I inquired of DAP last week on the Top & Trim Adhesive for use on Sintra board (PVC Sheets) which I am using for all of my interior panels. Jessie, one of their Product Specialists responded with: Unfortunately, we do not recommend the DAP Landau Top & Trim for applications involving PVC or plastics and it may damage some of these surfaces. Testing is recommended before using in a large scale application.
Dan, I just read in this post and in a previous thread that you use this on PVC to foam, fabric, vinyl, and/or leather without an issue. Based on DAP's response, I was about to go out and buy traditional backer board and redo my panels... please tell me I don't have to do this!