I have been doing a fair amount of research, went to several paint shops, visited Home Depot and Lowe's, yet could not get a clear answer that would help me with my project.

I'm in the process of redoing a pergola over the back deck of our mid century home. The pergola has a unique feature that consists of tiltable "blinds" which were made of 6' wood planks. These planks had been painted white. After eight years of ownership of this house the planks were severely bent and the paint was flaking and falling off.

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Per advice from the lumber guys I bought new cedar planks since cedar is highly resilient to weathering and bugs. Our house features a beautiful whitewashed wooden ceiling which is why I've been wanting to carry that look to the outside.

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After several discussions with various people I've landed at experimenting with solid white exterior flat paint and a medium base exterior flat paint. When I whitewashed the cedar with either sample they turned out exactly the way I would like them to look. The question I'm asking myself is whether a diluted or thinly applied paint would insufficiently protect the wood or potentially start peeling off earlier than I would like it to? I believe the zinc in the paint is what gives it the white color but I don't know whether it is what is protecting the wood or if it's the latex that helps with UV and water protection? Either way I'm unclear whether a whitewashed solution with exterior paint would be a good long-term solution. I would prefer not having to refinish 50 planks two years from now.

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I also inquired about whether I could add a secondary finish over the whitewashed wood such as a clear matte sealant. I believe a whitewashed paint is a non penetrating surface application therefore a secondary product would need to adhere to the paint, right? The guys at the paint store told me since it's an exterior paint adding a secondary product on top would not make any sense.

Alternatively, I was looking for other solutions such as a stain that would yield a lighter color. I have not found such a product. The stains that I have found either change the hue/color of the wood, preserve the existing color or darken the wood into a different color. Maybe I'm missing something there.

I also looked into traditional whitewashing using lime and salt however that approach does not seem to be weather proof and would wear off quickly.

Any help here would be much appreciated. Has anyone whitewashed wood for outside use with a resilient finish?

Thank you!