Decks, Patios, Porches and Docks - 2nd Floor 4x8 Deck Built on Floor Joists, Help

I have a small walkout porch/deck on the second floor of my house, a staircase takes you down to ground level. I'm needing to rebuild the deck because the wood is rotten. My problem is, the deck is built on the same joists that are in the house, they just extended the joists about 4ft outside when they built it, and the deck is there. The tops of those joists are rotten from 30 years of weather, so I think i'd like to replace them, but the easiest thing is probably just to double up on all of them with new wood and bolts. I cannot find any information on a porch or deck built like this to even know where to start. They have 2x8 blocks betwen the joists to block the cavity into the house, so I can't attatch the new joists to those. Has anyone seen or dealth with this issue? If i'm not being clear enough I'll give more information. I really need help on this.

Cantalievered decks ought to be banned. (just my opinion)

If it's possible, I'd remove the blocking and cut those floor joists off above the wall and head them off with a rim joist. Then bolt a new ledger onto the house and go from there. Support the deck with 4x4 or 6x6 as the need may be. You might not like the 4x4's, but since the alternative is removing the ceiling and sistering floor joists onto your current ones (and running into possible electrical, plumbing and HVAC problems) you're better off building a freestanding deck that attaches to the house. Make sure the new ledger gets flashed- most cantalievered decks leak for that one reason- they are quite difficult to flash properly.

I have the same issue with my 30' deck. House was built in 1969 and the floor joists were run out to support the deck. It wasn't flashed and they rotted off. The previous owners then installed a new 'ledger' by lagging it into the ends of the joists - but went through the cedar siding. Again, they didn't flash. Guess what...the cedar has rotted.

I'm at the point now where I have supported the first 8' of deck from below, and cut out the cedar, the lags and trimmed the ends of the joists -- luckily the wood appears to be solid. The new ledger is still in place, and it about 2-3" from the house. I am stumped as what to do next. I am partially thinking about cutting out the new ledger so as to gain better access to the house, and install it tight against the house after sealing the now exposed wood.

I agree that lagging it into the blocking is insufficient. Another option is to drop in posts and support it permanently from below.

I would like to discuss this more. Drop me a note.

I agree that the best way would be to cut the current joists off and put a new rim joist in. I just wanted to make sure that would be the way to go, I imagine a lot of cold air would come in the house the way it currnetly is too. What would be the best kind of saw to make a cut like this? You'd almost have to cut 2 inches inside of the exterior wall to make room for the new rim joist. so that it didn't stick out too far, or would that even matter? what do you attatch the rim joist to the ends of the floor joists with? i would think bolts so that it wouldn't pull out.

I used a sawzall to cut off all the junk that I had between the new rimjoist and the old floorjoists.

We may have to bore a hole in the blocking and cut out from there...I am partially considering doing this from inside the house as I have 2 patio doors over this mess..

I am going to let mine (ledger) stick out and flash it reallly well.

I think we have to attach it with countersunk lags. I say countersunk, because I will have to put a double ledger in to cover the current gap.

I have successfully used window tape for flashing before - assuming you don't have inspectors to worry about. I use the tar backed tape designed to go around windows - cost is about $0.25/foot and it's about 3-4 inches wide website (http://www.protectowrap.com/cat_btfbt20.php) . If you overlap, make sure the water never has to go up over a lip.

Yeah, i figured the sawzall would have to be used, just wondering if i can cut a straight line with it. I also have a patio door above this and below it, the deck spans the door exactly. I recently had to put a new door in upstairs and the wood under it was rotten, probably because of this type of porch as mentioned earlier. I cut out the subfloor under the door and put a pressure treated board down there, when I removed the subfloor you could pretty much see down the joists and the blocks they have installed. I think when I do this right, I'll rip out the blocking too, and bolt in some 2x10 or 2x8 1ft boards to the current joists to reinforce and give me some extra wood to grab when I put a new rim joist on it. That way I'm not attaching through the wood grain of the end of the joists, I can have the edge of a 2x8 or whatever I use to put a bolt into also.