18-0807 v3.X Window Veneer Adhesive Transparency


We would like to request exemption I10-E4 (proprietary ingredients) for a specified window product. The project is a single family residence registered under LBC 3.1. The project specifies fiberglass windows (due to pacific northwest climate, chosen for longevity) with wood interior. After talking with manufacturers about issues related to solid wood interior/fiberglass exterior we selected a wood veneer on fiberglass arrangement (lessen chance of moisture/condensation issues or warping in the future). The specified window frames are a declare product (Duxton fiberglass windows) and the veneer is solid, sustainably sourced fir.

The only element of the product that does not have full transparency is the adhesive used to attach the veneer. However, the manufacturer has provided and SDS sheet listing all potentially hazardous materials within the adhesive and it contains 2.5 % di-phenylmethane 4-4diisocyanate, CAS: 101-68-8, but no other hazardous materials. Cross-referencing the CAS registery, di-phenylmethane 4-4diisocyanate is not on the red list and is allowable by LBC criteria. We have a letter from the manufacturer stating that 97.5% of the adhesive is proprietary AND that that mixture contains NO RED LIST CHEMICALS.

We then contacted three additional window manufacturers regarding comparable products and they either use the same adhesive for veneers OR their window frames (even fiberglass ones) contain red list chemicals and are not LBC compliant. Letters advocating for product transparency and elimination of red list chemicals were sent to these manufactures as part of our process.

The window manufacturer we would like to use (Duxton) takes their Declare status very seriously and has been dialoguing with the manufacturer of the adhesive to move toward declaring the wood veneer window product as well. We feel that supporting them in that effort and moving ahead with ordering and installation of the their product would not only meet LBC criteria, but would support more declare products being available for future LBC projects. Thus, we are requesting an exemption as already stated. Please advise. Thank you!


If the product has a Declare label indicating it is either Living Building Challenge Compliant or Red List Free, the Declare ID number is the only documentation required. In a future case where a product is not in Declare and is withholding ingredients, then use of Exception I10-E4 Proprietary Ingredients requires the team look for alternatives and advocate to the manufacturer of selected product to be fully transparent. Use of I10-E4 does not have to be approved in advance by the Institute. 

Post ID 7142

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