Cantilever Deck Problems - Rotten Wood

[David Helm]

If you go the "sister" route bear in mind that the sisters have to go from bearing point to bearing point. Otherwise the only support for the sister will be the nails to the other joist. Not adequate support and does not meet code if not bearing point to bearing point.

[Charlie Velasquez]

If you go the "sister" route bear in mind that the sisters have to go from bearing point to bearing point. Otherwise the only support for the sister will be the nails to the other joist. Not adequate support and does not meet code if not bearing point to bearing point.

Wouldn't all the force on the interior part of the sisters be going upwards?
I don't know the condition of the interior part of the current joists wrt supporting the actual house structure. If they are affected it may entail temporary support and replacing the entire joists system. As mentioned, a structural engineer should be consulted. It looks to present enough problems that safety should not be compromised to save money. It may cost a lot more in the end.

[Al Launier]

Wouldn't all the force on the interior part of the sisters be going upwards?
I don't know the condition of the interior part of the current joists wrt supporting the actual house structure. If they are affected it may entail temporary support and replacing the entire joists system. As mentioned, a structural engineer should be consulted. It looks to present enough problems that safety should not be compromised to save money. It may cost a lot more in the end.

Typically the "moment" forces from weight on the cantilevered portion would want to raise the joists inside the house, but the more significant weight of the floor above this counteracts.
If the joists within the house are rotted, or headed that way, then you are correct in that the entire system needs to be addressed by a professional qualified in home construction, typically an engineer.

However, the pictures don't really show the condition of the interior joists. They have to be "probed" to determine this in addition to visual appearance.

[Stephen Tashiro]

To me, the terminology 'sistering" would apply if the original joists were left in place and other boards were attached to their sides. What Mark describes in his original post apparently involves removing the ends of the joists and "splicing" new ends onto the joists by attaching the new ends to the old joist and a third board..

Can somene comment on how hard it is to remove the end of a floor joist from under an existing floor? When the new joist is put in place, how is the subfloor attached to the new joist - by brackets?

[Lee Schierer]

After looking at your photos;

1. You can't attach a ledger board because you don't have a rim joist inside the building in that area.
2. Free standing decks that high off the ground are generally not allowed by code.
3. Your existing joists have water damage that comes inside the house based on the water stains in your photos on the wood and the insulation. Your floor and outside stud wall may not be properly supported depending on the extent of the rot to the joists and the sill.
4. Sistering will require more than 6 feet inside the building to support a cantilevered deck.
5. Removing one floor joist at a time is going to be a ton of work, and your sill could also be rotted. Your entire floor will become free floating unless you put in screws from above.

It would appear that your only recourse is to remove the deck and install new joists that run to the main beam inside the house. This will buy you maybe 15years, possibly more before you have the same problem again, because even with treated lumber, you will not be able to permanently seal the wood penetration through the outside wall of the house.

[roger wiegand]

If you don't like posts out in the drive (perhaps not my greatest idea, but I'd do it before the cantilever option), you could fabricate a steel support -- sink a vertical beam into a hefty foundation at the ends and middle close to the house with a braced horizontal member to hold up the deck. You'd need an engineer to spec it out. I've had two houses where I needed to deal with rot reaching well back into the house as a result of the cantilever design and lousy flashing; repair was a major PITA. Hence my aversion to that method.

[Mark W Pugh]

After looking at your photos;

1. You can't attach a ledger board because you don't have a rim joist inside the building in that area.
2. Free standing decks that high off the ground are generally not allowed by code.
3. Your existing joists have water damage that comes inside the house based on the water stains in your photos on the wood and the insulation. Your floor and outside stud wall may not be properly supported depending on the extent of the rot to the joists and the sill.
4. Sistering will require more than 6 feet inside the building to support a cantilevered deck.
5. Removing one floor joist at a time is going to be a ton of work, and your sill could also be rotted. Your entire floor will become free floating unless you put in screws from above.

It would appear that your only recourse is to remove the deck and install new joists that run to the main beam inside the house. This will buy you maybe 15years, possibly more before you have the same problem again, because even with treated lumber, you will not be able to permanently seal the wood penetration through the outside wall of the house.

The photo that shows water damage is the only joist that has that kind of rot. All other joists just have rot on the exterior portion. I would screw the floor down to the new joists from the rooms above.

I will add, the water damage was due to leakage around the door, and not coming in from the joist. This all happened before I moved in, 2000. There is separation between the brick veneer and the block foundation.

A lot to think about here.

[matteo furbacchione]

What you have there can be redone exactly as it is now, no question. It would be technically easy but be very time consuming and a hell of a wrestling match... And I'm sure you are aware you'll probably have to do it yourself as no licensed carpenters would want to take on the risk and liability...

The way I see it is you'll have to rip off the rim/header/trimmer joist and railings. Rip all the insulation and what not down from inside to expose all of the joists all the way back to the beam or bearing wall. Rip up the carpet upstairs to expose the floor back to the beam or bearing wall. Don't forget you'll probably have wiring and plumbing to contend with. Which means you'll have to get them rerouted as this is a project that will take some time... Then start cutting each affected joist out individually and sliding in a new one before moving to the next. That would entail running a sawzall between the joist and the flooring to cut the nails/screws with a metal blade. Doing them one at a time should eliminate possible sagging issues. Then you'll need some sort of frame set up to hold up the new joist while you slide it in, then nail/screw the floor down to it. Don't forget a vapour barrier between the new wood and brick.

To compensate for shrinkage in new wood you'll need to factor in shimming the new material up as it shrinks. Not difficult, just have to be diligent in watching it and acting on it. You won't be able to seal up the building to any degree (which will never be 100%) until the the movement has stopped.

Don't cheap out and use non-treated wood, not unless you want to do it all over again sooner rather than later.

Easy Peasy!

Is it the right way to do it - absolutely not. But I'm not the one footing the bill so you have to determine what you can afford and sleep with.

And as is the case your mileage may vary.

[Mark W Pugh]

What you have there can be redone exactly as it is now, no question. It would be technically easy but be very time consuming and a hell of a wrestling match... And I'm sure you are aware you'll probably have to do it yourself as no licensed carpenters would want to take on the risk and liability...

The way I see it is you'll have to rip off the rim/header/trimmer joist and railings. Rip all the insulation and what not down from inside to expose all of the joists all the way back to the beam or bearing wall. Rip up the carpet upstairs to expose the floor back to the beam or bearing wall. Don't forget you'll probably have wiring and plumbing to contend with. Which means you'll have to get them rerouted as this is a project that will take some time... Then start cutting each affected joist out individually and sliding in a new one before moving to the next. That would entail running a sawzall between the joist and the flooring to cut the nails/screws with a metal blade. Doing them one at a time should eliminate possible sagging issues. Then you'll need some sort of frame set up to hold up the new joist while you slide it in, then nail/screw the floor down to it. Don't forget a vapour barrier between the new wood and brick.

To compensate for shrinkage in new wood you'll need to factor in shimming the new material up as it shrinks. Not difficult, just have to be diligent in watching it and acting on it. You won't be able to seal up the building to any degree (which will never be 100%) until the the movement has stopped.

Don't cheap out and use non-treated wood, not unless you want to do it all over again sooner rather than later.

Easy Peasy!

Is it the right way to do it - absolutely not. But I'm not the one footing the bill so you have to determine what you can afford and sleep with.

And as is the case your mileage may vary.

So, there is not that much to move, electrical/water/other. And access from the floor above is not a problem. The carpet has to come up anyway.

The real question, do I need to replace the joist all the way back to to perpendicular joist? I would like to cut off the joist about 6' foot inside. Bring the new joist in, butt the two together, and sister together with a 6' board on each side of the butt joint. I would use adhesive and bolts. Then screw to flooring above. Where the new joist exits the house, attach new joist to wall base plate, and the plate on supporting block.

I guess I need a structural engineer/architect see if this is code/afe.

[matteo furbacchione]

Unless I was going to redo the whole deck and floor right I wouldn't do any "slight" changes to how it was built. Just incase there were liabilities incurred down the road. An engineer is an option but I would be surprised if they would sign off on such modifications. YMMV

[Jerome Sidley]

Cantilevered decks are a bad idea. I was involved with a couple 30 years ago and both developed serious problems. They leak and invite bugs into the house.

My advice is to cut off the cantilever, seal the house, and if you want a deck there, build it independently from the house, supported on both ends.

This is good advice!

[Osvaldo Cristo]

No personal experience but I reminded casually I had read about that recently: http://www.deckmagazine.com/design-c...he-2015-code_o

I hope that can help you.

All the best.