Bitumen paper under post larger than the post or just under the post

[JanneSjo]

I am going to install a post (actually a 45x120 beam, 2 pieces) on an existing horizontal impregnated beam.

I was thinking of putting paper under the post and I'm wondering if the paper should extend beyond the post or just be underneath it.

Maybe I'm thinking wrong, but if the paper extends beyond the post, moisture might run down onto the paper and under the post.

Therefore, I believe it's better for the paper to be exactly the size of the post.

Am I thinking wrong?

I considered having plastic spacers underneath - but couldn't find any at the hardware store or Jula.

 

[Nimajneb]

You only need cardboard if you place the end grain against something like concrete, not wood.

 

[JanneSjo]

isn't the pappen supposed to prevent it from absorbing moisture so easily?

I think there might be moisture on the horizontal beam.

is there any disadvantage in having papp between the wooden post and the horizontal pressure-treated beam?

 

[JOW]

If it feels better, place a cardboard sheet under the post, the same size as the post.

When I placed my posts on the veranda, I sawed off 7mm rings from 75mm drainage pipes, then screwed from underneath into the post.