I'm just wrapping up 2, 4x8ft carraige doors that will lead to my shop. Theyre 8/4 poplar as I am planning on painting them white to match the rest of my home. My question is what products to use to adequately protect the doors against the elements.

This will be the first time in many years that I paint a project and I'm clueless as to what I should be using. I'd like a semi-gloss finish if at all possible.

Thanks in advance for any replies

PS