We are doing a home renovation and adding an attached dwelling unit to our home.

Per building code, the main house and the attached dwelling must be separated by an one hour fire wall that goes all the way from underside of the roof (i.e; into the attic) to the crawl space. Normally this is not an issue, but this is a renovation instead of new construction so there are existing roof rafters that run perpendicular to the wall which prevents the fire rated drywall to simply “slide” into place. The contractors solution was to cut the rafters back by a few inches, slide in/install the fire rated drywall, then installed a ledger board, then attached the cut rafters to the ledger board with hangers. That approach works on one side, but the other side of the wall has several pipes penetrating the firewall (which is when our contractor vanished - assuming he knew he messed up).

The question is: how can the ledger board be put up around the pipes (assuming notching the ledger board) without compromising the structural integrity?

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  • My builder forgot to put a fire break in our floor trusses (code apparently requires one to run midway through the house the full length). The inspector caught it on the rough plumbing inspection. They installed the fire break, but since they had to go around pipes, some of it was cut and spliced. They used a fire rated joint compound at the splices. Here's an example: usg.com/content/usgcom/en/products/walls/drywall/sealants/…
    – RetiredATC
    Aug 6 at 16:27


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