I agree with everything Spruce advises, especially in regards to a oil-based varnish working best for the space you described. If it gets really hot and humid then you definitely don't want to use a 2-in-1. Always do your research to make sure your top-coat will match. Storm System has a new "Waterproofer" transparent sealer that prevents moisture penetration and water damage. Might do the job, best of luck!