Is polymeric sand necessary for paver joint?
I live in the Pacific Northwest also. I have done several paver walks, I have used regular sand and polymeric sand. What I have found is a good even base is the most important part of the job. Regular sand tends to need a new bag about every 3 years and polymeric is going on 5 but will need an add this year. For me both tend to grow grass because our horses kick up a lot of dust in the arena on hot days then things grow, not bad but it happens with both. Make sure your base is even and the pavers are uniform height for the best long term results. I used 1/2" crushed quarry 1-2" thick under my areas and compacted it drains well and the pavers don't move. Good luck on your project.