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Question about Roxul and Wiring

matt_i

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Mar 14, 2008
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SE Michigan
Question for those of you who have put in Roxul....I am planning on doing this for my sidewall insulation in a 25 x 40 shop. The topic didn't seem to purely fit electrical since its more of an insulation question.

However I'm wondering if it would be a worthy aid to cutting and fitting insulation to use a little extra vertical wire and run the wires horizontally above the top wall plate rather than horizontal drilling between stud cavities for the shortest route.

If using fiberglass I'd definitely do the shortest route wiring because its relatively easy to tear apart or massage the insulation around the wire (have done this in the past many times). From what I read about Roxul its very rigid and would seem to add another (or a longer) fitting step having to work around horizontal wiring.

Just curious what others think based on their experience with the product. I've never actually had it in my hands to make my own judgement. Thanks for any input!
 
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walrus

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Nov 12, 2008
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Roxul can be cut just like fiberglass. Not sure you can rip it apart like fiber though
 

Angelfire

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Mar 22, 2012
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New Mexico and Ireland
I did Roxul in my addition on my home and am planning to use it on my detached hopefully soon. I'm currently in the process of wiring up the shop and gave it no thought at all whether to run the wires horizontally. With the mineral wool, I just held the batt up against the cavity, marked where the wires ran (with a knife), then made a slit across the batt. Slip the batt behind the wire and when in place the batt closes over the wire. You can't tell where the wires or slits are if it's done properly and it's easy. So my recommendation is to save on the cost of wire and get a cheapy bread knife from the dollar store (or two depending on how much insulating you have....they do wear out!).
Cheers.
 

rlitman

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Oct 18, 2010
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Long Island
You can use a knife, and you can even snap the insulation. If you bend it and pull a little, you can break it apart into a piece for above and below the wire, and then push it back together. It's actually easier to mess with than glass.
 

Rigpig

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Feb 13, 2010
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Victoria,BC
I did my whole shop with Roxul and as mentioned above, just install the lower section of a bat keeping it off the wall a few inches so you can see where the wires run and cut a slit into the bat then push it in over the conductors. Get an old serrated bread knife, works great.
 
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Jim_No_Garage

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Jan 15, 2011
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Millington NJ
Somewhere entombed in a family room wall is a Farberware Steak knife I was using as described above to cut and fit roxul into the interior partition walls.

I didn't miss it until after the sheet rockers had come and gone. Doh!

Jim
 

DC73

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Dec 27, 2014
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Lubbock TX
I put Roxul in my shop.

I first picked up one of these serrated insulation knives: http://www.homedepot.com/p/Grip-Rite-Stone-Wool-Insulation-Knife-GRKNIFE/205449924

I pressed the Roxel batt into the wall cavity against the wire which produced a light imprint on the batt. I then used the knife to saw 1/2 way through the batt along the imprint (backside of the batt). Spread the batt apart at the cut and pressed it into place in the wall cavity while hiding the wire inside the slit. Wasn't bad at all.

DC
 

rharman

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Apr 22, 2012
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SoCal
I used a Ginsu knife when I put Roxul in my garage attic.

Got a couple of them free probably 20+ years ago at a home show. Dang things come in handy for stuff.
 
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Crazyjake8493

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Sep 26, 2014
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Upstate NY
Roxul is a lot easier to install and cut/form than fiberglass. I used Roxul in my garage with wiring for receptacles ran horizontally through the studs. I used an old serrated bread knife but they sell knives specifically for mineral wool as previously mentioned.

I would never use fiberglass again unless it was for ceilings or if money was a factor. Even then, Roxul isn't much more.
 
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