Consistancy in riser height throughout a run of stairs

Kevin M. Carr · 01-17-2011, 10:11 AM

I know that throughout a run of stairs the smallest to the largest rise can not exceed 3/8 of an inch. My question is from rise to rise what is the greatest difference that you can have? Can you have a difference of 3/8 of an inch?

Daniel Holzman · 01-17-2011, 10:30 AM

Page 17 of the Prescriptive Residential Wood Deck Construction Guide states:

Tread and Riser Detail: 7-3/4" maximum riser; height shall not deviate from one another by more than 3/8"

You should check your local code for your specific application.

Keith Mathewson · 01-17-2011, 07:47 PM

You answered your own question.

The difference from riser to riser isn't the primary consideration. The max difference between the shorted riser and the tallest riser cannot exceed 3/8" no matter where they are in the flight.

masterofall · 01-21-2011, 01:50 PM

Sounds like some lax codes in some areas. We have a 7-7/8 maximum riser with a 1/8 deviation not surpassing the max. Why not just make them all the same? It is just simple division and layout

Keith Mathewson · 01-21-2011, 07:40 PM

Those are from the 2006 IRC. The deviation usually occurs if the floors are out of level. If the first floor is out by over a 1/16" and the top floor is out by the same then unless you can get the BI to measure at the walk line you will be over an 1/8".

01-17-2011, 10:11 AM	#1
Kevin M. Carr Newbie Join Date: Jan 2011 Posts: 1	Consistancy in riser height throughout a run of stairs I know that throughout a run of stairs the smallest to the largest rise can not exceed 3/8 of an inch. My question is from rise to rise what is the greatest difference that you can have? Can you have a difference of 3/8 of an inch?

01-17-2011, 10:30 AM	#2
Daniel Holzman Civil Engineer Join Date: Mar 2009 Location: Boston Posts: 3,583	Consistancy in riser height throughout a run of stairs Page 17 of the Prescriptive Residential Wood Deck Construction Guide states: Tread and Riser Detail: 7-3/4" maximum riser; height shall not deviate from one another by more than 3/8" You should check your local code for your specific application.

01-17-2011, 07:47 PM	#3
Keith Mathewson Stair builder Join Date: Aug 2010 Location: Seattle Posts: 227	Consistancy in riser height throughout a run of stairs You answered your own question. The difference from riser to riser isn't the primary consideration. The max difference between the shorted riser and the tallest riser cannot exceed 3/8" no matter where they are in the flight.

01-21-2011, 01:50 PM	#4
masterofall Member Join Date: May 2010 Location: Kelowna B.\|C. Posts: 138	Consistancy in riser height throughout a run of stairs Sounds like some lax codes in some areas. We have a 7-7/8 maximum riser with a 1/8 deviation not surpassing the max. Why not just make them all the same? It is just simple division and layout

01-21-2011, 07:40 PM	#5
Keith Mathewson Stair builder Join Date: Aug 2010 Location: Seattle Posts: 227	Consistancy in riser height throughout a run of stairs Those are from the 2006 IRC. The deviation usually occurs if the floors are out of level. If the first floor is out by over a 1/16" and the top floor is out by the same then unless you can get the BI to measure at the walk line you will be over an 1/8".

Consistancy in riser height throughout a run of stairs