Reply by doughan

what ssnvet said …..sealing the ends won’t do much to the rate of rot but speed it up…...it will still get wet and the sealer will hold the moisture in as well.

ask restoration carpenter what happens to fir beams that are painted.the paint wearout on top before the side and bottom allowing moisture in and then it won’t dry because of the paint.wet wood rots faster.
set it on rock and seal the whole piece of wood or don’t seal at all.sealing just the bottom and a little up the sides would be like wrapping it in a plastic bag.once the water is in it will stay