Blown in Insulation

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squaredan

Senior Member
Location
Pennsylvania
HI,

I was wondering if anyone has encountered Blown in Insulation(Spray foam type) while trying to fish in outside walls?? I have never came across that problem but wanted to know if anyone has and if there is any tricks or is it just one of those walk away jobs, just cannot be done... Dan
 
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insulation

insulation

i have had to fish walls with spary foam and it can be done. a pain. you have to fish betwwen the foam and the sheet rock then do some carving usualy with a jab saw to get your cut in box to fit very snug.
 

inspector 102

Senior Member
Location
Northern Indiana
If these are Structural Insulated Panels (SIP) that are full depth foam, I believe there is a horizontal chase in each panel to pull wiring through. Otherwise you have to router a groove into the panel to chase the wiring. I also believe there are limits on how much you can remove from the OSB skin on these panels and still keep the structural integrity. Have seen a couple homes built with these panels and it looks like more work than it is worth. I understand the energy savings, but where is the tradeoff for all the additional issues? Just my thoughts.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
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EC - retired
Some of the older foam insulation blown in back in the 70s was pure cr___ and is easy to fish, other than it crumbles into powder when touched. Wear a mask and take a vacum.

I had some sprayed between the studs in my basement a couple years ago. Fishing should work but stay midway between the studs with boxes. New stuff will not move or break easily.
 

ActionDave

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Location
Durango, CO, 10 h 20 min from the winged horses.
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Licensed Electrician
There are two kinds of spray foam- open cell and closed cell. Fishing though open cell is slightly more difficult than fiberglass but doable with fish sticks.

Closed cell is hard and dense. I have never fished a wire through closed cell, but I believe one would have to drill through it with a remodel bit to get down the wall.
 

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
I would not want to fish thru closed cell foam either. As someone stated keep the hole between the sheetrock and the foam. Usually the foam is only 2" or so thus there should be a hollow area.
 

squaredan

Senior Member
Location
Pennsylvania
I believe he's talking about the expanding spray foam insulation. Like the blue stuff you see Mike Holmes use all the time.

Yes that is were I saw it.. I always knew about that type but never thought about how it would be to fish down walls with that Spayed unit now... thanks for all the comments

Dan
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
Yes that is were I saw it.. I always knew about that type but never thought about how it would be to fish down walls with that Spayed unit now... thanks for all the comments

Dan

Like the saying says "while I don't have a soulution, I can certainly admire your problem.";)
 

220/221

Senior Member
Location
AZ
Some of the older foam insulation blown in back in the 70s was pure cr___ and is easy to fish, other than it crumbles into powder when touched. Wear a mask and take a vacum.

.

I came across some of that for the first time a couple weeks ago. There was a full 24" gap at the top of all the walls where the foam had broken down and settled. The attic area was full of it too. I imagine all the guys working on the project will die a little sooner. The fine powder was nasty!
 

hurk27

Senior Member
I have done it, but it is a pain unless your on a gable end wall, most flex bits wont flex enough to go down at the roof edge, I was lucky as the one I had to do had a basement, and drilled up to the attic, to get across the house to the part that was on a slab, for the most part, once I drilled through the top plates, I could push the flex bit down till it stopped, then just hit the trigger to get it to move the rest of the way, this kept me from punching through the outside wall, also use the metal detector feature on a good stud finder to locate you bit, or a tracer unit then cut the box in close to it.
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Good luck with it.:roll:
 
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