Foundation external project done, now what…
user-1135248
| Posted in Green Building Techniques on
My crazy project to partially wrap the foundation exterior in Roxul
is finished, followed up by the inevitable detailed writeup.
The TL;DR is that after evaluating the viability and building-science
soundness of the idea, I covered all of the exposed block wall and
some way into the dirt with 2″ ComfortBoard. Lotta work, and some
fun problems to solve.
The question is … other than changes in moisture profile [which
I don’t really expect to be significant], what else should I be
watching out for in the seasons ahead? I’m not particularly
worried about it, but there might easily be some major point
that I didn’t consider.
_H*
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Replies
Hobbit,
My favorite sentence from your account: "I spent some amount of time sorting my rocks in a truly OCD fashion, into a nice size-graded pile..."
Nice job. Are you going to leave the mineral wool exposed to the elements? Or do you have a plan to protect the insulation on the exterior?
.
I considered something like 1/4" hardware cloth, but it would have
needed some attachment method likely more intrusive than the glue.
Can't be metal or cememt-board or the like, with the need to
dry to the outside. After seeing the test patch survive as it
did I figured the rest will be okay for the healthy long term.
Just like that pile of rocks sitting out in the weather will be
fine on its own, I expect the Roxul [also rocks!] will as well
and if some part takes damage, I've got a good stash of repair
material on hand.
_H*
Great write-up. I'm not sure I see the need for drying to the exterior. My wild guess is that by removing contact between the soil and the block wall, you have dried it, and that covering the Roxul with sheet metal or something similar would protect it without causing any problems.
Hobbit,
In my experience, mineral wool is rather fragile. I would worry about physical abuse from weed-whackers, lawnmowers, wheelbarrows, and such like. But it's an interesting experiment to leave the insulation exposed.
I just got done doing a similar project with 4" of comfortboard, 4' below grade portion of my home. I used 1/2" hardie cement board covered with a stucco type coating in cement color. It turned out great. I'm in zone 4, central, so we will see if freeze affects it as I didn't use a rainscreen gap.