I’m in the middle of having my south-facing 2nd floor deck renovated. The railing will be screwed to wood posts at either end and also secured the middle post (see photos). Because the posts are old and dried, cracking, etc., due to the harsh Arizona sun, the plan was to replace the two 4-foot posts. We just realized the posts are one piece with the posts below, so can’t replace it without a LOT more expense. This leaves me with treating the existing posts. The bottom section is fine, just the upper that gets the weather abuse. Is there a way to fill, seal, or cover these to withstand the elements? I haven’t decided on aluminum or wood railing. Thanks for any advice.