Replies

1. 
   Sphere | Jul 28, 2007 11:25pm | #1

   A lot of local codes don't allow open risers..check b4 ya get too jiggy with it.

    

1. 
   traini | Jul 28, 2007 11:47pm | #2

   i have gone over the stairs with the building inspector and It is not covered by the Ontario building code and was told Ontario has no regulations concerning the large open space that would allow a child to fall through, given this info    the owner would like me to proceed.

   George

1. 
   Sphere | Jul 28, 2007 11:54pm | #3

   Good deal.

   I'd be curious how much meat is left after you cut the triangle away. A 10" wide stringer is pushing it. But the angle of the incline is going to dictate how much is left ....and a TRUE 10" tread width, is tad narrow for most rise/run combo's..11 is much more common. 

1. 
   traini | Jul 29, 2007 12:28am | #4

   The best lay out for these stairs is a 9 3/4" thread with a 1" nose  however the stringer required is then 17'3 and not a chance to find a 17'3 2x10 or 2x12 piece of maple. Have thought of  laminating 3 1x10 or  3 1x12 to give me a full 2.25 wide stringer and may allow for the 17'3 length. Even thought I could use a 2x6 Maple with 1x12  cut out  on either side leaving a revel under the thread for the stringer.

   George

1. 
   Sphere | Jul 29, 2007 12:43am | #5

   Laminating 3 1 by 12 sounds like a clamping night mare, I have a LOT of clamps, but not THAT many.

   Why not edge your 2x10 stringer with a 2x2 on the front (top) so that the 2x10 is not comprimised as bad.? That would give you more "beef" on the back side, where you need continous grain. 

2. 
   Ragnar17 | Jul 29, 2007 03:56am | #6

   George,

   Are the stair stringers to be unsupported the entire run of 17 risers? 

1. 
   traini | Jul 30, 2007 03:16am | #7

   Yes the owner wuld like to see them unsupported and I am finding it hard to find any info as to how heavy each stringer would have to be. I do not mind laminating as many pieces as needed.

   George

1. 
   Ragnar17 | Jul 30, 2007 07:51am | #11

   Thanks for clarifying that this is an unsupported run (i.e. freespanning). It also sounds like you are going to notch (cut out triangles) the stringers to accept the treads.The standard approach that I see in framing "normal" stairs is to use three (3) 2x12's for the stairs --- one 2x12 on each side and one down the middle. An un-notched 2x4 is sistered onto the bottom part of the 2x12 to increase bending strength.So I definitely think that using 2x10s will NOT be strong enough -- not by a long shot. Keep in mind that the bending strength of a beam is a cubic function of its depth (I = 1/12 b*h^3, where h is beam depth). The species of the beam also plays a role, but it is only a simple linear relationship (not cubic).Have you thought about using a different species of wood, or even an engineered product for your stringers? It's going to be critical to get them both long enough and deep enough to meet structural demands. Maybe it would be possible to laminate them with some maple veneer.Hope that helps.

3. 
   ponytl | Jul 30, 2007 04:28am | #8

   If you are like many on this forum... you know in your heart of heart what will work... which is usually overkill  but... it's the way many of us work...

   I don't think you'll find engineered plans for what you want to build and I don't think you'll want to pay to have them drawn

   i do think a 2x10 for a tread is not deep enough  but i can see adding to it so that you have something close to a full 11" tread with a 1" nose...

   for your stringers I've read and seen where they laminate plywood and veneer over it... which might be an option...  the other option I'd at least look into is something special from the mill (if there is one near you that can custom mill it) many times this is far cheaper than you'd think and a huge time saver... i was once able to buy 4" x12" x 20ft  cheaper from a mill than i could have purchased 2x12 stock from the yard..

   good luck

   p

1. 
   traini | Jul 30, 2007 04:46am | #9

   Thanks

   there are a few suppliers for a rough lumber in Toronto and I will call then on Monday.

   Thanks again

   George

1. 
   Hudson Valley Carpenter | Jul 30, 2007 06:36am | #10

   Have you considered mortising the stringers to accept the treads? 

4. 
   RogerEverett | Jul 30, 2007 05:47pm | #12

   George:

   If I were doing this job-- I would design it to only have 2 stringers/ skirts, but for that run, I would want to get material that is atleast a full 2" thick or better yet 2 1/2" X 12". For the treads I don't see any problem w/ 2 x 10. I would also lay it out, test fit 1 of the stringers and mortice out for treads, no cutting of the stringers. Another option would be to use metal angle screwed to stringers to mount treads to. Using the thicker stringers, would be good insurance against any spring while more than 1 person is walking on stairs. i am assuming the entire stairs is open on 1 or both sides.

    

   Roger

1. 
   traini | Jul 31, 2007 03:48am | #13

   Roger

   Thanks for the info

   It looks like I am going to use 2 stringers made up of either a 3x12 or two 2x12 glued

   open risers and open ends with a 4" over hang  7 5/8 riser with a 9 3/4" run

   total stringer length 17'

   George

1. 
   Ragnar17 | Jul 31, 2007 05:35am | #15

   It looks like I am going to use 2 stringers made up of either a 3x12 or two 2x12 glued

   Unless I'm missing the picture, I'd still be very concerned that's not going to cut it.  The doubled 2x12 option, for example, is only going to yield something like a doubled 2x4 after you get done cutting your notches out.

   I just can't see a doubled 2x4 (or pair of them, actually) being structurally adequate to support a 17' run of stairs.

2. 
   BilljustBill | Aug 03, 2007 03:02pm | #20

   Traini,

   In the IRC guildlines, I believe that the most length without a landing is set at 12'. And any stairway is limited to a max 7-3/4" rise.  These guidelines really helped me.

   http://stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf

   I'm finishing an L-shape set of stairs with an 8' run to a tier level, and then another 8' run to get to the second story.  I used 2X 12's and cut 4 stringers for each tier with a  48" wide stairway.

   On a 2X12 stringer, the uncut width is getting a little narrow for strength and bounce, so I glued and screwed a 2X6 of yellow pine on each side and added that 4th stringer.  On just an 8' long run, adding those two things makes a real positive difference.

   My stairs will be used as the climber has both arms full of bulky and heavy items both going up and coming down.  Its rise is 6-1/2" and finished width treads are 11-1/4".  Oddly, while attending a garage sale, I saw a set of steps like you are describing, except it was on the outside wall of garage apt.  Man was it steep and the handrail had been used so much that morning that I could see the shiny steel of the nails as they begain pulling away!!  The stairs you've planned are really steep and the steps are narrow for most people to safely use.  Miss one step, and anywhere on that 17' run is a long and steep tumble....

      Some food for thought,

    Bill

   Edited 8/3/2007 8:06 am ET by BilljustBill

   Edited 8/3/2007 8:12 am ET by BilljustBill

2. 
   fingersandtoes | Jul 31, 2007 04:44am | #14

    "Another option would be to use metal angle screwed to stringers to mount treads to."

   I was thinking the same thing. I have seen a several different stair designs built that way, and they all looked very good. For purely aesthetic reasons, I probably use something like a 3x8 for the stringers rather than a 2x10.

5. 
   ClaysWorld | Jul 31, 2007 07:33am | #16

   Get in touch with this Master. He can probably steer you to some boards and such.

    StanFoster

   And if you search some of his projects you will get some great Ideas.

6. 
   ClaysWorld | Aug 03, 2007 12:11am | #17

   I'm curious if you found any solutions?

   I was looking around and without direct contact to a sawmill or supplier couldn't find ? 8/4 or 10/4x 18' maple but take a look at this.

   It lists to 18'(extra long) at http://www.glenoaklumber.com/noflash/veneeredbds.html

   Using precision finger-jointing, edge-gluing and laminating technology, Glen Oak produces large quantities of the product Mother Nature cannot. Manufactured wood core veneered boards are engineered to be both wide and long. They are sanded with a 120-grit finish on top and bottom, with a moulded edge. Veneered Board Core Finger-jointed edge-glued wood core High quality veneer, top and bottom • Red Oak • Select White Hard Maple • Cherry Dimensions • Nominal Widths: 6", 8", 10", 12" • Thickness: 3/4" • Lengths: 8', 10', 12', 16', and 18' (extra-long!) Benefits and Advantages • Superior to natural lumber • Won’t cup, bow or twist • Defect-free, completely useable • Even grain and color • Excellent machinability • Long lengths • Perfect for shelves, wall caps, stair stringers or skirt boards, false ceiling beams, drawer fronts and more

7. 
   mike_maines | Aug 03, 2007 02:20am | #18

   Ragnar17's right, don't use 2x10's for stringers, bending strength is based much more on depth than on width.  I always use 2x12's for stringers, which leaves you with more or less a 2x6 worth of meat left.  A 2x10 only leaves you a 2x4 worth of strength.

   I use four stringers most of the time.  With only two stringers, and 17 risers, you need all the help you can get.  That's a long stair for unsupported stringers.  They won't break, but they will be very inclined to vibrate a lot.  Is there any way you can add a support midway?  If not, you need to look into something like 3x14" or 3x16" stock.

1. 
   Burkebuilders | Aug 03, 2007 02:47am | #19

   why not use a 20' LVL and veneer it with 1/4 maple ply and cap with a solid 3/8 peice of maple??

1. 
   mike_maines | Aug 03, 2007 03:20pm | #21

   I like the sound of that.