cutting stair stringers

jimmy21 · 11-30-2011, 10:03 PM

Quote:

Originally Posted by woodworkbykirk

any person walking up or down a flight of stairs will develop a memory in regards to how much to raise their foot to walk up the stair comfortably,, any more than 3/16" becomes very awkward and makes it more likely for the person to trip.. hence our code of max riser variance of 1/8"

what are you framing your stairs with to have more than 13 rises in a straight flight of stairs and not have issues with the stair sagging our bouncing? 2 ply lvl's

we have much stricter codes in a number of areas for different trades

one of the scariest ive heard is regarding your electrical,, cant remember teh exact distance but you can have as many outlets as you can fit within so many feet. here you cant have more that 12 outlets or light boxes per circuit. with out code electrical fires are far less likely to happen as

I think here your allowed 1/4 or more varience. But it doesn't matter, my stairs turned out perfect. Within 1/16. This had 10' of rise because its 8' of headroom, plus a 2x12 plus 18" grade change.

I'll just have to call the ahj tomorrow to find out about a landing. Hopefully it really is 12' rise. Which I'm only at 10'9. Landing would be stupid in this situation. This is just access to storage over my garage. If the stairs have significant bounce I will just put posts under the midpoint. The stringers are 2x12 reinforced with 2x4

titanoman · 11-30-2011, 10:15 PM

Or frame under the stairs and call it storage.

**BigJim** · 11-30-2011, 11:26 PM

Quote:

Originally Posted by jimmy21

I think here your allowed 1/4 or more varience. But it doesn't matter, my stairs turned out perfect. Within 1/16. This had 10' of rise because its 8' of headroom, plus a 2x12 plus 18" grade change.

I'll just have to call the ahj tomorrow to find out about a landing. Hopefully it really is 12' rise. Which I'm only at 10'9. Landing would be stupid in this situation. This is just access to storage over my garage. If the stairs have significant bounce I will just put posts under the midpoint. The stringers are 2x12 reinforced with 2x4

If you cut an 11 + run out of a 2X12, you will for sure have bounce if not dangerous, that is getting a little thin on the back of the rise/run cut.

jimmy21 · 12-01-2011, 01:33 AM

Found my answer on the landing. 12' is correct. So I'm in the clear on that

R311.5.4 Landings for stairways. There shall be a floor or landing at the top and bottom of each stairway. Exception: A floor or landing is not required at the top of an interior flight of stairs, provided a door does not swing over the stairs. A flight of stairs shall not have a vertical rise greater than 12 feet (3658 mm) between floor levels or landings. The width of each landing shall not be less than the stair-way served. Every landing shall have a minimumdimension of 36 inches (914 mm) measured in the direction of travel.

To take care of bounce, I'm going to reinforce them with 2x6. If it still has bounce, i will put 2 vertical posts with a horizontal at mid point

jimmy21 · 12-01-2011, 01:36 AM

Quote:

Originally Posted by jiju1943

If you cut an 11 + run out of a 2X12, you will for sure have bounce if not dangerous, that is getting a little thin on the back of the rise/run cut.

I was left with 5.5. Didn't seem any smaller than any other stringer to me. Its perfect for a 2x6 to sister to

Willie T · 12-01-2011, 09:15 AM

Removed by poster.

Willie T · 12-01-2011, 09:48 AM

This one should get you just what you are looking for. And, using 17 treads, it keeps you within code, except for the fact that you can only go 84" on a span with cut stringers like this, not 170+. You'd be within code, I believe, if you used solid stringers.
This drawing assumes 1-1/2" thick treads. And it puts one tread at the top deck height.

Willie T · 12-01-2011, 02:39 PM

While I'm thinking about it...............

Since there always seems to be a lot of concern about not leaving enough "meat" in the stringers after cutting out for the risers and treads..... I do hope everyone knows THIS trick....

All you do is shift your cut layout 1" out into the space alongside the 2x12.

This gives you one more (additional) inch of supporting run in the stringer without sacrificing anything.

It is not necessary, at all, to have those "points" on your stair stringers. In fact I know that some of you who have cut many stringers have knocked off a corner every now and then. What did you do? You probably picked it up and tried to glue or tack it back into place...... Right? Do you honestly think that did a bit of good? C'mon, think about it. The points do nothing. You never even nail out there, and the riser boards support the treads anyway..... NOT that flimsy, fragile point of wood.

This drawing shows stringers made for identical rise and run.... one cut with points (thus leaving you with only 5-1/8") and one with a shifted layout (leaving you with 6-1/8")

You sometimes have to learn to think outside the box. But keep in mind that stringers of this type and length would be illegal on a deck.

titanoman · 12-01-2011, 02:49 PM

Quote:

Originally Posted by Willie T

While I'm thinking about it...............

Since there always seems to be a lot of concern about not leaving enough "meat" in the stringers after cutting out for the risers and treads..... I do hope everyone knows THIS trick....

All you do is shift your cut layout 1" out into the space alongside the 2x12.

This gives you one more (additional) inch of supporting run in the stringer without sacraficing anything.

It is not necessary, at all, to have those "points" on your stair stringers.

This drawing shows stringers made for identical rise and run.... one cut with points (thus leaving you with only 5-1/8") and one with a shifted layout (leaving you with
You sometimes have to learn to think outside the box.

Unless you're not using risers. And, before you have a pattern, you really need a framing square, which will be tricky for the layman (not you or I) to figure w/o that leading point to measure from.

Willie T · 12-01-2011, 03:00 PM

Quote:

Originally Posted by titanoman

Unless you're not using risers.

Then it is still only aesthetics. The support from a tread with no risers comes from the thickness of the tread, not from that little corner that you wouldn't dare tap with a hammer (or nail into).

As you walk up those stairs, you are depending on the quality of the fastening system toward the rear of the treads.

Does it look better with the points still there? Sure. But that is about all they really do.

Willie T · 12-01-2011, 03:08 PM

Quote:

Originally Posted by titanoman

Unless you're not using risers. And, before you have a pattern, you really need a framing square, which will be tricky for the layman (not you or I) to figure w/o that leading point to measure from.

True. But, although I just wing it, there is an easy way a novice could handle that challenge.

Rip a 1" piece to lay next to the raw, uncut stringer, and work off that edge.

woodworkbykirk · 12-01-2011, 08:40 PM

referring to how much meat is left in the stringer after the notches are made is called "effective depth",, a 2x10 stringers is the minimum allowed here, it just works out to have 3 -1/2" of depth left in the stock. i use 2x10 for stairs with up to 7 rises, then i either up it to 2x12 or even 11- 1/4 lvl's for long flights of stairs.. you want a stair with nearly no bounce at all use lvl.. heavy as hell though..

titanoman · 12-01-2011, 09:01 PM

Quote:

Originally Posted by woodworkbykirk

referring to how much meat is left in the stringer after the notches are made is called "effective depth",, a 2x10 stringers is the minimum allowed here, it just works out to have 3 -1/2" of depth left in the stock. i use 2x10 for stairs with up to 7 rises, then i either up it to 2x12 or even 11- 1/4 lvl's for long flights of stairs.. you want a stair with nearly no bounce at all use lvl.. heavy as hell though..

I would never go down to 2x10 for any reason. As it is, that leading corner is always ready to break off anyway because of the way the grain runs, but still...

jimmy21 · 12-01-2011, 09:08 PM

The stairs don't seem to have too bad of a bounce. Enough that it would be annoying in a house but mine will rarely be used. Have to actually jump to get movement. The real problem seems to be racking back and forth. Maybe it would go away when the stairs are complete but just with treads on, it moves pretty easy. Im going to sink some 4x4 posts into the ground to double as reinforcment and part of the railing system.

titanoman · 12-01-2011, 09:16 PM

Quote:

Originally Posted by jimmy21

The stairs don't seem to have too bad of a bounce. Enough that it would be annoying in a house but mine will rarely be used. Have to actually jump to get movement. The real problem seems to be racking back and forth. Maybe it would go away when the stairs are complete but just with treads on, it moves pretty easy. Im going to sink some 4x4 posts into the ground to double as reinforcment and part of the railing system.

Run the posts all the way to the ceiling and it'll take out all the lateral sway.