16-0819 v3.0/Homestead Remade/Mineral Wool Insulation


Our team is looking for clarification on the use of Mineral Wool Insulation in Living Building Challenge projects. We have searched the dialogue for other instances of the products use and have read the materials handbook specific exceptions on the product. We are having a difficult time processing the information as it pertains to our case.

1. We would like clarification on the language of the exception as it appears inconsistent:

Page 14 of the Materials Handbook I10-E9 3/2013 states:

Phenol Formaldehyde in Mineral Wool Insulation is allowed in rigid mineral wool insulation forexterior applications (such as rain screen assemblies or foundation insulation). While rigid mineral wool insulation does contain some formaldehyde, most of the formaldehyde is eliminated in the production process through a chemical reaction and high heat. Rigid mineral wool insulation installed on the exterior of the building possess less risk to humans and ecosystem than rigid foam insulation products, which almost always contain HFRs and use blowing agents with high global warming potential.

Page 16 Specific Exceptions to Red List chart states:

Phenol formaldehyde allowed in mineral wool insulation

We take note of the words “exterior applications” and “rigid” on page 14 and would like to know if this is the intent of this exception or if phenol formaldehyde is actually allowed in all mineral wool insulation per the chart on page 16?

2. In our specific single family residential project we would like to specify Roxul products in three separate locations:

A. For exterior rain-screen application

B. Below slab rigid insulation

C. As we will be building upon the existing foundation walls we would like to specify Roxul CavityRock rigid board for installation on the interior side of the foundation (in lieu of extensive exterior excavation). It seems one could consider either the foundation insulation within the building envelope or outside the conditioned envelope as there will be interior basement framed walls with additional insulation separating the Roxul from the living space.

Are the above listed three applications acceptable for mineral wool insulation products?


Mineral wool insulation products containing phenol formaldehyde may be used for exterior rain-screens and below slab rigid insulation under I10-E9 Phenol Formaldehyde in Mineral Wool Insulation. Both of these applications are exterior, and therefore pose less of a risk to occupant health.
Installation of the Roxul CavityRock rigid board on the interior of the foundation does not meet the requirements of this Exception because it is an interior application. Mineral wool insulation products used in interior applications pose a higher risk to occupant health because of the potential for the products to off-gas phenol formaldehyde. However, if the team exercises Due Diligence and a Red List-free product can not be found for this application, the team may use this product under I10-E1 General Red List. 

Post ID 6031

Still need help? Contact Us Contact Us