I'm building a live edge bench in memory of a loved one, and would like it to last as long as possible while weathering the elements year round. I live in Pittsburgh, PA, which means we get occasional sunny summer days in excess of 90 degrees, but of more concern are occasional sub-zero (C) temperatures and lots of snow and ice in the winter. I'm also concerned about bugs.
The bench will be made from several bookmatched slabs of live-edge Cherry at approximately 1.5" thick. That includes the bench, seatback, and side/legs. Hidden lateral supports will be made from pressure treated 2x4 lumber.
I planned to do nothing to the pressure treated 2x4s. I planned to cut and sand the live edge slabs, then have the dedication laser-engraved. Then apply 7-10 coats of UV-resistant outdoor poly-urethane. Then anchor together using outdoor deck screws with a dab of 100% silicone over the screw holes (they will be hidden).
What other measures should be taken to keep this piece protected from the elements? Is there any sort of chemical that should be applied and allowed to seep into the wood? Keep in mind that any treatment to the visible decorative areas must not negatively impact the appearance of the wood.