Went up to in-law family cottage on Lake Sabago in Maine to plan ahead for summer work (ain’t cottages fun?)  Crawled under cottage (6 bedrooms, 3 & 1/2 baths, no heat) to look at joists for potential floor replacement.  Found joists and subfloor ok.  Started to crawl around and inspect posts.  Four of the perimeter posts, although resting on concrete piers, were buried under pine needles.  I brushed them away, stabbed at the bases with my awl, which went in to the hilt (or handle.)  The inside corner post is the worst.  I estimate that only 25% of the original 6×6 is still structural.  See attached.

So I have to replace 4 posts, and to replace the inside corner post, I have to jack both beams from under the house.  To be honest, I’m not thrilled.  Scared, you might even say.  I’ve replaced posts before, I have 4 20 ton screw jacks and more than ample cribbing and blocking.  My questions are:

Do I do a one-for-one post exchange?  (I intend to install steel standoffs to prevent this from happening again.)

Or do I jack up as much as possible and replace what I can?  (I was thinking to use 4 jacks and replace the 3 outside corner posts first.)

Is there any way to replace the inside corner post without having to crawl under and jack up the beams?  (Wishful thinking, as the beams, 6x6s, are NOT continuous, but are scarfed at the inside corner.)

The structure is a single story stick framed addition attached to a much older two story building.  And to be honest, the addition over the rotted posts is in much better condition than the rest.

Any suggestions are welcomed.

Thanks.

Edit, sorry for the attachment, I’ve been fiddling with this program all morning trying to get it sized right, with no luck.  I’ll take a hammer over a computer any day.  A hammer TO the computer sounds even better.