Basement Stairs Bottom Tread in Angle - ICC


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Old 01-18-12, 11:40 AM
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Basement Stairs Bottom Tread in Angle - ICC

Not sure if this is the right forum, or maybe it should be under Carpentry.

I am rebuilding my basement stairs as part of the basement finish and I would like to turn the bottom two treads 90 degrees to the left (similar to the image below).
A carpenter friend who helps me on the job told me that it is against code to do that and I should check with my local building inspector. I called the inspector and he referred me to the 2009 ICC chapter 3.11...he said there are ways to do it, but he can't tell me over the phone.

Is there any way to access the ICC and this chapter in particular online to see how I can build this to code?

Thanks in advance.

)
 
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Old 01-18-12, 11:56 AM
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I'd run the stairs to the wall and have a landing there with the rest of the stairs needed coming into the room 90į to the rest of the staircase.
 
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Old 01-18-12, 12:36 PM
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We thought about that, problem is - we don't have enough head room. And the stairs won't reach the wall in front of them. Reason we wanted either a landing or an angled end was that we want to direct people into the finished area, instead of going down and straight, facing the electrical panel cabinet and then turn into the room. We actually thought building a 3' wall at the edge of the landing, but not sure it will look nice. That's when the angled bottom treads came up.

Do you happen to know if it is against code?
 
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Old 01-18-12, 01:08 PM
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Codes

This may or may not help:

Chapter 3 - Building Planning
 
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Old 01-18-12, 01:22 PM
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the 2009 International building code (IBC) produced by the International Code Council (ICC) does not address stairs in chapter 3. Chapter 3 is for "Use & Occupancy Classification". I believe you need to refer to chapter 10, "Means of Egress". Paragraph 1009.4.2 deals with riser height and tread depth. The problem is the maximum riser height is 7 3/4" (your sketch shows 8") and the minimum tread depth is 10" nosing to nosing (based upon exception #5 of this paragraph). Winder treads are allowed within a dwelling unit but I think your bigger problem is that you will need another riser to accomodate the max. height and the tread depth you show is not deep enough either because of the projection of the nosing. Your nosing must project 3/4" but not more than 1 1/4". It is often possible to get residental basement stairs approved that do not comply with these requirements but you will have to verify that with your local authorities. Sorry to be the bearer of bad news.
 
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Old 01-18-12, 01:50 PM
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@ spiper - this is not my sketch, this is just a picture of what I meant by angled treads, I just didn't have the professional term (winder treads) - thank you, I learned something new
And you are right - the inspector did let us keep the out-of-code stairs because the home is very old and there is no way to bring it up to code within the current structure. But we do have to re-build them because the structure of the stairs have seen better days ...and he said that we should simply remain within the current spechs. I am just trying to improve it.
 
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Old 01-18-12, 01:56 PM
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@ Wirepuller38 - thank you for the link! I'll double check with the inspector tomorrow.
 
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Old 01-18-12, 10:44 PM
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Granted, it's not quite current, but my 2003 IRC, Section R311.5.3.2 allows winder (truncated) stairs with a 10" tread depth, measured 12" in from the narrowest part of the tread. Absolute minimum tread depth at the inside is 6", as opposed to coming to a point like your sketch shows. It also requires only a minimum of 6'-8" overhead clearance above the tread nosing.

Maybe your local inspector would let you get by with something that conforms to that.
 
 

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