how stiff are Rockwool 1" insulation boards?

[Itsjustdirt]

I've worked with Rockwool batts, but I'm wondering how stiff the Rockwool 1" comfortboards are? I don't have access to them locally and would like some insight from someone who's worked with them before? Are they pretty stiff? Will it sag if supported on either side of a 24" opening or would it need to be suppored in the middle as well as on the perimeter?

 

[jack stand]

I don't know but you know how heavy the batts are and I'd guess no based on that. Rigid foam might be the answer and probably offer a higher r value.

 

[Voi]

I can't seem to confirm at the moment but I think either Rockwool or another company makes a mineral wool board designed for application of EIFS and I believe it's more rigid. As far as I know it only comes in 2" or thicker panels.

I have seen the regular Comfort Board referred to as semi-rigid, for what it is worth. And installation videos show it being slightly flexible.

Are your talking about wall or ceiling spans at 24"?

 

[CombatNinja]

They are slightly flexible but certainly would not sag over a span of 24".

 

[gahrajmahal]

I used 1/2” x 4’ x 8’ homasote boards on a basement ceiling. It is stiff and adds some insulation along with sound deadening And can be painted.

Homasote® 440 SoundBarrier® 1/2" x 4' x 8' Sound Deadening Panel

440 SoundBarrier® is a special-density, structural board made from 100 percent environmental Homasote® cellulose fiber, a homogeneous composition manufactured with uniformly distributed protection against termites, rot and fungi, and resistance to moisture. It also insulates with twice the...

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