Rough-Framed Stairs - 04

Rough-Framed Stairs - 04


Some designers and architects are pretty savy when it comes to drawing things as they are in reality…others, not so much.

Making sure that the stairs you will be building are made IAW all governing codes and meet your needs takes some consideration early on.  There is nothing worse than sketching out your perfect dream home, getting every room perfect, then putting the stairs “wherever they will fit” and hoping for the best.

So lets talk about these things.

IRC/IBC Riser Code

The International Residential Code (IRC) prescribes specific requirements to be met when building stairs to be compliant.  They are found in the 2012 IRC at R311.7 Stairways.

Sometimes the section view of a set of plans will have some riser and tread information provided by the designer.  

DO NOT ASSUME that his numbers are correct.

The following technique is something I have developed over the years to quickly determine riser options while in the field, incase the builder is looking to make changes.

I use a scientific calculator (HP50G) so the steps here might be a bit much, but you will see the process and you can determine how you will tackle this problem yourself.

FF2FF Height

So starts my short-hand.  

FF2FF HT:  Finished Floor to Finished Floor height.  This is very important to know.  It starts with measuring on site or beforehand, knowing the exact sizes of the materials being used to determine the exact elevation dimension ffrom the lower to upper rough floor levels.  Then, you take into consideration the floor coverings/surfaces that will be applied as finishes.

The calculations are all done using finished floor surfaces (if known) and then you add the depth of the lower floor surface to the bottom of your stringers that contact that lower level.


Also, its always a good practice to place your lower stringers on PT plates if on concrete rather than straight onto the concrete.

I will have more on this topic as time permits.  

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