Attic acess clearence?

[Guest]

Re: Attic acess clearence?

Tonyi said:

<big snip>The existing joists were old rough cut 2x12 and plenty sturdy...until the guys who did the foundation extension (50-70 years ago) notched'em at the ends to where they were only about a hands width wide sitting on top of a brick wall built between the old and new sections. <snip>

Were those by any chance "Fireman's" notches in those floor joists? If so, it's a feature by design to keep the firemen safer.

[ September 29, 2003, 10:35 PM: Message edited by: awwt ]

 

[tonyi]

Re: Attic acess clearence?

Originally posted by awwt:
Were those by any chance "Fireman's" notches in those floor joists? If so, it's a feature by design to keep the firemen safer.

No these clearly happened as a result of the ~70 year old mods in that area of the place. The rest of the building had nothing similar where the framing and foundation were in "stock" condition. That addition (one of several) was just an incompetently done hack job. The floor in the new area had 12' spans framed with 2x6's spaced about 3' apart. This is in a relatively rural town in upstate NY that didn't even have a building inspection department until 1986. You find all sorts of "creative solutions" (both structural and electrical) in older places in the area. The farmers had their own way of doing things back then . ex. One place had an old upside down buried car body being used as a septic tank...

 

[iwire]

Re: Attic acess clearence?

Originally posted by awwt:
Were those by any chance "Fireman's" notches in those floor joists? If so, it's a feature by design to keep the firemen safer.

Wayne I have never heard that term in this area, what are they and how do they help firemen?

[ September 30, 2003, 03:27 AM: Message edited by: iwire ]

 

[Guest]

Re: Attic acess clearence?

Forgive me, it's going to be hard to paint an emotional word picture here. In older brick buildings (think Boston) the floor or ceiling joists go into pockets in the brick. The ends of the joists are specially notched to allow "graceful" collapse of the floor/ceiling. This helps prevent the collapse of the floor in a manner that would trap or flatten the firefighters as they fight the fire or while they break open or ventilate the walls, floors, &/or ceiling. Maybe an oldtimer, renovator, or firefighter can jump in here to fill in my gaps or to provide a photo or drawing.

 

[iwire]

Re: Attic acess clearence?

I understand now Wayne, while I do not remember hearing that term, something is rattling around in the back of my head about this.

I think I have heard of this before, thanks Wayne.

If I remember it had to do with letting the floor go without taking the brick walls with it. Limited collapse instead of total collapse.

[ September 30, 2003, 06:29 PM: Message edited by: iwire ]

 

[drg]

Re: Attic acess clearence?

Rob,
We are informed not to drill into laminated beams, and truss work but we have always drilled thru TJI's because of the alignment problem of the knockouts.
Is there more to consider when boring thru these TJI's with a 2" (hole hog) bore bit ????
As a note the 2" hole is always spaced on center of the TJI just like we would bore any floor joist.

 

[ryan_618]

Re: Attic acess clearence?

It is truly amazing what you can do to a TJI/BCI joist. Try to stay in the middle 1/3 of the span when drilling these. You can actually drill up to an 8" right through the center of these and not have any problem!

Now, when you talked about drilling dimensional lumber you stated that you drill in the center. I hope you are refering to the center of the board, meaured vertically, not the center of the span, measured horizontaly. With dimensional lumber you want to drill towards the end.

 

[drg]

Re: Attic acess clearence?

Yes you are correct Ryan.
When boring the length of the basement thru the floor joist's we are usually within 2' from the sill plate and we use a chalk line end to end for alignment, along with a speed square that is marked for vertical centering of the hole in the joist.

 

[ryan_618]

Re: Attic acess clearence?

With only a two inch hole you should be fine, but is two feet from the sill plate the middle of the span? That would only be a 3 foot long joist!

You shouldn't have anything to worry about, but if you drill bigger than two inch you'll want to be farther away from the sill than that. Hope this helps,

 

[drg]

Re: Attic acess clearence?

Come to think of it we do use a 2 9/16 " bore bit also. How far from the sill plate should these holes be placed centered on the joists ???

Thanks

 

[ryan_618]

Re: Attic acess clearence?

You'll want to stay inside the middle 1/3 of the joist span. For example: If your joist spans 20 feet you will want to be in the area between
10'-15'

Please note that is the exact opposite of dimensional lumber. With 2 X material (2x6, 2x8, 2x10, etc.) you must STAY OUT of the middle 1/3 of the span and also out of the bottom two inches of the board.

Hope this helps,

[ September 30, 2003, 09:30 PM: Message edited by: ryan_618 ]

 

[Guest]

Re: Attic acess clearence?

Back to knotholes and 1" drilled holes in truss chords: I am fairly confident that if you talk to your truss person up front they would be happy to stamp your truss plans approved for up to 1" holes if you keep them in the middle of the chord. I know the bottom chord is in tension, but if the holes were too close to the edge they would structurally be more like a notch. Maybe 1" is pushing it, but 3/4" holes should be OK if you run it by the truss company up front and have them stamp the plans. They might want to do a field inspection to make sure you didn't drill outside of that, or they might trust the local inspector to enforce the exception. You might have to pay an extra $100 for the stamp too. My point is that anything is possible if you talk about it upfront. For instance, normally you cannot cut a stairway perpendicular to an attic truss, but again if it's mentioned up front the truss engineer can design a workaround and put his/her stamp on it. Better policy to run stairs parallel, but sometimes it's not in the aesthetic design limitations.

PS: My spelling has gotten a lot better by using ieSpell -- not just because it catches the mis-spelled words, but it slowly teaches me the right way to spell them-- less and less errors every time I use it. Now I just need to find ieGrammar

ieSpell still lets the synonyms slide by, or any wrong word choice.

The forum spell check is a good feature for those that do not have IE, but I find it slower and more cumbersome than ieSpell. If Mike Holt added a grammar checker, I'd be the first to jump on board!

I guess the other option would have been to go to school

 

[macmikeman]

Re: Attic acess clearence?

I think the last several replies to my drilling the truss is full of beans and I am going to tell you why. Generally an access hole to an attic is located in the hallway. You have a bearing wall on either side of the hallway. The usual standard found on the majority of residential is a 40" wide hallway. The truss in most cases are perpendicular to the hallway . I drill a 1/2" hole when I am within 6 foot of a scuttle hole and I run across the top of the lower portion of the rafters thru attics when NOT within 6 feet of said scuttle holes. Sometimes I use running boards. I started wiring houses in 1976 and have not caused a single one yet to fall down. The rafters are quite fine from my seldomly drilled puka (hole in Hawaiian). There are quite a few of the responders to posts on this site who I am not sure if they actually know anything about what they are actually posting about.

 

[iwire]

Re: Attic acess clearence?

Originally posted by macmikeman:
I think the last several replies to my drilling the truss is full of beans and I am going to tell you why. Generally an access hole to an attic is located in the hallway. You have a bearing wall on either side of the hallway.

Walls under the truss you are drilling do not make a difference.

The fact that you think it does make a difference tells me you do not understand how a truss works.

The bottom chord of a truss keeps the ends of the truss from spreading, much like collar ties in a conventional roof system.

This can be a very important feature for those of us in the snow belt, add 6", 12", 20" of snow on your roof and you do not want any weak spots.

Something for someone in your location does not have to worry about I think.

Originally posted by macmikeman:
I started wiring houses in 1976 and have not caused a single one yet to fall down.

It is important to remember that just because you have always done something that way does not make it correct.

I do not think that any of us think drilling a few holes would cause a collapse, but the fact is these are engineered products and in many areas of the country building inspectors will not allow any modifications (including holes for wires) without documentation from an engineer or the truss manufacturer.

Originally posted by macmikeman:
The rafters are quite fine from my seldomly drilled puka (hole in Hawaiian).

You do understand there is a large difference between rafters and trusses right?

Originally posted by macmikeman:
There are quite a few of the responders to posts on this site who I am not sure if they actually know anything about what they are actually posting about.

Well that is interesting, as at least a few of these guys responding to your post on drilling holes in trusses are inspectors and have attended training is building codes.

As for my self, I am not an inspector but I have worked on enough jobs to know that you never drill engineered lumber products with out express permission.

Now, it is 38F here this morning how do I get a job in Hawaii?

[ October 03, 2003, 05:52 AM: Message edited by: iwire ]

 

[drg]

Re: Attic acess clearence?

We had a guy who drilled into the side of a 69kv transformer last year. not once but twice,
he is not employed with our company anymore.

John