Piggybacking on my previous question about the headers in a skylight frame (Double header for skylight frame), I'd like to know if it's required to sister the uncut joists on either side of the skylight well?

As a reminder, my ceiling has 2x6 joists 16 OC. And the flat roof which is 20" above the ceiling has 2x6 rafters 32 OC. There will be no cuts made to the roof rafters.


If you have the opportunity to double them up, then sure...more is more. Otherwise no, it's not required as you're only carrying one rafter and not creating a dormer, which does indeed require double or more for the end rafters.

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