Changing Stairs to meet code

Started by rauckland, April 23, 2008, 02:32:22 PM

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rauckland

I am building the 1 1/2 20x30 cottage and have added 10 feet to make it 20x40.  I want to use the standard "U" stair included in stair options but am confused.  On the side of the stair options paper standard U stair it says 6T@10" = 5'0 or 6T@9"=54".  It also says 36 1/2 " are needed for the landing and eith 5' or 54" for stairs depending on the tread. Our building code in Ellensburg says the Run(depth of a tread) must be at least 11 inches,so how do I make these stairs work?  I allowed 6'5" of room for the wide of them but how much room do I need from the wall out to make these work?  The code also says the Rise (height of the step) has to be between 4 and 7 inches and not vary in height more than 3/8 inch from shortest to tallest.  headroom must be a minimum of 80 inches clear overhead.  Am I safe in assuming that 6T@10" means 6 stairs or tread with the dept of the tread being 10".  So to meet our code I need to made more tread but they need to be 11"?  Can you give me some advice.  I have submitted the plans to the building department already and just attached the Standard U Stair for them to look at, but I am afraid they won't pass it.  HELP

John Raabe

Rauckland:

I'm sorry I haven't jumped on this earlier. I thought I had answered this in an email to you but perhaps that didn't get to you.

The stair options plans (sheet 3 in the bonus details booklet) shows the "Standard U Stair" plan with two options as to the tread depth. The width of the stair will be the same (6'-4 1/2" inside the walls) but the length will change depending on which tread depth you use. For 10" deep treads the run of the stair will be 5' (6T @ 10"). For a 9" tread and a steeper stair your 6 treads equal 54". To this you add the depth of the landing 36 1/2" to get the total stair length.

Draw a line through or white out the steeper stair dimension for your plans and use the 10" treads dimension. Some jurisdictions allow the steeper stair but I think you are in WA state where the IRC wants a Max rise of 7- 3/4" and Min run of 10". That stair will meet those requirements.

Sorry for any confusion. Your plan checker has probably already figured this out for you.  ;)
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