Deck: how to attach stringers
Total klutz here, fixing my deck stairs.
There is a landing, and then 3 steps up to the main deck. Im replacing the last bit, from landing to deck.
The top step is down, not level with the main deck. So there are three sets of treads but four rises. Total rise is 29 ¼ from tread-surface of landing to that of the deck. Total run is about 30. The stairs are about 4 wide.
The existing construction is flimsy. Everything is pressure treated, and the stringers were made out of 2 x 12, which is good. But the deck uses 2x6 joists; the rim joist is not doubled. The stringers do not reach the rim joist at all; their tops are about ¼ inch below the bottom of it. The guy nailed up three two-foot vertical 1 x 3s to the inside of the rim joist (the side toward the deck, not the stairs) so they project down a foot or so, and then attached the stringers to those. Is this as laughable as it looks to me?
So what to do? Should I put in a hanger board? I imagine using 2 x 12, across the width of the stairs. This would project down about 4 below the rim joist, which is enough for the stringers to attach to. I would put the hanger board on the inside of the rim joist, where the silly sticks are now. Does that sound solid?
How do I attach the hanger board to the joist? How do I attach the stringers to the hangar board? (I assume I just nail/screw through the hanger board from the backside into the end of the stringer? What should I use for nails/screws?)
If there are relevant existing threads, point me to em. The ones I found about how to attach stringers seemed to assume indoor use.
Thanks in advance,
I don't know about laughable, but interesting. Any pics? Drawings?
Hi JKlingel, here's a view from underneath the
stairs of the way the stringers attach to the "silly sticks"
Sorry about the false color -- result of compressing it
down to the allowed file size. In my browser (google
chrome) it shows way-too-zoomed-in, and you need
first to zoom out a bit with control-mouse-wheel to see
the whole pic.
That is pretty amusing. You attach the stringers to the hanger board using stair stringer brackets, which are adjustable galvanized brackets made by Simpson or competitor, specifically designed to attach stringers to a hanger board. Typically the brackets take 10d galvanized nails. You need to make sure the hanger board is very solid. Usually it is attached to the deck posts, which may not be possible in your case. If you have no posts or other solid vertical framing to attach to, you may be able to use Simpson or equivalent framing brackets to attach to existing framing, but is it hard to know exactly what framing to attach to and what connectors to use without being there.
But a 10d nail is 3" long, and would pass right through the hanger board and through the stringer (2" thick) too, except the one nail that goes into the endgrain of the stringer. ??
There are examples where the stringer is extended under the deck so it eventually connects to the second joist. That could be done here, but it still doesn't provide any vertical support.
That looks like a creative solution to an IF'dU deal. Any way to put the bottom of the stairs on a concrete or PT wood frame to raise them, and hang the stair stringers onto one of those 2x10s? I'd also likely put some kind of post(s) under them, just for stink and giggles.
Well, in the end I didn't go with the hanger board. I cut the stringer longer, so there was a "step" extending up under the deck between the rim joist and the next one. Then I secured it as best I could. See attached photo.
Only about 2" of it reached the second joist, however, so to use a joist hanger there, I tacked on a triangular bit. I think this is fine for purely vertical support. It cannot move forward/back since it is trapped between the two joists and fits pretty flush. But it could conceivably move sideways, sliding off the triangular bit, so I used some twisty-thing hangers inside the rim joist to hold it in that dimension as well. The only thing I didn't use was duct tape.
Now the remaining concern I have is that the critical dimension on a stringer is the distance between the deepest cut and the opposite side of the board, which, I have read, is supposed to be at least 5 1/2 ". The rest of my steps are fine, but it only about 4" on the last step up under the deck, the one in the photo, because that step is deeper (because it has to reach under the rim joist before rising again).
So are there any further reinforcements that can be applied to strengthen that weak spot?
I have the same problem on some other stairs, where I was not replacing the old stringers. They are longer (8 or 9 steps) and only about 4" at the critical dimension. So I might reinforce them similarly.
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