Roofing felt or plastic spacers under wooden posts?

[fribygg]

How much do you think needs to be in between there then? Is 7-10 millimeters enough?
The hope is that it might be enough to lift up with a jack and then add thicker sealing felt or those spacers. I don't think more than 10 millimeters is possible without having to cut, but maybe 10 millimeters is good enough?

Just like under a sill on a concrete floor, it's about breaking the capillary action so that moisture doesn't rise into the wood. It's enough to lift a few mm and place sealing felt underneath.

 

[z_bumbi]

Before you painted, you could have unscrewed the lower screw and filled with oil until it no longer absorbed, or until you got tired.
Screwed the screw back and waited a couple of days.
Painted with oil paint.

However, since there is already syllpapp under the post, the difference is mostly academic. The only problem with the current solution is if the post was damp and the paint you chose is very dense.

 

[ToRy]

I think one or two layers of syllpapp should be enough, so if you can lift without needing to cut, you'll avoid a lot of work. Then I think it might be good if you scrape off the paint you've applied to allow the wood to breathe. It can't be that much work. It doesn't need to be 100% bare wood.

 

[Klabbis 3000]

Can one believe that these are suitable for permanent packing of wooden poles?
Their website states that they are not intended for permanent packing of concrete elements, but there are much larger loads in those cases.
https://www.distex.se/kilar---pallningsbrickor/pallningsbrickor