Cedar post extension - should I seal the joint somehow?
I recently added extensions to the top of the red cedar posts in my fence (we're adding lattice to the top of the fence for additional privacy). I used what I think could be referred to as a "dutchman splice" (see my rough sketch below).
Between the original post and the post extension, there is about a 1/8" gap (I used some cedar shims to get the extension perfectly plumb and in line with the original post). I secured the extension with wood glue and two screws on either side - it's pretty solid now, which I'm happy about.
I would leave it alone. If you try to seal it I fear you will create more problems than you may not even need to solve. Trying to caulk or seal it you risk an imperfect union into which water could seep and freeze. Let it contract and expand. You have like materials joined together so this should happen at the same rate.