# new I Joist Question



## icerock drywall (Aug 16, 2012)

went to a job the other day and the contractor put new I joist in the ceiling ...the he cut some up 24'' and put them on the top and the bottom...my Question is do they need to be there and if so how do you get air flow, the insulate bats hit the I joist


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## griz (Nov 26, 2009)

Don't get the question.

Got a pic?


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## icerock drywall (Aug 16, 2012)

get some monday


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## Golden view (Feb 16, 2012)

You talking about bird blocking? Lateral bracing? 22" blocks if the CJs are spaced 24" OC and have a 2" flange?


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## icerock drywall (Aug 16, 2012)

Golden view said:


> You talking about bird blocking? Lateral bracing? 22" blocks if the CJs are spaced 24" OC and have a 2" flange?


he said it was to keep the I joist from twist... I looked up I joist from twisting and I I could find was steel braces. but he made is out of the I joist and it will be very hard to insulate the way he did it. He also told the home owner the place where he got the beam told him thats the way you do it. but on the internet I cant find anyone who did it this way.
Also he just put the I joist on top of the beam. said it is stronger his way?


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## muskoka guy (Nov 16, 2013)

If you have engineered lumber in the roof, there must be something that came with the roof package showing the engineering. I am sure the building inspector will want to see it.


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## Tinstaafl (Jan 6, 2008)

Is it similar to the blocking shown here?


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## icerock drywall (Aug 16, 2012)

Tinstaafl said:


> Is it similar to the blocking shown here?


the blocking is about 16'' in the room from that one and one more at the top


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## Tinstaafl (Jan 6, 2008)

Not sure what's going on with an extra piece at the top, but such blocking is typical to resist twisting. You just cut your batts to fit.

You mention air flow. Are these cathedral ceiling rafters rather than horizontal ceiling joists? I can't think of any other reason you'd _want_ air flow.


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## icerock drywall (Aug 16, 2012)

Tinstaafl said:


> Not sure what's going on with an extra piece at the top, but such blocking is typical to resist twisting. You just cut your batts to fit.
> 
> You mention air flow. Are these cathedral ceiling rafters rather than horizontal ceiling joists? I can't think of any other reason you'd _want_ air flow.


cathedral ceiling and if you spray foam you dont need air flow ? 
the thing is its going to be hard to spray it with the lower blocking he did


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## Tinstaafl (Jan 6, 2008)

Yeah, generally foam eliminates the need for venting, though it costs significantly more to go that route.

I guess we'll just have to wait for pics to see exactly what the situation is.


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## icerock drywall (Aug 16, 2012)

here it is...


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## Golden view (Feb 16, 2012)

icerock drywall said:


> here it is


Pretty lousy place to locate those blocks. Some inspectors would even fail that. Generally it's at the exterior of the wall so insulation is continuous, plus the blocking can be nailed to the plate to stiffen things up more.


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## icerock drywall (Aug 16, 2012)

he said this is to spec....lol how do you insulate that?


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## icerock drywall (Aug 16, 2012)

the top


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## overanalyze (Dec 28, 2010)

That's a new way to me. Blocking like that is usually directly above all bearing points.


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## icerock drywall (Aug 16, 2012)

overanalyze said:


> That's a new way to me. Blocking like that is usually directly above all bearing points.


thanks for your help...I dont like what he did and the inspector said its good !


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## overanalyze (Dec 28, 2010)

icerock drywall said:


> thanks you your help...I dont like what he did and the inspector said its good !


Well...I guess then you have to foam it. We had a house we built a few years ago. Long story short, we ended up replacing the fiberglass with foam after excess moisture was found. Ventilation in a cathedral setup like this just introduces cold air where you don't want it.

What climate zone are you?


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## tjbnwi (Feb 24, 2009)

Squash blocks over bearing points is all I've ever done. I've never seen an I-joist twist once the sheathing is nailed off.

Tom


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## Tinstaafl (Jan 6, 2008)

icerock drywall said:


> I dont like what he did and the inspector said its good !


Well that might pass framing inspection... 

I can't see using fiberglass batts on that, though.

Some years back, a crew I was on built a huge cathedral ceiling insulated with batts. Somehow nobody supervised the grunts putting the baffles & batts up, and they started the baffles tight up against the fascia board.

Next hard winter, the HO had water literally pouring out of the light fixtures in the ceiling. Cutting the baffles back 6" to allow air flow cured that, and he hasn't had trouble since.


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