Where to buy Roxul

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markpelly

New Member
Jan 17, 2024
7
US
I am making a block off plate like many others in this forum but I cannot seem to find any retailers online or local that sell Rockwool Roxul. Am I just completely blind?

All of the listings I can find are just the standard batts for wall insulation. Does someone have a link for me to send me down the right path?
 
I am making a block off plate like many others in this forum but I cannot seem to find any retailers online or local that sell Rockwool Roxul. Am I just completely blind?

All of the listings I can find are just the standard batts for wall insulation. Does someone have a link for me to send me down the right path?
Rockwool is just Batts for wall insulation
 
though much wall insulation is fiberglass, and you need to have rockwool.
My orange box store has it, though.
 
Great to hear they have regular Rockwool, however is that normal wall batt safe for a block off plate and around the liner?
 
Great to hear they have regular Rockwool, however is that normal wall batt safe for a block off plate and around the liner?
Rockwool is fireproof, it is actually made from rock so nothing is flamable in it, there is Ytube videos showing it will not burn in walls with a torch to it, better than fiberglass or anything else. It is becoming the prefered insulation choice due to that.
 
Great to hear they have regular Rockwool, however is that normal wall batt safe for a block off plate and around the liner?
Yes but for the best performance you also want sheetmetal under it
 
Great to hear they have regular Rockwool, however is that normal wall batt safe for a block off plate and around the liner?
My point is that "that normal wall batt" is more often glass fiber than rockwool.
So make sure you buy the right thing. (And silicone caulk for any leaking edges around the metal plate.)
 
My point is that "that normal wall batt" is more often glass fiber than rockwool.
So make sure you buy the right thing. (And silicone caulk for any leaking edges around the metal plate.)
High Temp Silicone caulk. The HD sells it in large tubes specifically for this application.
 
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I stuffed a bunch of rock wool up there, then made a poor man's block off plate. Super HD aluminum foil.... easy to shape around pipe and bricks. After all, all you need to do is block air.
 
My point is that "that normal wall batt" is more often glass fiber than rockwool.
So make sure you buy the right thing. (And silicone caulk for any leaking edges around the metal plate.)
I understand the confusion, I was asking about the standard Rockwool wall batts and seeing if those were safe to use. I wasn't asking about standard fiberglass batts.
 
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Okay. That wasn't clear to me.

Yes, it should be okay (unfaced of course).
 
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Yes, the regular unfaced rockwool Batts are fine to use above your blockoff plate. I stuffed them up in the open space above my fireplace in the smokeshelf area and around my insulated liner.

I then got some of the foil faced sheets of semi rigid roxul from Grainger and made a blockoff plate with that. I also covered the back and sides of the fireplace with it and fully taped all the seams with foil tape.
[Hearth.com] Where to buy Roxul
[Hearth.com] Where to buy Roxul

Then, I made a metal blockoff plate and a series of metal panels with 22 gauge steel to cover the back and sides, and painted them with black stove paint to give it a finished look.
[Hearth.com] Where to buy Roxul

That part is not necessary, especially if you have an insert and will be installing the face plate on it. I had planned on leaving the faceplate off my insert to gain more heat in the room so I wanted the fireplace behind the insert to look decent. 4 years of metal working in a previous job years ago finally paid off.
 
Yes, the regular unfaced rockwool Batts are fine to use above your blockoff plate. I stuffed them up in the open space above my fireplace in the smokeshelf area and around my insulated liner.

I then got some of the foil faced sheets of semi rigid roxul from Grainger and made a blockoff plate with that. I also covered the back and sides of the fireplace with it and fully taped all the seams with foil tape.
View attachment 323126
View attachment 323127

Then, I made a metal blockoff plate and a series of metal panels with 22 gauge steel to cover the back and sides, and painted them with black stove paint to give it a finished look.
View attachment 323128

That part is not necessary, especially if you have an insert and will be installing the face plate on it. I had planned on leaving the faceplate off my insert to gain more heat in the room so I wanted the fireplace behind the insert to look decent. 4 years of metal working in a previous job years ago finally paid off.
Very well done! Like this as it is easy to work with than metal for the block-off plate.
 
Yes, it is pretty easy to work with. You'll want a good sharp insulation knife to cut it with.

Also, it's not cheap so definitely make a stencil out of cardboard first. Roofing felt makes a good stencil too if you have that laying around.

The other thing I like about it is with it's semi rigid texture and foil facing, it keeps fibers confined and bound in the insulation especially if you tape all the seams with foil tape so you don't have to worry about your stove's blower fan sending little fibers into the house that could irritate people with respiratory sensitivity.
 
What type of Mineral Wool should I buy for a block-off plate? I went to Lowes today and saw 3 different R-indexes. I understand the higher - the better insulation, but what's the minimum I would need?
[Hearth.com] Where to buy Roxul


Thank you.
 
The roxul in them is the same. The only difference is the thickness. I'd buy thinner and stuff as much as you can in there. You'll have plenty left over.
 
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