My mission to find mineral wool
It’s sometimes easy for us to let readers know about new products like rigid mineral wool insulation (written by Alex Wilson in FHB issue #208, click here), but for our readers, finding a distributor for those products is a whole different matter. So, for a basement remodel that I’m currently working on, I thought I’d put myself in the readers shoes.
Rather than using 3/4″ plywood, 1/2″ drywall, or some other means of draft-stopping the new basement walls (necessary to prevent potential fires from jumping from the basement walls into the floor joists above), I began a hunt for rigid mineral wool that I could cut to fit between the top plates of the new walls and the existing mudsill, and then foam any gaps with firefoam purchased from EFI (a great website, by the way).
Having already heard that rigid mineral wool was hard to come by in the US, I figured this search would be a tremendous hassle. Turns out, Roxul makes it pretty easy. I went to their site, clicked ‘find a retailer’ and was greeted with an interactive google map that listed suppliers in my neck of the woods.
Easy enough so far, but was the item a special order? I hate that…especially when I only need a small amount.
So, I got in touch with the local lumberyard yesterday afternoon. I got an email back this morning. Apparently, the only Roxul products they keep in stock are batts (3″ x 15 1/4″ x 47″ @ $5 each; a great price), but they also have another brand of mineral woold rigid boards, 2’x4’x2″ thick @ about $7 each.
Now to find out whether Andy Engel was right when he told me that working with mineral wool was worse than fiberglass…
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The big box stores and lumberyards up here in the region around Canada's national capital (Ottawa-Gatineau) only stock the residential batts too.
The kind of Roxul products you are looking for are more likely to be found, around here anyway, at suppliers who sell to contractors working on the commercial side of the business; those suppliers who sell to contractors doing flat roofs or apartments and office buildings. It may still be a special order, but it might be a special order from another location of that supplier. And they tend to ship back and forth between locations pretty regularly. I can think of Convoy Supply and Givesco in Ontario and Quebec as two options though that won't help you down your way.
Hi Andrew,
Thanks for the comment. I should clarify that I was surprised any of the lumber yards around here (in the Northeast) stock ANY kind of mineral wool. It's just not used for residential construction in the States. I know it's a common find in Canada, so I'm glad to see that Roxul and some other companies are pushing hard to move into the States as well!
I have installed tons of the stuff and find it easier to work with than fiberglass, since it's stiffer. The trick is to find a long, finely serrated bread knife to cut the stuff with. It's also not so itchy or irritating to the lungs, but I still wear a mask.
"Now to find out whether Andy Engel was right when he told me that working with mineral wool was worse than fiberglass..."
Having installed both, I'd prefer the Roxul. It's a little more solid and holds together pretty well.
People's past impressions with mineral wool, which is a pretty old (archaic) term, may not be valid. I recall coming across old mineral wool during renovations and Roxul isn't the same stuff.
Roxul can be now ordered from both large home center stores. I just removed all the blown in fiberglass and cellose in my attic because I needed extra storage space. In addition, I wanted to use batts for ability to make electric and plumbing changes easier. Lastly, I also used opportunity to air seal attic.
Since the house in very old, I am not sure how safe the previous blow-in products were. Every time I entered the attic, I would leave with a sore throat and continuous cough. What I like about Roxul is the R-value per-inch is higher than fiberglass, it fits tight to studs, it’s not itchy, and it doesn’t seem to produce a significant amount of floating material.
I am installing 1400sq/ft of R-23 Roxul. You will need a 10” bread knife.