# Hanger board for stair stringers



## Millertyme (Apr 20, 2010)

Will there be walls in either side going up the stair?


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## AlphaPilot (Aug 6, 2012)

Left side yes. Right side has rim board and I joist sistered to support the floor with a double 2x4 to catch that point load.


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## Yodaman (Mar 9, 2015)

I did this for my basement stairs. Exactly for the same reason. I used 2 ply of 3/4 plywood. It drops down 7 or 8 inches from the 8" header that it is attached to.

Not sure about code compliance, but my inspector did not question it.


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## keymaster (Jul 28, 2015)

Do you happen to have any photos of this?


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## Yodaman (Mar 9, 2015)

keymaster said:


> Do you happen to have any photos of this?



I do not have any from the construction, and not a whole lot to see now but here is couple that I just took. These stairs lead to a unfinished basement that comprises mostly of my shop and a mechanical room.

The first is from behind the stairs, you can see the drop in the ply.
The second is from the side shows the 2 layers and a treated stringer attached to it. I covered the stringer with 1 x #2 mat'l,
The third pic shoes the 2 layers plus the finish layer that makes up the finish riser board.
4th is just a wider shot from side.


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## AlphaPilot (Aug 6, 2012)

Pics look similar to my idea...though not all the stringer will be lower than the header.

I am planning only one piece of plywood....3/4 thick and half of the stringer will be into plywood and 2x12 while the lower half is gonna be only in the plywood. I think if I use const. adhesive on the plywood against the 2x12 it will become one piece in terms of tear out. The plywood will also serve as my very top step's riser board. I will have my subfloorinf cut back to imitate the nosing edge on all of my stairs. Now...just if I can figure out if I want to mount stringers to plywood then hang it or hang each stringer individually.


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## Yodaman (Mar 9, 2015)

I am not 100% sure how I did this set, but I think I lagged up the first ply, then lagged the second ply to the 3 stringers, and then nailed and screwed the 2 together. If you look at pic 1, you can see swirl marks where I used a right angle grinder and cut off fasteners that went thru.


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## Yodaman (Mar 9, 2015)

A couple pics of the front side. The stair treads are 1" thick pine from HD. Very reasonable as I recall and much easier then making them your self. Risers cut from plywood. The carpeted step pads were from a Grossmans outlet.


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## keymaster (Jul 28, 2015)

Yodaman said:


> I did this for my basement stairs. Exactly for the same reason. I used 2 ply of 3/4 plywood. It drops down 7 or 8 inches from the 8" header that it is attached to.
> 
> Not sure about code compliance, but my inspector did not question it.



Yoda, regarding stringer bearing on a joist, I couldn't find a specific reference. It is a common problem in stair construction. It may fall under best practices rather than a code requirement. If the stringer is designed so that the top tread is equal to the floor, the stringer will have full bearing. The problem happens when you design the joist to be the last riser. 

Regarding stairs IRC says:



> *R311.5.1 Attachment. *
> 
> Exterior landings, decks, balconies, stairs and similar facilities shall be positively anchored to the primary structure to resist both vertical and lateral forces or shall be designed to be self-supporting. Attachment shall not be accomplished by use of toenails or nails subject to withdrawal.


Your solution looks solid. (That said, two sheets of plywood don't have the rigidity of a double 2x header.) Some inspectors might have a problem with the percentage of the stringer bearing on the header, much like percentage of joist to the size of a ledger. 

I think the issue comes from the geometry that results when you cut a 2x12 with the intent of making that top cut a tread other than the first/last. Part of it depends on the height of the riser--a short riser and this isn't a problem with 2x12 joists.


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## keymaster (Jul 28, 2015)

Yodaman said:


> A couple pics of the front side


Looks nice.


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## Yodaman (Mar 9, 2015)

Don't recall why I made them this way, unless it was the space constraint. 
I remember the rise run was customized also to help accommodate the space. The landing at the bottom I think is at the min.
This stair was the practice set for the oak set that went in upstairs!


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## keymaster (Jul 28, 2015)

AlphaPilot said:


> Pics look similar to my idea...though not all the stringer will be lower than the header.
> 
> I am planning only one piece of plywood....3/4 thick and half of the stringer will be into plywood and 2x12 while the lower half is gonna be only in the plywood. I think if I use const. adhesive on the plywood against the 2x12 it will become one piece in terms of tear out. The plywood will also serve as my very top step's riser board. I will have my subfloorinf cut back to imitate the nosing edge on all of my stairs. Now...just if I can figure out if I want to mount stringers to plywood then hang it or hang each stringer individually.


Regarding adhesive and plywood: it's not enough on its own, you need backer blocks on both sides. (Without seeing the framing plan, I can't be certain of the need for hangers, but I prefer them.) You need more than a single sheet of plywood to support a portion of the stringer, and possibly backer blocks, and fillers. Is a permit involved?

Generally speaking, use filler blocks at the webbing between double I-joists (headers for example) and backer blocks on _both sides_ of single I-joist webbing when connecting hangers. Use an approved I-joist hanger to connect to the joist chord, not just the webbing. There are I-joist specific hangers. 

Simpson illustrations of specific hangers and installation methods:
http://lpcorp.com/media/3307/simpson_strong-tie_hangers.pdf

Illustration of backer blocks and filler blocks, and how hangers are installed with each. (I don't know the source, so I can't vouch for the nailing patterns.)












This is probably not directly related to the question, but the code regarding floor framing might help:

The IRC only requires a double header if more than 4' span, double trimmers if greater than 3' from bearing, hangers at the header if greater than 6' span.

Personally, I don't think the code is enough here. I prefer to see double joist headers regardless of opening size at a stair. I would always use (approved) hangers at stair headers, and stair framing in general.


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## AlphaPilot (Aug 6, 2012)

I have a 2x12 used as my header. It is fastened to one 2x12 running parralel to my stairs, as if it were an I-joist, just that it's a 2x12 and has a support wall under it the whole length. The other side I have an I joist with a rim board attached to it for a nice flat surface. The rim board and I joist rest on the main middle house beam further back before the stair cut out. On the other end they rest on 2 LVLs with a double 2x4 as a support post. I have two 2x12 joist hangers by simpson used to hold the 2x12 header. Those hangers are screwed into the two sides I just described, I used the simpson #10 screws specified for their hangers. After that, I then glued, screwed, and nailed a piece of 3/4" plywood to the 2x12 header to extend a few more inches down past the 2x12 header which would otherwise not have been able to catch the bottom edge of the stringer start. I used 2 ceramic screws and 2 ring shank nails per stringer fastened from the back side of the 3/4 plywood into the stringer before I lifted and installed the plywood with stringers into the 2x12 header. Clear as mud? lain:

If this does not sound pleasing, or if I find it does not feel 100% solid, My plan would be to build a 2x4 wall to support the 2x12 header that is hung with hangers into the sides.

General question here, besides getting an answer like 'leave it to a pro' - what is the standard method of fastening stringers into your header if you *do* have access to the back side like I did? How many nails per typical stringer? Or is it only screws? That's why I used two of each. Screws worry me with shear strength but nails worry me for eventually working loose or causing the material to squeak as it expand/contract around the metal.

My only concern I have is that method the stringer is attached to the plywood. I am fairly confident the 2x12 will carry load and am sure I can beef it up more if required. I just wonder how strong 4 fasteners can be into a simple nominal 1.5" x 6" piece of meat (the 2x12 stringer board after being cut) I don't know about carrying a piano down the stairs for example. I will be carrying any heavy items through the walkout basement door for that matter. I do want to make sure it can support plenty of live load from people.
Edit: Stairs are 42" wide - 3 stringers - 2x12 tread material and 1x8 riser material.


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## Gary in WA (Mar 11, 2009)

Ask your local Inspector about the plywood design before you hang it... it may need to meet the 600+# vertical shear load usually met by a sloped hanger- unless you have side walls, *Fig. 31*; http://www.awc.org/pdf/codes-standards/publications/dca/AWC-DCA62012-DeckGuide-1405.pdf Ask them if the floor 2x in the last step bolted to slab helps resisting kick-out for using plywood only. eg; Simpson; http://www.strongtie.com/products/connectors/lsc.asp

Gary


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## AlphaPilot (Aug 6, 2012)

Gary, I did not end up using any angled stringer fastener. It's just plywood into the stringer.

I was going to notch out room for a 2x4 at bottom of stringers to resist it from slipping out but decided that may weaken it more than help it (since bottom step is always the shortest one to accommodate tread thickness board). I have it toe screwed and nailed into my landing, but was also going to install blocking between the stringers face nailed to the landing to attach the bottom sides of stringers against to try and make up for no notch and kickout support board. Local building store said it is 'common' to use the plywood and also 'not common' to use the angled stringer hangers that I originally was going to use in place of the plywood. :vs_worry:


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## Yodaman (Mar 9, 2015)

Alpha, I am most concerned about how the stringer is attached to the ply. Two ring shank nails. What size? And one ceramic screw? Was the screw a structural screw or a deck screw? Deck screws are not allowed in shear applications which you hinted at.

I would find a way to beef up that connection.


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## AlphaPilot (Aug 6, 2012)

They are 3.5" ring shanks and 4" ceramic torx. I used two of each per stringer. I don't know how you could get any more fasteners in there without splitting. 4 fasteners was one every inch. I am thinking of using metal 90 brackets to screw in the side of the stringer and then into the ply. Those also would risk splitting.


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## keymaster (Jul 28, 2015)

AlphaPilot said:


> I have a 2x12 used as my header. It is fastened to one 2x12 running parralel to my stairs, as if it were an I-joist, just that it's a 2x12 and has a support wall under it the whole length. The other side I have an I joist with a rim board attached to it for a nice flat surface. The rim board and I joist rest on the main middle house beam further back before the stair cut out. On the other end they rest on 2 LVLs with a double 2x4 as a support post. I have two 2x12 joist hangers by simpson used to hold the 2x12 header. Those hangers are screwed into the two sides I just described, I used the simpson #10 screws specified for their hangers. After that, I then glued, screwed, and nailed a piece of 3/4" plywood to the 2x12 header to extend a few more inches down past the 2x12 header which would otherwise not have been able to catch the bottom edge of the stringer start. I used 2 ceramic screws and 2 ring shank nails per stringer fastened from the back side of the 3/4 plywood into the stringer before I lifted and installed the plywood with stringers into the 2x12 header. Clear as mud? lain:
> 
> If this does not sound pleasing, or if I find it does not feel 100% solid, My plan would be to build a 2x4 wall to support the 2x12 header that is hung with hangers into the sides.
> 
> ...



As I said, I don't like the stringer into single sheet of plywood method. If you use a dropped stringer, you should be using an approved hanger--or whatever the code and building dept wants. Nails into plywood have different characteristics than into dimensional lumber. Generally, they pullout much more easily. 

The easiest way to make sure your assembly is going to meet "engineered" standards is to use engineered hangers and follow manufacturer's nailing schedule. If you were to use this hanger, a Simpson LSCZ for example, and the approved nails/fasteners, then Simpson tells you what to expect in terms of strength with load tables.

http://www.strongtie.com/products/connectors/LSC.asp

I don't think you need a wall, but I can't say for certain without photos. (I did follow most of your description, surprisingly, but that's always different than seeing it.) I do think you should use hangers if your intent is to drop the stringer, and get a permit.


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## Gary in WA (Mar 11, 2009)

Ask the local AHJ... I built over 300 sets (many double sets) of stairs all using plywood for the top riser and all passed code. Granted, this was from '74-'04 and the stringers all were face nailed to sidewall studs AND all had kicker at bottom. This alone makes the stringer angled so loads are mostly on bottom heel cut, not *vertical* fastener or *resistance-to-withdraw* loading as much. Tell us what they approve of...

Gary
PS add a flat 2x across the stair hole at bottom ply hanging height for a nailer. Fasten through both into stringer from backside, if worried.


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## AlphaPilot (Aug 6, 2012)

Gary, what did you use back in those days to fasten the plywood riser into the stringer?

Also, are you saying use a 2x4 under the stringers to create a ledge and fasten it into the plywood, or ? I cut the plywood extra long past the stringers so I could fasten supports into it if needed. I was considering a 'ledge' under the stringers but it would only be as strong as the fasteners in the ply.


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## keymaster (Jul 28, 2015)

One comment unrelated to the stair stringer issue: I don't see much at the I-joist to header connection except possibly adhesive. Is the wall near it bearing the joists? Perhaps you do need a wall under that connection to stabilize it. (In the future, use hangers.) 

The plywood looks to be deforming under stress. One possibility is to get blocking (dimensional) between the stringers, toenailed and endnailed into the stringers, and then fastened into the header. Use structural fasteners. It's not ideal, but I can't think of what is at this point. The plywood isn't helping--it can't be the basis for supporting anything.

(Ask the building department.)


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## AlphaPilot (Aug 6, 2012)

Getting it looked at today. The I joists are not there for load. I used glue to close the gap but decided I shouldn't fasten the 2x into the I joist flanges. They have a support beam 16" away from them. They are okay. The plywood looks bowed because the Simpson screws bulge out from the 2x header.


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## AlphaPilot (Aug 6, 2012)

Inspector had no problem but suggested either screwing the side stringers into the future wall or using joist hangers to grab into the plywood more.


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## keymaster (Jul 28, 2015)

AlphaPilot said:


> Inspector had no problem but suggested either *screwing the side stringers into the future wall *or using joist hangers to grab into the plywood more.


Do that. Connect the stringer into the framing beyond that is visible in the photo. If there is any gap, block it solid and connect through the blocking to prevent it from twisting. (Structural fasteners or toenails.) If there is to be a wall on the near side of the photo, connect to that in the same way. 

I'm not sure how joist hangers would work there. I think you might have better luck with hurricane straps under the bottom edge of the stringer, tied to the face of the plywood and into the header. 

Something like this, flip it over in your mind:


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## AlphaPilot (Aug 6, 2012)

We thought Simpson made an angled one for this application. If not, they suggested a standard joist hanger just high up enough it would be carrying some load if it settled any.

Being since I have to have railing on the open side, and that is apparently extremely expensive, I think I will just build a wall and enclose it? Right now I am battling how I can secure a half high wall upstairs to surround the stairs instead of expensive (but nice looking) balasts. I can easily frame a wall around it, but I know someone will lean into it and it would have no top support. Is it common to go to the ceiling to get support? That seems the most practical without attaching along the staircase opening with 4 x 4 posts similar to how decks support their exterior railing. I just can't afford to do a nice open railing around the stairs at this stage. I would plan on that after years pass. So right now I am thinking of having 3 double 2 x 4 posts to connect to the ceiling and then fasten into the floor and then anchor my 4' high wall to those for support. The cheaper or more efficient the better, just as long as its strong!


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## Yodaman (Mar 9, 2015)

AlphaPilot said:


> We thought Simpson made an angled one for this application. If not, they suggested a standard joist hanger just high up enough it would be carrying some load if it settled any.


I have used std joist hangers in the past on deck stair stringers. But I always cut a notch on the under side of the stringer to sit on the hanger shelf.





AlphaPilot said:


> Being since I have to have railing on the open side, and that is apparently extremely expensive, I think I will just build a wall and enclose it? Right now I am battling how I can secure a half high wall upstairs to surround the stairs instead of expensive (but nice looking) balasts. I can easily frame a wall around it, but I know someone will lean into it and it would have no top support. Is it common to go to the ceiling to get support? That seems the most practical without attaching along the staircase opening with 4 x 4 posts similar to how decks support their exterior railing. I just can't afford to do a nice open railing around the stairs at this stage. I would plan on that after years pass. So right now I am thinking of having 3 double 2 x 4 posts to connect to the ceiling and then fasten into the floor and then anchor my 4' high wall to those for support. The cheaper or more efficient the better, just as long as its strong!



It is possible to build a solid 1/2 wall just like it is possible to set a newel post solid. Prebuild the wall using structural adhesive and screws. You should have a double 2 x beam right under the proposed wall location that supports your stair way opening. Lag your wall to it. 
Also if you have a surface planer, removing enough mat'l to get past the corner radius will increase bearing area by 15% on a 2 x 4. Just as important, skimming all the faces of the upper and lower plates will eliminate any crown in the boards, which could cause wobble
Or using 2 x 6 width mat'l would be even better.
Be sure to clean cut all your wall studs square.


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## AlphaPilot (Aug 6, 2012)

I could notch, but that'd make the stringer that much thinner. I found one hurricane tie that is angled but not sure it's the right angle i need. 

When you say lag, you mean ledgerboard screws or literal bolts? I'd like to make it temporary enough for when I change to open ballast system 3-5 years from now. 

When you say corner radius, you mean to make every stud perfect square, or something else? I need to buy a hand planer I think.


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## Yodaman (Mar 9, 2015)

AlphaPilot said:


> When you say lag, you mean ledgerboard screws or literal bolts?
> .



Yes a heavy screw. Like 5/16 x 5" or ledger screws would work well also.
A bolt uses a nut which would not work for you, unless you want to use anchor studs with a screw thread on one end and machine thread on the other. But really serves no advantage over the lag screw.
[/QUOTE]



AlphaPilot said:


> When you say corner radius, you mean to make every stud perfect square, or something else? I need to buy a hand planer I think.


Regarding radius, I was referring to the lower plate that the wall studs set on. A 2 x 4 measures measures 3 1/2" wide. The factory edges have approx 1/4" radius on all 4 corners. If you subtract the radius you are down to only 3" of the plate actually touching the floor. By running the boards thru a thickness planer you can eliminate the radius and have the full 3 1/2. This is not a hand plane job.

No surface planer? Plane B, buy a 2 x 6 width board and rip both edges to make your own 2 x 4 with out a rad.

Lumber often will have a crown in it. When you have a crown on the lower plate board it will help to loosen the wall and allow it move. You need to eliminate the crown on that bottom board. This could be done with a hand plane. Or a belt sander. Just get it as flat as you can

Awhile back someone started a post looking for ideas on how to stiffen a loose short wall. If you can find it, might have some ideas for you.


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## keymaster (Jul 28, 2015)

AlphaPilot said:


> We thought Simpson made an angled one for this application. If not, they suggested a standard joist hanger just high up enough it would be carrying some load if it settled any.


They do, especially for rafters, but they won't match your pitch and if you get the adjustable kind they have to sit between the stringer and the ledger/header, and that's not possible here. That's why I like a strap, you only need access to one side of the stringer. With a joist hanger you need to secure both flanges for it to be doing anything. Do you have room for that?--it doesn't look like it to me. On the center one you do, but not the ends.

A strap can be tensioned, a hanger can't. If a hanger won't fit, use a strap. Fasten to the header first, wrap under and around and then fasten with screws up into the stringer, which will tighten it. Then once it has tightened, put additional fasteners into the strap to attach to stringer. 

The choice of a railing or a wall is preference, either will work. Posts can be fastened using special plates for attachment on the stair (such as newel posts), or into the side of the opening itself, for a guardrail.


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## AlphaPilot (Aug 6, 2012)

The wall I have on the left is a full wall - no problem. The wall on the right is the half high wall I will have for now. I have a rim-joist board butted beside the I-joist with a 2.5" flange on the I-Joist. I don't know, I guess I could screw the 2x4 into that flange, but that's all the meat available unlike a dimensional 2x floor joist that would be plenty deep to screw into. I am considering gluing the bottom plate with construction adhesive, but damn that will be a pita to remove in the future. 

I could skin a sheet of 1/2" plywood along the face of the rim-joist board that is supporting that cut out, which would be about 11" depth + the height of the wall. This is the most solid method I can think of for now. I could install a tensioner system if I have more room to work with in terms of floor joists below the wall, but the wall is going to be on the edge of the opening because space is a concern, which means I can't just get underneath and install a simpson tensioner similar to decks with threaded rod going up through the floor, bottom plate of wall, and threaded into a tensioner high up in the wall. I would feel more comfortable using a 4x post at the end of the wall, but since the stair cut out is a long L with about 2' of extra floor notched out for stair headway, My wall will have a zig-zag in it which would require 2 additional posts or at least 1 more additional 4x post at the 90 degree corner. I'll keep thinking on it.

Keymaster, that is correct. The only tie I can find is this. The local yard only has the common triangle piece that screws into the truss from below. The one from HD there looks like I could get it to work if I rig up a long enough extension so my drill doesn't get in the way. Any links to the one you have shown that I can buy outright without too much extra cost? Not following you 100% on the strap idea unless you mean the hurricane strap. I don't have access to feed the strap over the top of the header...so the only method to attach to the header now is to screw through the 3/4 plywood and into the header material. Looks like the hurricane tie would work, just means extra wood will be needed to hide the strap fasteners from showing at the riser.


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