Hi, the SF Dept of Environment is doing some surplus construction materials studies there are surveys for designers and contractors. They are looking for a wide array of responses, so don't worry if you don't live in that area!
See link for contractor survey if you are interested:
https://formfacade.com/public/110969220693360221062/all/form/1FAIpQLSei5P2sgPeshelD5UzA2I7-0bMNHA6SpwJnm4t5YSUFAiqAMg