rare.
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I used to do it all the time - easy in 2x6 walls but a bit harder in 2x4. It also depends on how complicated the framing is. A basic rectangular home with crawl and trusses is very easy to wire without nail plates.
 
Dennis Alwon said:
I used to do it all the time - easy in 2x6 walls but a bit harder in 2x4. It also depends on how complicated the framing is. A basic rectangular home with crawl and trusses is very easy to wire without nail plates.
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Agreed. The hard place is in outside corners should you choose to run your wire that way.
 
realolman said:
so you are saying that if the cables were installed parallel to the joist, it would have to be 1-1/4" below the top edge of the joist, but if it is perpendicular to the joist and parallel to a furring strip it can be right under the decking and right on top of the joist, but must be 1-1/4" away horizontally from the furring strip?

It appears I did not understand that correctly. Thank you for the education
Click to expand...

Yes. Maybe we thought you knew what we were saying. Glad you understood us before we understood you!
 
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