Hello everyone,
I am doing some major work on a deck in the San Francisco Bay Area and I would like some advice. The floor joists from inside the house extend out about eight feet from the siding to become the deck joists. There are some cantalevered 6×8’s, but most are 4×8’s that are supported by a header resting on some columns. Some of these joists are rotten and need to be replaced. I think the easiest way to do this is by removing the decking, cutting the existing joists back to the load bearing walls of the house and then bolting new pressure treated members to the existing floor joists inside the house. I would have to cut into the ceilings of the house to do this, but it is a lot easier than tearing out a floor.
My question is how far back should I overlap the new deck joists to make it structurally sound?
Thanks
Replies
Why can't you just bolt a ledger on the house and hang your joists from joist hangers while the other end sits on the outside header that are held up by the columns like you described?
The easist, and least expensive way of accomplishing your repair, is as Joe recommends; cut them back to the wall and remove the pieces of old band joist, install a new band joist and attach the old joists to the band inside, then thru bolt a new ledger to the new band. For grins, I''d attach the band using lags into the joists as well as thru bolting, depending on any overlap between the new band and new ledger.
Otherwise, as you said, you'll need to rip open the ceiling to sister new joists (pressure treated, right) and who knows what you'll run into then; wiring, lighting, pipes, etc. that could quickly turn the job into a quagmire.
Make sure you flash the ledger well and use copper.
Good luck.
Hi Nic,
I plan on implementing your solution! Thank you!
But what tool do you recommend to cut back flush?
I made a new comment with photos at the end of this thread but thought Ièd ask you directly as well!
Joe's idea will work fine provided that a significant amount of rot doesn't extend into the interior of the building. This is why extending joists from inside to outside is not such a great idea.
-- J.S.
Thanks for the suggestions.I like the ledger idea quite a bit except I am constrained by an esthetic issue in that the the house is two stories and the deck/floor/ceiling joists are midway. I would like to hide all of my deck joist splicing and sistering behind the siding and ceiling drywall. I used to know the rule of thumb for this but I forgot so can someone please remind me: how far does new joist have to overlap the existing joist when sistering? I remember something like "it has to go one third the length of the new joist."
I seem to remember that it's so many times the width of the boards, but don't remember how many times. Someone else will come up with the answer, I'm sure.
Edited 8/9/2005 7:24 am ET by Danno
I used to know the rule of thumb for this but I forgot so can someone please remind me: how far does new joist have to overlap the existing joist when sistering? I remember something like "it has to go one third the length of the new joist."
You don't need know rule of thumb and go in and overlap the deck joists for your situation because of the outside header with the colulms. If you don't want to see the ledger then just sit your joists with full bearing on the top plate of the house and be doine with it.
The only reason why you sister joists and come in is because the cantilevered joist have nothing to hold them up on the end but you do with that header and columns so you don't have to go in any amount, just sit them on the top plate and make sure you flash it properly.
Thanks for all your input on this- it has helped me quite a bit. I still would like ot know that rule of thumb even if it is not applicable in this situation.T
The rule is 2 to 1. A four foot cataliver needs 8 feet buried in the joists. This is minimal and I would do more to sistered joists. Also check with the city to see what their take is on this.
Hey, We are in a similar situation.
I plan on doing Nic recommendation above. The question is what tool do you use to cut back the deck joist nearly flush?
Look at the hole from bee borings
“[Deleted]”
Hey Melde,
We are currently in the same situation. Did you find a way to cut the floor joists back 2" ~, so the band joist would sit flush with the house? Also how did you secure the band Joist and did you add blocking behind it?
Thank you,
Ryeman11