Rockwoll is the worst. It handles poorly, it is not renewable, it is energy intensive to manufscture, if its older than 1970 it is likely manufactured with asbestos and most importantly it had those tiny scratch fairy's that attack you for days to come.

I learned recently that the phase shift of rockwoll is terrible because of its low (thermal) mass. Meaning that it will become saturated rather quickly and then dissipates heat onwards. For a few years (20?) there has been an alternative made from wood fibre that is bound together by some degradable agent and impregnated with amonia salts (not great but loads better than the alternatives). it is recyclable as I'm the company picks up the offcuts and reuses them. But most importantly its high mass (15kg per m²?) Is perfect for home roof insulation because it keeps most of the absorbed energy for about 12 hours before it's saturated. Keeping you cooler during the day and radiating inside and outside at night. Its called gutex and is very versatile.

Edit: it comes in fluffy and light style too as gutex thermowall. More like rockwoll I guess I can't recommend it enough. There are generic manufacturers too I am sure.

Thanks. I just figured this was some obscure building material I had never heard of. Maybe Icelandic in origin.

Please do. Before it's too late.

Water in any kind of insulation or basic material (even concrete) would be bad in terms of insulation properties but also in lasting damage to the building substance.

It is usually in between timber frames. Standalone I haven't encountered it.

Edit: it is foremost used because of the great insulation and room climate properties. Also it is renewable and local. So a bunch of pluses.

I watched a strawbale building demonstration 20 years ago where they torched a stuccoed strawbale structure that had no treatments: the fire reached over 2000°f and when it was cooled, they cut open the stawbales and showed the fire didn't burn the bale more than an inch deep. They really do not burn due to the lack of oxygen.

Water on the other hand can rot out a whole wall if it's not sealed.

Then you violated the building code. Regarding fire and arguably more importantly air tightness to prevent condensation and resulting water damage.

In attics its mandatory to do a blow out test where you create overpressure and search for air movement and leaks with a smoke machine.

Rule of thumb is outer walls wind tight, inside perimeter walls air tight. (Diffusion open)

People in construction know what they're doing and in general know what they're talking about.

Unfortunately, that excellently constructed home they spent so much effort on will still be sitting there in 5, 15, maybe 50 years from now. And all that time it's definitely not getting all it's proper maintenance, and will slowly be dropping in quality.

I doubt these buildings would go up hindenburg style, but after a decade or two of being lived in, fires will not be as easy to put out in a home like this.

Source: not a construction worker, but have worked in construction for a few years here and there and have been working with fire for several decades (and working to make fire safe to handle and trying to fireproof a couple garages)

Do you know if the straw is treated as well?