I need some advice on exterior insulation. After researching breathable materials for months on end, the only breathable material I found that's offered in my country (Bulgaria) is rockwool. They recommend installing rockwool with 'special' glues (For sticking on the wall) and plasters to be put on top of it (supposedly much lighter than sand and lime mixture). I would rather not use these glues that are toxic but they say that using only screws is not enough. I am wondering:
1. about the toxicity over the long run of rockwool (the dust that can be dispersed from it and breathed in)
2. whether I can use an alternative non-toxic, breathable mixture (clay?lime? caseine?) to stick it to the wall, and on top of it
It's certainly possible to fix rockwool without glue.
Do you have a specific "wall pie" (materials that form layers of wall) in mind?
Did you intend to have rockwool as outmost exterior layer? It's a common practice in my area (Russia) to fix and cover rockwool with sheets (plywood, OSB, plasterboard). But your general wall plan may hint a better choice.
posted 3 years ago
The house is now brick (25cm thick) WE prefer to plaster on top of the rockwool as it is cheapest, but is it enough to fix it to the wall without gluing it to the wall or with non-toxic glue if there is any that we can make/
posted 3 years ago
They know better, but I can't see how glue could possibly help due to soft nature of rockwool. It would stick a thin layer of rockwool to brick and then hard impact easily tears off most rockwool away, leaving thin layer glued to brick. I'm trying to say that rockwool will never provide any structural strength, but it will also never fall off if it has something ouside. So gluing rockwool to brick, in my opinion, is a waste of glue.
I think plaster would hold rockwool, but then what would hold plaster?
You could use plastic net to give plaster some frame. And you could fix that net to brick using something like nails.
Consider strength of such plaster exterior against children games, weather, accidental impacts, etc.
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