My hairdresser was concerned that the top of my grey hair was damaged by the sun. I am not a great hat wearer but even I have found recent sunny days a bit much. I had a couple of sun hats at one time, picked up at the last minute at airports for foreign holidays, but I can not think where they might be at present (or if I donated them to charity when we moved). So I used my husbands canvas sun hat as a pattern and using the overlock stitch on my new sewing machine to make a quick hat for gardening. I had made some "bucket" hats for my grandchildren using a similar pattern but they were fully lined.
I doubled up the brim with a plain yellow cotton lining but left the crown as a single layer.
This is one of the grand children's hats. I saw one like it priced at £10 in the posh childrens shop the other day!