code for minimum floor space at top of stairs?

Can anyone tell me the distance required by code for floorspace at the top of a flight of basement stairs at a back entry. I am about to install a set and floor space is at a premium so I want to keep it to minimum code allowances.
thanks Aulden


I’ve attached a diagram for stairway code reference, but I hardly ever find basement stairs built to code. I find myself bending down many times to avoid hitting my head. New Construction would be a different story, but those older homes have the most dangerous stairs I’ve ever encountered.

“Click to Enlarge”

Thanks David,
That is what I thought. By the way, how do you guys find these photos so fast? You must be very organized!

I purchased and carefully organized the Carson & Dunlop Illustrated CD. They categorize the CD by numbers and index, so I had to go through every single illustration and rename my own categories. It took me weeks.


The Ontario Building Code 9.8.3. gives you all that info.

David is correct the only difference here in Ontario the headroom min. is 6’5".

Landings shall be at least as wide and as long as the width of stairs in which they occur.

Thanks David and Mario,
I have that CD and thought about it when I saw the pic. I may spend some time doing that as well. I wasn’t sure I could but I guess that is what I paid $500.00 for.
See you at the conference

Is that because Canadians are shorter than Americans?

Could be!!

What do you mean by “shorter”??:twisted: :twisted:

Some things to consider:

{NOTE: The items in the black font were in my original post. The items in the “Blue Font” were just added. I hope that some of this informations is helpful to you and to others on this BB.}

2006 International Residential Code for One and Two Family Dwellings
R303.6 Stairway illumination.
All interior and exterior stairways shall be provided with a means to illuminate the stairs, including the landings and treads. Interior stairways shall be provided with an artificial light source located in the immediate vicinity of each landing of the stairway. For interior stairs the artificial light sources shall be capable of illuminating treads and landings to levels not less than 1 foot-candle (11 lux) measured at the center of treads and landings. Exterior stairways shall be provided with an artificial light source located in the immediate vicinity of the top landing of the stairway. Exterior stairways providing access to a basement from the outside grade level shall be provided with an artificial light source located in the immediate vicinity of the bottom landing of the stairway.
Exception: An artificial light source is not required at the top and bottom landing, provided an artificial light source is located directly over each stairway section.

R311.5.3.1 Riser height.
The maximum riser height shall be 7¾ 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).

R311.5.3.2 Tread depth.
The minimum tread depth shall be 10 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). Winder treads shall have a minimum tread depth of 10 inches (254 mm) measured as above at a point 12 inches (305 mm) from the side where the treads are narrower. Winder treads shall have a minimum tread depth of 6 inches (152 mm) at any point. Within any flight of stairs, the largest winder tread depth at the 12 inch (305 mm) walk line shall not exceed the smallest by more than 3/8 inch (9.5 mm).

R311.5.3.3 Profile.
The radius of curvature at the leading edge of the tread shall be no greater than 9/16 inch (14 mm). A nosing not less than ¾ inch (19 mm) but not more than 1¼ inch (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 nosing shall not exceed ½ inch (12.7 mm). Risers shall be vertical or sloped from the underside of the leading edge of the tread 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.

  1. A nosing is not required where the tread depth is a minimum of 11 inches (279 mm).
  2. The opening between adjacent treads is not limited on stairs with a total rise of 30 inches (762 mm) or less.

R311.5.4 Landings for stairways.
There shall be a floor or landing at the top and bottom of each stairway.
Exception: A floor or landing is not required at the top of an interior flight of stairs, including stairs in an enclosed garage, provided a door does not swing over the stairs.
A flight of stairs shall not have a vertical rise larger than 12 feet (3658 mm) between floor levels or landings.
The width of each landing shall not be less than the width of the stairway served. Every landing shall have a minimum dimension of 36 inches (914 mm) measured in the direction of travel.

R311.5.5 Stairway walking surface.
The walking surface of treads and landings of stairways shall be sloped no steeper than one unit vertical in 48 inches horizontal (2-percent slope).

R311.5.6 Handrails.
Handrails shall be provided on at least one side of each continuous run of treads or flight with four or more risers.

R311.5.6.1 Height.
Handrail height, measured vertically from the sloped plane adjoining the tread nosing, or finish surface of ramp slope, shall be not less than 34 inches (864 mm) and not more than 38 inches (965 mm).

R311.5.6.2 Continuity.
Handrails for stairways shall be continuous for the full length of the flight, from a point directly above the top riser of the flight to a point directly above the lowest riser of the flight. Handrail ends shall be returned or shall terminate in newel posts or safety terminals. Handrails adjacent to a wall shall have a space of not less than 1½ inch (38 mm) between the wall and the handrails.

  1. Handrails shall be permitted to be interrupted by a newel post at the turn.
  2. The use of a volute, turnout, starting easing or starting newel shall be allowed over the lowest tread.

R311.5.6.3 Handrail grip size.
All required handrails shall be of one of the following types or provide equivalent grasp ability.

  1. Type I. Handrails with a circular cross section shall have an outside diameter of at least 1¼ inches (32 mm) and not greater than 2 inches (51 mm). If the handrail is not circular it shall have a perimeter dimension of at least 4 inches (102 mm) and not greater than 6¼ inches (160 mm) with a maximum cross section of dimension of 2¼ inches(57 mm).
  2. Type II. Handrails with a perimeter greater than 6¼ inches (160 mm) shall provide a graspable finger recess area on both sides of the profile. The finger recess shall begin within a distance of ¾ inch (19 mm) measured vertically from the tallest portion of the profile and achieve a depth of at least 5/16 inch (8 mm) within 7/8 inch (22 mm) below the widest portion of the profile. This required depth shall continue for at least 3/8 inch (10 mm) to a level that is not less than 1¾ inches (45 mm) below the tallest portion of the profile. The minimum width of the handrail above the recess shall be 1¼ inches (32 mm) to a maximum of 2¾inches (70 mm). Edges shall have a minimum radius of 0.01 inch (0.25 mm).

AJ501.8 Stairs.
AJ501.8.1 Stair width.
Existing basement stairs and handrails not otherwise being altered or modified shall be permitted to maintain their current clear width at, above, and below existing handrails.

AJ501.8.2 Stair headroom.
Headroom height on existing basement stairs being altered or modified shall not be reduced below the existing stairway finished headroom. Existing basement stairs not otherwise being altered shall be permitted to maintain the current finished headroom.

AJ501.8.3 Stair landing.
Landings serving existing basement stairs being altered or modified shall not be reduced below the existing stairway landing depth and width. Existing basement stairs not otherwise being altered shall be permitted to maintain the current landing depth and width.

R602.8 Fireblocking required.
Fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) and to form an effective fire barrier between stories, and between a top story and the roof space. Fireblocking shall be provided in wood-frame construction in the following locations.
[FONT=Arial]1. [/FONT]In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs; as follows:
{3. } in concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R311.2.2.
*{R311.2.2 Under stair protection. Enclosed accessible space under stairs shall have walls, under stair surface and any soffits protected on the enclosed side with ½-inch (13 mm) gypsum board.} *

R703.8 Flashing.
Approved corrosion-resistant flashing shall be applied shingle-fashion in such a manner to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. The flashing shall extend to the surface of the exterior wall finish. Approved corrosion-resistant flashings shall be installed at all of the following locations:

[FONT=Arial]5. [/FONT]Where exterior porches, decks or stairs attach to a wall or floor assembly of wood-frame construction.

E3504.1 Clearances on buildings.
Open conductors and multiconductor cables without an overall outer jacket shall have a clearance of not less than 3 feet (914 mm) from the sides of doors, porches, decks, stairs, ladders, fire escapes and balconies, and from the sides and bottom of windows that open. See Figure E3504.1.

Hellofajob Frank. Why do you bother knowing all this code information, we don’t inspect for codes do we?:twisted: Just kidding the more we know, the quicker we access it, the better we can serve our client. Looks like our fellow inspector needs a door which swings out as you go up the stairs to the landing.

As a Code Compliance Inspector, Technical Consultant and as a recognized Expert Witness, I receive a hefty salary for being able to provide this type of information to my clients.
I am happy to provide the service for free for my fellow NACHI members.

I hope that some of you find this information useful and will be able to add it to your database for future reference


Keep up the good work!!