Due to increased risk of corrosion, do not install Elevations within 3,000 feet (.6 miles) of any body of saltwater or under the surface or within the splash zone of any body of fresh water. Any such installation will void the limited warranty.
Not really, just clean the surface of any debris or dirt. The tiles are ready to install right out of the box. However, if the tiles are installed directly on the ground, then a weed control fabric should be laid down first.
Most weatherproofing should last at least two years. However, if your deck gets excessive sun (dryness) or no sun at all (mildew), you may need to service it more often. If you use a good weatherproofer and your deck gets a good balance of sun and shade, it could last up to five years.
Typically oil based finishes dry to the touch within a few hours and can be walked on in 24-48 hours after curing. Latex finishes typically dry within 2-3 hours and need a full 48 hours to cure. You would be amazed at how quickly oil finishes set. Often passing showers do not effect these finishes after application.