I have a situation where a concrete approach to an attached garage traverses a slope and is about 3′ off the ground on one side. It has a monopour foundation wall under it over who knows what kind of footing. To the point, original builder attached a cedar ledger for a cedar deck directly to that concrete. Of course, all the runoff from the drive runs directly onto the ledger. It has dropped about 1.5″. Inspection reveals a ring of rot around each badly corroded bolt. They want to save the deck for another few years. This rotted ledger is all that holds the 12′ (from concrete out) deck from falling away from the drive.
JLC 8/03 has an article on attaching decks. Detail 3a presents the most appropriate fastening technique, I think. It suggests using 1/2″ stacks of washers between the ledger and the fastening surface for spacers. The sticker is that I’ve got to somehow locate the washers between a new ledger and the concrete and then thread a wedge anchor through them. On top of that, 3.2″ o.c. spacing is recommended for fasteners! An alternative is to tapcon joist hangers directly to the concrete and eliminate the ledger altogether. The flip side to that is that the joists are shy of the concrete by the thickness of the existing ledger.
Any suggestions?
Replies
I would Jack the deck back up the 1 1/2" and run a 4x8 beam along side of the wall with 4x4 posts every 6' down to the foundation footing as a Band-Aid fix. It would be nearly impossible to remove and replace the ledger with the deck attached.
Here is a stand off bracket you might run past your building department, but it would be a costly fix. http://www.DeckBracket.com The great thing about this system is that the bracket would allow you to cut all the joists and re-attach a treated ledger.
They want to save the deck for another few years
If the ledger is cedar what are the joists made of? I would guess they are not pressure treated.
The trouble with getting involved with a project like this is that the customer does not want to spend the money to fix it right.
Ask your customer how long they plan to live in their house. I would try to explain to your customer that the cost of repair comes close to the cost of replacement and that replacement would last more than a few years. If it is unsafe now it will have to be replaced before they can sell their house anyway.
"Rather be a hammer than a nail"
Bob
You said: "They want to save the deck for another few years"
To add to what Pro said, what is the sense in installing a 25 year fix on a deck with a 10 year (max) life span? Pro's is the correct solution, (free standing deck) but is it worth it? Same goes for the washer spacers solution shown in the drawing you attached. Even if you do the free standing deck, you are still gonna need to attach the deck to the concrete just to hold it tight against the concrete.
Not sure what your arrangement is but I'd bill them time and materials. It's gonna be a PITA... Either that, or don't take the job - unless they have already committed to giving you other more lucrative projects. They sound like penny pinchers. Think about it while you are under that unstable 2500# deck, jacking it back in place.
Edited 9/12/2003 7:37:38 AM ET by DIRISHINME
Pro and DIRISHINME,
Thanks both for your replies. I accept and agree with your views. This is a common situation in remodeling -- how much to rip out and repair vs rip it all out and start over.
To be fair to the HOs, I think their implied question to me is "Is there a 5 year fix for this deck?" I think they want to replace it but maybe can't swing it at this time. But we haven't discussed that far and are undoubtedly open to my suggestions.
I think the labor to excavate and set posts and beams under the joists near the ledger would be expensive and, yes, a PITA, because the deck at this point has 2' of clearance above ground. I'd have to remove 3' of decking to work in there. Added to that, which I didn't tell you in the original post, the outside of the deck (25') is supported by 3 4x4s cedar whose bottom ends are slowly disappearing. Further, the bottom stair landing is performing similarly. The labor to repair this would be best applied to a new deck.
I'll recommend removing this structure and applying repair labor to a new structure.
BTW, my experience has shown me that cedar is pretty much useless for applications where water sits on it. Am I being unfair to the material?
Cedar is not structural nor intended to be near standing water. Your deck sounds like it would be a good place for Trex or some other composite decking. All the framing should be incised pressure treated doug/fir.
Of all the woods cedar will withstand the moisture, drying, expansion, and contraction better than Pine, fir, hemlock, redwood,mahogany, or ironwood because it is more porous. It is however, weaker structurally because of that."Rather be a hammer than a nail"
Bob
yes, thank you.
If/When I rebuild the deck, what do you think about eliminating a ledger altogether and fastening joist hangers directly to the concrete?
I like those Maine ledger brackets. I've contacted them regarding dimensional specs. thanks.
Joist hangers were not designed or meant to be attached directly to concrete. Just install an incised pressure treated ledger with striker bolts, then attach your hangers to that."Rather be a hammer than a nail"
Bob
What do you mean by "incised"?
Incised are the staple looking insisions that allow the pressure treatment to penetrate the wood. It looks like this."Rather be a hammer than a nail"
Bob
Pro:
Just as an FYI, in the southeast, our PT lumber is SYP (Souther Yellow Pine) and it doesn't come incised. Now I know the term though. Thanks.
Tim:
Just get some 1/2" or 5/8" red heads at least 6" long and bolt a new PT ledger every 6". http://www.ramset-redhead.com/trubolt.asp And don't tell anyone I told you so ;^) Forget the spacer washers - yours is only a 10 year (max) installation and since the ledger is above grade, it will only intermittently be wet.
All:
The central issue here, In my opinion, is that decks must be either through-bolted to the structure (bolt, nut, washers) or built as a free standing deck (a post at least on all 4 corners and diagonal bracing in both directions). I know that a lot of you all use lag screws, and screws are often sufficient, but they are not permitted under our NC code, and IMO incidents like the recent Chicago deck collapse disaster would be nearly non-existent if the all decks were either through-bolted or free standing. In NC, they toughened up the code after having several decks collapse. The through bolts are only adding roughly $30 to the project cost and, at that rate are cheap insurance. BTW - from the pics, again, IMO, ledger attachment was not the only gross deficiency in the Chicago issue. For example, it also looked like the outboard "beams" (girders) were a single 2x and it was only nailed to the side of the posts - not through bolted.
Just my opinion
Matt
Edited 9/12/2003 4:54:33 PM ET by DIRISHINME
Like Irish Matt says, we here (midwest) have SYP for PT lumber -- no incising (or incisions, or whatever it is).
BUt, to both of you, what I want to do here is, in the event I get to rebuild the deck, avoid a water trap between ledger and concrete. I don't have the option of using wall flashing, as there is no wall. I'll take a closer look at the brackets you recommended. Seems like they stick out quite a bit from the mounting surface, though. One would have to engineer a suitable method to mount the first row of decking over those brackets.
A free standing deck is possible here, but fastening to the concrete would, obviously, save the expense of excavation and posts along the structure.
Matt, I appreciate your comments about safe deck construction.
BTW, what is "IMO"?
IMO in my opinion "Rather be a hammer than a nail"
Bob
Yes, thank you. Much better to express things "IMO", than dogmatically as is sometimes the case here on the forum.