Stairs Stringers / Horses

[JayHawkInspector]

I thought the over cutting of stair stringers wasn’t allowed but I can’t seem to be able to find it.

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[fatboy]

You won't find it in the code, it's a workmanship issue........ actually.....the lack of.......

 

[Glennman CBO]

Is that hem-fir? It's already weak enough, let alone the overcutting!

 

[globe trekker]

JayHawkInspector,

Technically, the structural floor member HAS been overcut! See if Section R502.8 in the `06 IRC applies.

R502.8 Drilling and notching.

Structural floor members shall not be cut, bored or notched in excess of the limitations specified in this

section. See Figure R502.8.

While I also agree that it is "poor workmanship" and a very common practice, I think that you could

apply this code section AND Section R301.1 to have them install additional bracing for the ' overcuts '.

Just my 2 cents worth!

.

 

[Bootleg]

Does the stairway feel spongy?

 

[Yankee]

I'm pretty sure I read somethin gin the code about overcutting recently. I'm going to say it might be referanced in the deck building guidebook based on the 09 code. If I find it, I'll let you know.

Editrescriptive Residential Wood Deck Construction Guide based on 2009 IRC written by AF&P (free to download), do a google), page 17, Figure 28 has a couple of dimentional requirements. . . . max 6' span southern pine must leave 5" of stringer.

 

[GHRoberts]

Fortunately the risers and treads add strength to the structure. Unfortunately there is no prescription that allows us to easily determine what the actual strength is.

If the stairs feel reasonable during a test walk, pass them.

 

[peach]

I always use the notching provisions for floors.. that's not overcut as much as you sometimes see them. Even if it's not spongy now, the chances are pretty good the stringer will split over time.

 

[Paul Sweet]

Do these stringers span from floor to floor, or are they nailed into adjacent walls, or resting on knee walls?

 

[Mule]

In my opinion I don't think you could actually call this a floor member. If you did consider this a floor member then the entire stringer violates every notching don't's out there.

Also there is not anything in the framing section about workmanship either.

There is not anything in the code that specifies how much, how little, or whatever on stair stringers. There should be but.............

 

[SCBO1]

Timberstrand LSL used for stringers has a DO NOT over cut stair stringer requirement in their guidelines. What happen to hand saws!

 

[peach]

if a stair tread isn't a floor, what is it? (a wall?)

 

[GHRoberts]

if a stair tread isn't a floor, what is it? (a wall?)

It is a stair. I believe that the design load is much different than the design load for a floor.

 

[Mac]

"Feeling reasonable" while walking on a stair - is that a technical term? It's a poor method of approving anything.

People carry all kinds of stuff up & down stairs, like refrigerators, pool tables, hot tubs. I'd want the designer to see & approve them.

 

[pwood]

It is a stair. I believe that the design load is much different than the design load for a floor.

gh,

if you have access to a code book you might want to look at table 1607.1 item 36!

 

[peach]

so it's a floor with a minimum concentrated load of 300 pounds in a 4 sq in area.. where is it in the IRC?

it's a floor

 

[Mule]

peach, gotta disagree on this one.

If it's a floor then the notching of the stringers are in violation of the code and shouldn't be allowed to be installed.

Most residential stair stringers are made from 2 X 12's. When you notch the stringer to accomodate the correct rise and run there is around 6" of board left.

That amount does not meet any code for notching of floor members.

Notching shall not exceed 1/6 of the framing member. 1/6th of a 2 X 12 is about 2".

Notching shall not be in the middle 1/3 of the framing member. Stairs violate that prevision of the code also.

If you consider a stair a floor then by allowing the stringers to be notched violates everything you're not allowed to do. Or should I say violates everything you are not supposed to do.

 

[Yankee]

I'm pretty sure I read somethin gin the code about overcutting recently. I'm going to say it might be referanced in the deck building guidebook based on the 09 code. If I find it, I'll let you know.Editrescriptive Residential Wood Deck Construction Guide based on 2009 IRC written by AF&P (free to download), do a google), page 17, Figure 28 has a couple of dimentional requirements. . . . max 6' span southern pine must leave 5" of stringer.

I will go with the AFPA as the referanced standard.

 

[peach]

let's write a best practices/Code change for stair stringers, then..

 

[GHRoberts]

gh, if you have access to a code book you might want to look at table 1607.1 item 36!

I believe the design load on floor joists is perpendicular to the joist. That is not true for stair stringers. Much different.

I guess I should also say that once the cuts are made in the stringers the lumber needs to be regraded. Just all sorts of problems.