Replies

1. 
   Mark | Jun 15, 2006 06:08am | #1

   How about glue lams or microlams?  you can get them in 14", 16"  and wider widths.

   " If I were a carpenter"
1. 
   toledo | Jun 15, 2006 06:12am | #2

   can you get them in an exterior grade....?

2. 
   trout | Jun 15, 2006 06:40am | #3

   A clean looking solution is simply ordering a wider plank, or having a local custom mill whip one up. 

   The costs can be quite high, which is probably why steel stairs are popular when it comes to odd dimentions. 

3. 
   JourneymanCarpenterT | Jun 15, 2006 07:20am | #4

        The most practical way would probably be to use ¾” plywood.  Instead of 3 stringers, make 6.  Then glue, and nail or screw 3 of them to the other 3.  You now have 3 stringers at a thickness of 1 ½”.

    

        If the stairway is less than 36” wide, (and thus requiring no center stringer) you could simply use cleats.  An idea popped into my head just now for stairways with cleats that are wider that 36”.  Frame a wall as a center stringer, the top of which will take on the form of an actual stringer.  That’s quite a bit more involved than the plywood, but might be practical in situations where a wall is desired somewhere in that location anyway.

    

        Using an LVL beam, or the less expensive LSL beam, is pricier, but often done.  This is the most obvious option.  Of course, other beams such as glue-lams are also a possibility.

    

        Finally, here’s an alternative that raises doubts about professionalism, but is used by some contractors in my area.  (There are no building inspectors here.)  First fasten a 1x12 to the wall.  Then fasten the 2x12 stringer to the 1x12.  The problem with extra deep steps is that the distance from the point where the tread and riser meets, to the bottom of the stringer, is less than 3 ½”.  If the 2x12 is secured well to the 1x, the stress should no longer be felt as much at this weak spot, but transferred to the adjoining piece of lumber.

    

        You should note that I view this last method as cobbling, and do not recommend it.  If you have to skip a meal or even three to spring for the plywood, I suggest you make the sacrifice.

   -T

1. 
   Ragnar17 | Jun 15, 2006 07:33am | #5

   First fasten a 1x12 to the wall.  Then fasten the 2x12 stringer to the 1x12.  The problem with extra deep steps is that the distance from the point where the tread and riser meets, to the bottom of the stringer, is less than 3 ½”. 

   T,

   If the stringer is attached to the wall (i.e. nailed at 16" oc), then the stringer will not be subjected to bending stresses, and the extra-deep notches should be insignificant (from an engineering perspective).  The only time that the notch depth comes into play is when the stringer is free spanning.

    

2. 
   davidmeiland | Jun 15, 2006 07:35am | #6

   Plywood would make horrible stair stringers, whether notched or done with stair angles. The exposed edges of the ply will quickly absorb water and turn it into punk. Sandwiching three layers together makes it even worse.

   Wide solid boards are a good answer. I was at the small local sawmill I buy from and he was cutting so 3x16 doug fir planks for someone's dock. Awesome boards, the kind of wood that makes you want to BUILD SOMETHING.

   Glu-lams are available pressure-treated. If you notch them then talk to the manufacturer about appropriate ways of treating the cuts.

1. 
   JourneymanCarpenterT | Jun 16, 2006 08:12am | #14

        "Plywood would make horrible stair stringers, whether notched or done with stair angles. The exposed edges of the ply will quickly absorb water and turn it into punk. Sandwiching three layers together makes it even worse."

        First, it should be noted that it is incorrect to say I recommend ‘sandwiching 3 layers of ply together.’  I recommended 2 layers, each ¾”, and equaling a total of the usual 1 ½” thick stringer.  Three ¾” stringers secured to three ¾” stringers.  Six ¾” stringers, making up three standard 1 ½” stringers.

   <!----><!----> <!---->

        Second, exactly what water will the “exposed edges of the ply” quickly absorb so that it will be turned into “punk?”  Are you aware that plywood is often used for treads and risers on stairs that will be carpeted?  Sandwiched plywood is often used for top and bottom plates in radius walls, as well as radiuses for a great many other things.  How is it you figure that plywood stringers would be so much different?

   <!----> <!---->

        In regards to comments made by others about the rise getting shorter as the run gets longer – and thus leaving plenty of meat on the 2x – is a good point, especially since toledo may not have considered it.  However, he only specified deep “steps,” which can include a deeper rise as well as run.  Because he posed it as a hypothetical situation, I didn’t really give much consideration to what he might need it for.-T

1. 
   davidmeiland | Jun 17, 2006 07:18am | #16

   OK, two layers, three layers, whatever... you are recommending plywood as stair stringer material for an exterior stair (see his original post, it says exterior) and of course that means water unless you live in the Mojave Desert. Maybe he does. I stand by my comment... terrible material for the project. There are any number of other, much better materials.

1. 
   JourneymanCarpenterT | Jun 17, 2006 07:39am | #17

        “see his original post, it says exterior”

   <!----><!----> <!---->

        Good point, I didn’t notice that.  I think though, that if I was going to build a set of steps with treads and risers totaling far greater than the standard 17”-18”, I’d also choose a wood that would better resist decay.  Perhaps cedar, redwood, or cypress.-T

4. 
   Ragnar17 | Jun 15, 2006 07:50am | #7

   Toledo,

   Are you sure that the deeper treads would result in an unsatisfactory stair jack?

   I just sketched up a few jacks with deep treads, and they didn't seem to impact the minimum bending thickness much at all.

   Also, keep in mind that deeper treads will generally result in a shallower rise, since all the rules of thumb for determining rise and run factor them as inversely proportional to one another.  This shallower ascent angle makes for an even thicker minimum section in bending.

1. 
   toledo | Jun 15, 2006 02:38pm | #8

   thanks for the ideas, folks - I'll look into these options, while hoping the client will settle for normal stairs....

2. 
   jvhannah | Jun 16, 2006 06:52am | #13

   Nobody picked up on your comment.  You are correct as the the tread gets long the rise is reduced and the stringer is laid closer and closer to horizontal.  Even when the treads approach 24" and the riser cut gets very short so the remainder of the stringer is still quite adequate.   I did a set of steps for an older HO that was very solid (Three Stringers).  I don't remember the exact dimensions but I was careful to use the recommended ratios so the steps walk well even for an older user.  i.e. very low rise.  The disadvantage is that the run gets fairly long however.  In this case it was a set of steps for a deck and the concrete landing was pulled out further from the deck and all worked out OK.

   Jim

1. 
   toledo | Jun 17, 2006 06:00am | #15

   yeah, yeah, so I'm not a stair builder...you guys are right of course - I did a 6/12 mock up for the client, and there was of course plenty of meat left...live and learn....

5. 
   hammer1 | Jun 15, 2006 04:00pm | #9

   I've never liked cutting out sawtooth stringers. Even with normal size treads and risers, the meat that is left is questionable in strength. I prefer to cut triangular blocks to match the tread and riser and screw them to a solid stringer. It's very easy to cut consistent and accurate blocks and position them on a 2x6 or 2x8 so that the stringers are exactly the same. You have to be careful, using too wide a stringer, and limiting head room under the stair. I've done a lot of stairs this way and it's pretty nice not to have to do any significant shimming when installing treads and risers. This isn't a great picture, but you can see the rough stringers in the background as well as a set of move around, temporary construction stairs in the front.

   Beat it to fit / Paint it to match

   
1. 
   toledo | Jun 16, 2006 06:31am | #12

   ok, now I've got too many options....great - thanks guys....

6. 
   bobl | Jun 15, 2006 04:13pm | #10

   I wanted something different for our deck.

   used a 2x12 and then nailed 2x6 to 2x12 to put the treads on. used 2x12 for treads,

   2x6 not cleats as they extended past the 2x12 the length of the tread.

    

   bobl          Volo, non valeo

   Baloney detecter

7. 
   sungod | Jun 15, 2006 05:02pm | #11

   Don't cut the stringers, just attach brackets to hold the threads. Otherwise lengthen the run so the rise won't be so deep. Prepaint the stringer before attaching threads, it will extend its life

8. 
   Matt | Jun 17, 2006 02:47pm | #18

   Re JVHannah (sp?) comment about making the rise smaller for wider treads, there are some simple formulas for figuring this out . 

   Here is an excerpt from another document:

   Comfortable stairs:

    

   In order for stairs to walk comfortably, the rise and run of each stair should be in a particular, approximate relationship to each other.  The lower the rise, the wider the run (tread).  Stairs that do not have this relationship properly accounted for may cause people to trip when ascending or descending.  Here are some basic rules of thumb. Use one of them:

    

   §         The rise times the run should equal approximately 75. §         Rise plus run should be between 17" and 18". §         Two times the rise, plus the run should equal 25.

    

    

    

    

    It is not unusual for exterior stairs to have smaller rise and wider tread, particularly if there is only a few steps, or if they are stone, etc that are set into a hill.  I like using the 1st rule above but usually go for a smaller number than 75 for exterior steps. 

   12" treads are not all that wide for exterior stairs.  Wide treads might be 14 or so.

    

   A little tangent: In commercial construction in my area, at grade steps are required to have a rise of no greater than 6" and a tread of no less that 12".  5.5" is often used as a rise on concrete steps based on the width of a 2x6. 

   RE the guys statement of steps less than 36" wide not needing a center stringer... I'll have to disagree with that.  Just about any tread material will sag over time with close to a 36" span.  For me, anything much over 36" wide gets an extra stringer (4 total).