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Discussion Starter · #1 ·
Hi
yeah I'm new here.
I've run into a situation and I'm hoping some one can help .
I'm in the planning stage of doing my first basement finish job under my own business .
I'm planning on leaving the insulation wrap installed by the manufacturer and holding the floating wall off the foundation by 5.5".
my Question is can I use a 2x6 top plate (instead of 2x4) where the joist meets the foundation as a dual purpose fire block/top plate combination?

Thanks in advance.
 

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I've done this and it was signed off.
Welcome to ContractorTalk. Stop by the Intro forum and give us a note to introduce yourself.

I've also done it. The top plate should be p.t. if it touches concrete.

I'm probably just having a brain fart, but what does "leaving the insulation wrap installed by the manufacturer" mean?
 

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Discussion Starter · #4 ·
the basement is wrapped in a vapor barrier insulation.
looks like this , (pic borrowed from another thread)
Home owner doesn't wan't me to spend the time to take it down. just build the new walls in front of it.
 

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Probably anywhere that sells insulation. It might cost a little more but it's handy to have when framing, I've used it a lot to fill in those awkward cavities. It gives you insulation value too instead of using a wood plate which is nothing but a heat conductor.
 

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General Contractor
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If your new wall will be 5.5" away from the foundation I don't see how 2x6 top plate can be used as a fire block. You need fire-blocking go from the sill plate to the top plate of your new wall.
We put 1/2 sheetrock from the sill plate to the outer edge of the new constructed wall and build out walls... Simple and quick.
In addition you should check with your building department if you need vertical fire-blocking done 10' OC. That is new code requirement and last few basements we did, we had to install it.
 

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We always have to draft stop every 10' horizontally, and it has to be fire caulked to the concrete if over an 1/8" gap. The insulation could not be between the draft stop and the concrete.
Also, rockwool has limited acceptance here, mainly around hard to reach penetrations.
If the whole cavity at the top of the wall is filled with rockwool, most munis will fail it, and those that don't will require some sort of support. (IOW, you can't just stuff the cavity full.)
 

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Discussion Starter · #11 ·
Yeah, it's looking like the "Wrap" is going to have to come down.
Frame to the foundation, cover all the fire block issues, and insulate, minimum R-19 required on all exterior walls by city of Broomfield.
This is going to be a Great learning experience to say the least.
I mean this isn't my 1st Basement , but its the first one I've done in the last 15 years and as the one responsible for the WTF's.
 

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AbsoluteBasements said:
We always have to draft stop every 10' horizontally, and it has to be fire caulked to the concrete if over an 1/8" gap. The insulation could not be between the draft stop and the concrete. Also, rockwool has limited acceptance here, mainly around hard to reach penetrations. If the whole cavity at the top of the wall is filled with rockwool, most munis will fail it, and those that don't will require some sort of support. (IOW, you can't just stuff the cavity full.)
that's strange, most inspectors around here like seeing the Rockwool.
 

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I just read things here again, and agree with Greg24k why 5 1/2" away from the wall? that looses lots of area? Around here rockwool is good for most places. Not the best to work with! LOL Even the PITA local inspector likes it!
 

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I'm thinking he means the FACE of the wall with be 5 1/2"...not 5 1/2" of dead space behind.

I start squaring basement finishes with 4 1/2" to the face, but often times have to move out if the concrete wall isn't plumb, or the foundation isn't square.
Worst one we did had the new wall 3 1/2" out of parallel to the concrete to keep the room square. Same thickness as a 2x4, I think someone nailed a 2x4 to the footing on the wrong side of the mark, during foundation layout or something...
 

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Discussion Starter · #16 ·
yes, 5 1/2" to the face , so as not to crush the insulation against the foundation. But everything is looking like that stuff is coming off anyway because of the Vertical fire blocking that is required every 10' along the distance of the walls and @ all intersections. And the R-19 minimum on all exterior walls , which this project is 75% exterior walls.

Thanks Everyone for your comments and advice. I think i'm going to like it here. ;)
 

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Joseph A. Capece
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IRC 2009

“R302.11.1.1 Batts or blankets of mineral or glass fiber. Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be permitted for compliance with the 10-foot (3048 mm) horizontal fireblocking in walls constructed using parallel rows of studs or staggered studs.”
 
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