I now have the rotted t&g flooring off, about 1/3 of it. I can also now see the structural framing. It's not ideal. I found the original blueprints. Apparently the builder had his own ideas. There is a 2x10 screwed to the siding of the house -- directly to the siding. There is an opposite 2x10 screwed to the columns. Across those, 2x8s are nailed every 16" or so. The columns "mostly" sit on concrete. I say mostly, because some are pretty much right over a 6" diameter concrete pillar(?) that seems to go down fairly deep (it has not heaved much). However, atop that they poured a larger, 12" or so, 5" thick pad. Some columns sit pretty much atop the 6" pillar, some are more offset. Some columns are dangling -- not touching, while other columns are far enough off center that the bigger pad is now tipping. The 12" "pads" really appear to be doing nothing -- either they are below the columns, tipping, or the 6" pillar has pushed up through the 12" pad. I'm no structural engineer, but it seems to me the right approach would have been to pour an 8" or 12" diameter pillar to about 4' depth and center those columns right over it. Not?

Then the "ledger" and opposite side 2x10 is just screwed in place. Under a few on the columns they nailed an additional 2x board under that to better support the 2x10. "Joists" are then nailed across and the flooring is installed parallel to the house -- which makes a nice trap for all the water that gets into the exposed grooves. From what I've read and saw on the plans, the flooring should be installed perpendicular to the house, so with the slope away from the house, water would run out of the grooves. The plans actually have the flooring structure built atop the concrete pillars -- and then with joists running parallel to the house and the flooring perpendicular. Mine is also built with untreated lumber, whereas the plans call for treated, and given the minuscule cost difference, I'm still scratching my head about this. The plans then had the porch columns sitting atop the porch floor. My columns run down (mostly) to the concrete pillars, and the the floor structure is screwed to the columns. Oh, and the columns in a few cases extend below grade, so the 6x6 cedar column is buried in the dirt a few inches. The rot there is not too bad fortunately.

Finally, there is a 2x10 that was notched into the columns around the outside of the columns (the other is on the inside of the column and is just screwed into place -- this is the one that supports the floor). The one on the outside just extends the floor out those 6 inches so it "looks" ok. Where they really went wrong is they just nailed in a board between those two 2x10s and put flooring directly atop. That rotted real nice.

So where do I start? Tearing it all apart comes to mind, but that's a major expense. Next up I'm thinking to replace all rotted 2x10s (most) and 2x8s joist with treated - paint the exposed area of any non treated wood, use blocking between those inside and outside 2x10s, and then nail down flooring that has been painted on all 6 sides. Later I'll prime/paint the visible treated 2x10s.

If they would have extended the joists another 6" they could have just attached them to the outside 2x10s that are NOTCHED into the columns - which would have saved all those interior 2x10s that are just screwed in place. I'd also consider that, but I'd have to pull up all the floor and replace all the joists. Or could I somehow sister some 2x8s to theirs and extend mine over to the notched 2x10? I'm not sure how I'd join my 2x8 to their 2x8 in a way that was strong enough and didn't require nearly replacing the entire 2x8 joist.

My concern also is the concrete the columns are sitting atop. Several are far enough off center, that I'm concerned I do not have a solid place for the columns to rest.

What's the right way all of this should be done? What's a reasonable way for me to remedy what I have?

Thanks so much for any and all guidance. I can post some photos also. Kind Regards, Kevin