Chapter 3 Building Planning is “Enheightening”

New Jersey Architects use the International Residential Code2015 New Jersey Edition on a daily basis. It guides them in many decisions made during the design and construction document phases to get their client’s end result. Chapter 3 Building Planning is especially useful for determining many design requirements for your home. I have to believe that this chapter alone out of the other 43 chapters must have over a thousand requirements! I have not counted but I think my fellow architects would agree.

Vertical measurement by itself can probably account for hundreds. This section deals with 3/8” up to 60 feet! The following are a varied sampling of some:

3/8” is the maximum amount of difference between the smallest and largest riser height in a set of stairs.

1 ½” is the landing height below a threshold when the door swings out over the landing (8 ¼” is acceptable if the door swings in the opposite direction).

8 ¼” is the maximum riser height for a stair riser.

9 ½” is the maximum riser height for a ships ladder.

<18” is the height above the finished floor that makes glazing hazardous.

24” is the minimum height above the finished floor for a window opening that opens up to grade that is greater than 72” below. (That’s a double height requirement!)

30” – 38” is the allowable handrail height above the nosing on a stair, which also applies to a ramp surface (30” – 36” for a ships ladder)

36” is the minimum height for a guard rail at an open-sided walking surface.

6’-4” is the minimum beam height (or duct height) in a basement.

6’-6” is the minimum clear height for an egress door.

6’-8” is the minimum headroom height in a stairway (so if you can get through a 6’-6” height for a door why the need for an extra 2” for the stair?).

7’-0” is the minimum clear height for a habitable room (non-habitable rooms such as the powder room, bathroom and laundry room can be 6’-8”). They may want to rethink that bathroom height I have seen people spend an incredible amount of time in there to the point where they can claim squatter’s rights!

12’-3” is the maximum run for a stair before a landing is required (in case you were wondering if you used the maximum riser that would be 18 steps until you are required to rest)

60’-0” is covered in Table R302.2(3) Height and Exposure and Adjustment coefficients for Table R301.2(2), just in case if you thought I made that number up!

This is just a small sampling of the vertical dimensions in this 44 page long chapter and does not even consider width or thickness. I wonder why the IRC is 674 pages long. Have you been “enheightened”?