Junk deck job

My 1860's home has 7 y.o. deck from a previous owner, about 200 sqft. Made with all treated lumber and 2" lumber decking. It strikes me as not supported very well. The deck's 2x10 inside girders are flush to the side of the house, and are bolted into the sill beam of the house, right above the foundation. No effort to manage water penetration between the girders and the house trim. They also put in 2x6 vertical supports, sitting on concrete blocks, for these inside beams, spaced every three feet, and yes, right at the same places they bolted the same girder to the house sill beam. (First question - what's the IQ of the dingbat who did that?) The outside girders are sitting on 4x4 vertical lumber supports, also sitting on blocks.

No problems seen yet - but this strikes me as a bad handyman job that has a good chance rotting out sill beams on the old house. Near this part of the house I've found one corner sill beam that has serious dry rot, so I'm worried that there may already be issues with these beams. I'm thinking that maybe I need to tear the deck down, check the sill beams and get the house sealed up, and rebuild the deck with the supports separate from the house and with some gap between the house and the deck. Is 'stand alone' build the normal way to go? Should I just smear everything with calk and walk away from this? Maybe an easier but ugly approach like setting the decking so there is a gap 2" in from the side of the house, then flashing in roofing rubber under the clapboard and to the gap so water skirts the inside of the girder?

Thanks! B.

 

I can't comment on the structural aspect of things - the description is hard to picture and its difficult to offer solutions to something you can't actually see. But I would say that if you are going to attach a ledger, through bolts are the best way (not lags). Spacing the ledger away to allow drying would have been better, but there could be a flashing that you can't see. Or maybe not. At any rate, if you can remove the floor board that runs along the house, you can inspect the top of the ledger to find out. If there's no flashing you can put one in. It should go up and under the siding (and building paper) and then out and over the ledger. I like to fold my flashings down over the ledger too, like a drip cap on a window.

This would solve your worries about the ledger rotting the rim joist. The rest of it you'd almost need to submit some pictures for us to see what was done.

 

It sounds as if they may have had some bounce in the flooring and retrofitted the 2x vertical supports. 200sf is not alot of deck space, and could be rebuilt rather easily. Especially if you detect any rotting on the house. The deck can be rebuilt, the house needs proper protection, as XSleeper says, proper flashing is mandatory. Now, whether you choose to rebuild the deck properly (first choice), or try to flash it in place, you need to do it before alot more damage happens.