Replies

1. 
   RogerEverett | Apr 29, 2006 03:38am | #1

   According to IRC, min. tread depth -- 10", as measured from adjoining vertical surfaces ( risers ). Nosing is, min. 3/4" to max. 1 1/4". So if you go with 10" tread measurement and 1 1/4" nosing, you would have tread at 11 1/4". Nosing doesn't count as part of tread depth. BTW in IRC max riser is 7 3/4".

   That said you might check with your local building dept. for any changes for local codes. In my area ( Fl. --residential ), min. tread depth is 9", max riser 7 3/4". Also there is a part which spec. 2 risers and 1 tread be between 24-25".   As an example  2- 7 1/2" risers, and 9 1/2" tread = 24 1/2", right in code.  As for nosing our min.,max. is same as IRC.  Personally I use a 1 1/4" nosing with 1/2" roundover, in that a 1/2" roundover with a 5/8' trim under = 1 1/8" which gives me 1/8 flat revel, which is just enough for trim to fit up tight with out any gap, that might happen if trim extends to where roundover starts

   HTH

   Roger

1. 
   edward3 | Apr 29, 2006 09:35pm | #2

   Thanks for the info. This is one of my typical "overthinking til' it doesn't make sense" issues. It was ( Page 5, Photo #8 ) of the link below that struck me as odd.http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf

2. 
   Soultrain | Apr 30, 2006 04:43am | #3

   The MINIMUM is 10".  It can be bigger, so 10 1/2" would be fine.

3. 
   xosder11 | May 04, 2006 11:22pm | #4

   not to beat a dead horse here, but I still think your original assumption is right.
   Page 5 says that "the tread depth shall be measured horizontally between the vertical planes of the FOREMOST PROJECTION of adjacent treads and at a right angle to the tread's leading edge"

   it is also shown that way in the diagram. You measure nosing to nosing.

   Where the confusion lies is the fact that there is a discrepancy between the way you are defining "tread" ( I assume you mean the actual piece of material that you are buying precut and installing) and the way the IRC is defining "tread" as the DISTANCE from nosing to nosing.

   So in conclusion, the IRC is saying 10" tread minimum is OK per their definition, but if you want to build to code the depth of the actual "treads" you buy are going to have to be a minimum of 10 3/4" deep (plus if the tread is going under the riser you need to add the thickness of the riser)

   Does that help? Or am I actually confusing everyone more? Or am I confused? Huh?

   
   

   ---

   Edited 5/4/2006 4:47 pm ET by xosder11

1. 
   Snort | May 05, 2006 02:29am | #5

   R314.2 Treads and Risers...min. tread depth shall be 9"...tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread's leading edge...R314.2.1 Profile...A nosing not less than 3/4" but not more than 1 1/4" shall be provided on stairways with solid risers...Exceptions:1. A nosing is not required on stairs where the tread depth is a minimum of 11".2000 IRC/NC 2002 I need a dump truck, baby, to unload my head

1. 
   xosder11 | May 05, 2006 03:36pm | #6

   It looks like since 2002 the IRC revised to make tread min 10". See the link previously posted.