In carpentry...What is a sister?? (??)?

Question

there is a carport and they say they need to replace the sisters right under the carport.

Thanks a lot!

Answer 1

Are you sure they did not say "Cistern" in regards to a septic system?

Is the carport wooden? They may have meant sister joists, which are joists that are directly next to each other and touching as if they were one joist.

Answer 2

It`s additional support added to any member(typically along side).

This term is not exclusive to joists only!