Wood preservative for gate - to be painted
We're having a new garden gate built as the other one was too badly damaged by termites and wood rot to be repaired. Redwood is being used for the gate. I think I want to use a wood preservative on the wood prior to primer and painting. We want the gate to last as long as possible, and I'll be better at regular maintenance on it.
Any advice on what wood preservative to use and where to buy it - I'm in Los Angeles. I asked at Lowes and they only had wood preservative that can not be painted, and only one brand. So not much selection.
Thank you in advance.