ᐅ Which insulation wool is best for the roof?

The roof construction for our new single-family house will be as follows:

- Clay tiles
- Wooden battens
- 60mm (2.4 inches) soft fiber underlay boards
- 200mm (7.9 inches) insulation between rafters
- Vapor retarder
- Counter battens on the inside
- Insulation between the counter battens (depending on the thickness of the battens)
- Plasterboard or similar...

For insulation, a layer of 200mm (7.9 inches) thick mineral wool is planned. We are considering “Klemmrock.” Does anyone know of a better material or any better solution?

Hello Baukoller,

"Better" in what way? Everyone has their own idea of "better": for some, it would mean a better U-value, others prefer only natural fibers, ...

But your choice – 035 rigid glass wool board – is already good; there is also 032 glass wool from Isover (so a slightly better insulation value), but whether that makes a noticeable difference is questionable.

Ok, mineral wool is a widely used insulation material today. In terms of thermal performance, the insulation rolls like Klemmrock or Isover are quite effective. From my point of view, the downside is: what happens if a roof becomes damaged and leaks due to hail, and the underlayment membrane also gets holes? Then your glass wool will absorb water 🙂
For that reason, I prefer to use Styrofoam, which also comes in flame-retardant versions.

Hi Paule, that may be true, but most tradespeople use mineral wool, and combined with Paracell boards, this is also a practical solution. You always have to be careful with the question of vapor barrier, so everything should be sealed properly here, which is something that is often done carelessly.

I find this roof structure quite good. For me, the important factors are the insulation value and moisture protection. I think using insulated rock wool in slab form is a good choice for that.

Hello,

I also find this construction quite acceptable. I have already worked with this type of compressed insulation wool from Isover. This 035 Ultimate offers excellent thermal insulation. This mineral wool is also easy to work with.

Best regards