Need Advice on Basement Stairs

6 years ago

last modified: 6 years ago

Hello,

We are remodeling our lower level and replacing the straight staircase. The original staircase is 36" wide, up against a wall and open tread with no nosing, 9" treads, a 7.75" rise, and a 42" landing. The stringers and treads are both carpeted and we want to add risers, add 1" nosing to a 9" tread, paint the stringers, and carpet the steps. When we took the carpet off the stringers they were in terrible condition, hence the desire to replace the whole staircase.

We wanted the same dimensions with risers and a 1" nosing added to the tread. When the contractor built the staircase, he built it with 9" treads and 1.5" nosing (total tread depth 10.5"), 7.75" risers, and a 29" landing. Obviously this wasn't ok so he tried to "fix" it by reducing the top step to an 8" tread with a 1.25" nose (total tread depth 9.25") and he left the rest of the treads/nosing the same. He then reduced the bottom of the stringer such that the distance from the bottom tread to the end of the stringer is 1/16", which is not going to work with 1/2" thick carpet. And for some reason the top step now has an 8" rise instead of a 7.75" rise. There is now a 38" landing.

I am quite sure the top tread is not to code but he is arguing it is, they are fine, they don't need to be rebuilt, is refusing to rebuild them, and demanding payment. He said they can not be built with the same dimensions because there are code restrictions on how close you can move a tread forward to the edge of the stringer (but 1/16" is ok on the bottom step?). The code in our area follows the 2018 Residential Code of Ohio which requires a 9" tread plus requires a nosing of no less than .75" (unless the tread is 11" to begin with) for a total tread depth of 9.75".

I just want to make sure we are not missing something here - does this sound right? I know it doesn't feel right!

Featured Answer

PRO

PPF.

6 years ago

It's not right.

The code requires a minimum 9" tread.

311.7.4 Stair treads and risers.

Stair treads and risers shall meet the

requirements of this section. For the purposes of this section all dimensions

and dimensioned surfaces shall be exclusive of carpets, rugs or runners.

311.7.4.1 Riser height. The maximum riser height shall be 8 ¼ inches

(196 mm). The riser shall be measured vertically between leading edges of

the adjacent treads. The greatest riser height within any flight of stairs

shall not exceed the smallest by more than 3

/8 inch (9.5 mm).

311.7.4.2 Tread depth. The minimum tread depth shall be 9 inches (254

mm). 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. The greatest tread depth within any flight of stairs

shall not exceed the smallest by more than 3

/8 inch (9.5 mm). Consistently

shaped winders at the walkline shall be allowed within the same flight of

stairs as rectangular treads and do not have to be within 3

/8 inch (9.5 mm)

of the rectangular tread depth.

Winder treads shall have a minimum tread depth of 9 10 inches (254 mm)

measured between the vertical planes of the foremost projection of

adjacent treads at the intersections with the walkline. Winder treads shall

have a minimum tread depth of 6 inches (152 mm) at any point within the

clear width of the stair. Within any flight of stairs, the largest winder tread

depth at the walkline shall not exceed the smallest winder tread by more

than 3

/8 inch (9.5 mm).

311.7.4.3 Profile. The radius of curvature at the nosing shall be no greater

than 9

/16 inch (14 mm). A nosing not less than ¾ inch (19 mm) but not

more than 1¼ inches (32 mm) shall be provided on stairways with solid

risers. The greatest nosing projection shall not exceed the smallest nosing

projection by more than 3

/8 inch (9.5 mm) between two stories, including

the nosing at the level of floors and landings. Beveling of nosings shall not

exceed ½ inch (12.7 mm). Risers shall be vertical or sloped under the tread

above from the underside of the nosing above at an angle not more than 30

degrees (0.51 rad) from the vertical. Open risers are permitted, provided

that the opening between treads does not permit the passage of a 4-inch

diameter (102 mm) sphere.

Exceptions:

4101:8-3-01 58

1. A nosing is not required where the tread depth is a minimum of

11 inches (279 mm).

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Comments (7)

PRO
PPF.
6 years ago
does this sound right?

Does what sound right? You seem to have left out part of the story, or added in extra ...
HU-642505631
Original Author
6 years ago
The top step is an 8" tread with a 1.25" nose. The following steps are 9" treads with 1.5" noses. Does it sound right to have treads of different dimensions in the same staircase?
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HU-642505631
Original Author
6 years ago
Thank you. I didn't think it was right, but I'm not a professional!
PRO
Summit Studio Architects
6 years ago
Actually, the maximum riser allowed by the International Building Code is 7 3/4" for residential construction. Minimum tread depth is 10". You will also need 6'-8" headroom.

The Stair Manufacturer's Association has a great visual guide that shows all the code requirement you will need to meet. The free version from 2006 is still relevant, or you can purchase a more recent version.
User
6 years ago
last modified: 6 years ago
PPF was quoting the Residential Code of Ohio which applies to this stair. It is the 2018 IRC with certain amendments. These amendments happen to be the same in Massachusetts.

Here is the current version:

I have a question. Does the upper landing have a door that swings over it or not?

If it does, the landing must be 36" in the direction of travel. If it doesn't a landing is not required.

It usually helps to provide a photo or a drawing when discussing stair designs.
PRO
Summit Studio Architects
6 years ago
Aha! I missed the part about Ohio.