It is wise to have a protective sealant brushed on your wood before the harsh winter/summer set in.

If your deck gets a lot of sun exposure, consider using a wood sealant that has a UV protection agents inside. Wood sealants that are clear usually don't have UV protection inside. These sealant are better for a shine.

Wood stains that have a water sealer and UV protections are better for changing the color of the wood.

To protect wood decks or other structures exposed to severe heat and sun exposure, use an acrylic stain with transparent iron oxide or opaque pigments

This is a beautiful piece of work, wonderful view too. Good job
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