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balloon framing, visible wall insulation from basement & crawl space -cover it?

balloon framing, visible wall insulation from basement & crawl space -cover it?


  #1  
Old 10-19-14, 07:48 AM
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Question balloon framing, visible wall insulation from basement & crawl space -cover it?

Hi All

We recently purchased a house, which was built in 1950s and has balloon framing. From the unfinished basement and good hight crawl space, I can see the wall insulation of the first floor walls (i.e. the insulation/framing gap is visible in the rim joist area). it's not falling out in crawl space / basement, but it looks creepy. I want to 'cover it'.

This is what I am planing to do. Is it safe from fire / mold / ventilation / squeaking perspective?

From the bottom / (basement / crawl space), push some more fiberglass insulation up in the wall - a couple of inches or anything that I can push 'up' in the gap. Then cover the gap with 1/8 inch plywood (or lauan) by cutting pieces which can fit between the joists - about 5-6 inch by 16 inch. glue & crew them under the sub floor. Then run a bead of some (which?) caulk to cover any gap that still remains between the wall and this plywood, which will be screwed to the subfloor.

Thanks for any advice / recommendations / heads-ups before I undertake this big project

Thanks
danis
 
  #2  
Old 10-19-14, 08:07 AM
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Those was should have been fire blocked before insulation.
Those walls are open all the way from the basement to the attic and make great chimneys in a fire.
Need to be using 2X lumber for the blocking not 1/4".
 
  #3  
Old 10-19-14, 08:13 AM
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Hi danis,
When you add insulation, don't push too hard, just fill neatly.

Covering that stud bay will require a fire rated material. Sheetrock or cement board are two, but some thickness (greater than 1/8" plywood) may meet your local codes. Sheet metal would also work. Others here may know what is acceptable in NJ. Then the caulking needs to be a fire rated caulk.

Now the hard part. If those channels are open to the attic, the same or similar approach is needed both for fire control and heat loss.

While you are working in the basement, go ahead and seal the rim joist to foundation, a notorious source of air leakage. Insulation would be good as well.

Bud

You are too fast for me Joe
 

Last edited by Bud9051; 10-19-14 at 08:14 AM. Reason: addition
  #4  
Old 10-19-14, 09:30 AM
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Thank you VERY much Jim and Bud. I am glad I asked this before I proceeded with the project . I would have done it wrong.
If this affects fire - i would go with proper permit and let the town inspect it.

Three follow-up questions:
1. When you say "they make great chimneys in a fire" - does that mean you are recommending against doing it? I would follow Bud's suggestion of also doing rim joist insulation, so it would cover everything up in the basement. Do I loose a 'feature' of this 'chimney'? I may not be able to close it on the attic end as suggested by Bud, because the attic is very small already - even in the center - so it will be very difficult / almost impossible to reach to the end / side to cover it up.

2. We got two different recommendations on 2X lumber v/s fire rated drywall. So, can I use fire rated 5/8 drywall? It will be easier to cut / work with .

3. In some places, the subfloor plywood goes all the war to the side and I don't see that falling insulation(for example, under the kitchen). If I undertake this project and get the inspector in, will he require that this new fire rated stuff is applied everywhere, i.e. will i be making it a 'bigger project then it needs to be', or is it okay to just cover the areas which are open and look creepy.

thanks
 
  #5  
Old 10-19-14, 10:26 AM
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I don't know that a permit and related inspections are required for insulation improvements. Calling your local code office would be the correct approach.

Following code required fire blocks is a good practice and could well be required here, again call.

The chimney effect is "BAD", thus these vertical cavities need to be blocked. Normal construction would place a 2x4 across the cavity, but 5/8" fire rated drywall should be acceptable, again call.

I can't answer regarding the current flooring blocking access and maybe acting as a fire block.

In addition to the insulation benefits, blocking the air leakage up through those cavities will further reduce your heat loss. Calling the local code office might entail some extra work, but doing so will ensure the job is done right. A fire can spread extremely fast through a house with balloon walls, not your interior walls may be open as well.

Bud
 
  #6  
Old 10-19-14, 12:42 PM
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Thanks again Bud. Since Chimney effect is bad, it's for sure now that I need to do something .

I found a stone/rock wool insulation product - 7.25 inch deep batt. It's rated for R30 and is fire resistant upto 2150 F. If I cut it in size that would fit within the rim joist area, would that cover both purposes of adding a fireblock and adding insulation? Or do I really need to add that 2x4 piece of lumber?
 
  #7  
Old 10-19-14, 01:54 PM
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From what I know, a physical block is required, not just the dense insulation, although that would be good for the rim insulation. Do some caulking before the insulation is added. I'll add a couple of great links with some related info and a bunch on just renovating and air sealing.

http://www.efficiencyvermont.com/ste...ide_062507.pdf

http://www.buildingscience.com/docum...build-renovate

Bud
 
 

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