Is it only the white post that needs to be replaced? Or is there something more? What is it supporting?
If it "only" supports a pergola or something similar, I would do as you wrote. Put up a temporary support and replace it.
With an overview picture, more concrete/detailed advice can probably be given.
If it "only" supports a pergola or something similar, I would do as you wrote. Put up a temporary support and replace it.
With an overview picture, more concrete/detailed advice can probably be given.
Alright then.
As you wrote, just place a temporary support about half a meter out from the post you want to replace. I would lay a plank piece on the decking to spread the load and then measure the distance to the beam. Cut a piece of lumber that is long enough to require a bit of "persuasion with a hammer" to get into place and then attach a couple of pieces of wood on the side of it as a "fork" around the beam. Perhaps put a screw into the hidden side of the beam so the support doesn't fall if the pressure releases. Then an angled screw or nail down into the plank piece to keep it in place.
After that, simply remove the rotten post and install a new one. Once it is anchored, remove the support.
Make sure the new post is properly oiled at the end grain and place a piece of sill paper or similar underneath so it doesn't absorb moisture more than necessary.
As you wrote, just place a temporary support about half a meter out from the post you want to replace. I would lay a plank piece on the decking to spread the load and then measure the distance to the beam. Cut a piece of lumber that is long enough to require a bit of "persuasion with a hammer" to get into place and then attach a couple of pieces of wood on the side of it as a "fork" around the beam. Perhaps put a screw into the hidden side of the beam so the support doesn't fall if the pressure releases. Then an angled screw or nail down into the plank piece to keep it in place.
After that, simply remove the rotten post and install a new one. Once it is anchored, remove the support.
Make sure the new post is properly oiled at the end grain and place a piece of sill paper or similar underneath so it doesn't absorb moisture more than necessary.