020205a - Single-Flight Straight Stairs Flashcards
What is rise?
The vertical measurement or height from FINISHED FLOOR to FINISHED FLOOR.
What is unit rise?
The vertical rise measurement of each step. Unit rise is determined by dividing the rise by the desired number of risers.
What is run?
The horizontal distance covered by a stair, from the edge of the top step to the edge of the bottom step.
What are treads?
The horizontal member if a stair on which people place their feet.
What is a riser?
The vertical members of a stair placed behind treads that close the space between the treads.
What is a stringer?
The angular supporting members of a stair to which the treads and risers are fastened.
What is effective depth?
A measurement made at right angles to the slope of the stair from the rear junction of the riser and tread to the underside of a noticed stringer. The is the weakest section of the stringer.
What is stair flight?
A continuous series of steps with no intermediate landings.
What is line of flight?
An imaginary line that intersects the outer edges of all the nosings.
What is headroom in regard to stair framing?
The clear distance measured vertically from the line of flight to any obstruction above.
What is a stairwell?
The opening through which a stair will pass. This includes the opening in the floor frame as well as the surrounding walls.
What does finished opening dimensions mean in regard to stairs?
The horizontal, width, and length measurements of a stairwell, after all finishes have been applied and the stairs installed.
What does the rough opening refer to in regards to stair framing?
The horizontal, width and length measurements of the floor frame members around a stairwell opening before any finishes have been applied or stairs are installed.
What is a landing? in regards to stair framing
The platform or level floor area at the top, or bottom of a flight of stairs. May also be an intermediate level platform within a straight flight or at a position where two stair flights change direction.
What are some dangers associated with irregularities in either the unit rise or unit run of a stair?
tripping, loss of balance or falls.
What is the maximum and minimum unit rise for stairs?
The maximum is 200 mm and the minimum is 125 mm.
What is the maximum and minimum unit run for stairs?
The maximum is 355 mm and the minimum is 210mm.
Using a unit run at or near the minimum creates a steep stair. T or F
T
Most documentation recommends a stair slope of between 30 and 35 degrees. T or F
T
What is the highest slope by code for a stair?
43.6 degrees
What is the lowest slope by code for a stair?
19.4 degrees
What is the minimum tread width for a stair?
235
Nosings may be bevelled or rounded over. T or F
T. As long as the minimum tread depth is not reduced by more than 14 mm. Regardless of the tread width or thickness, the curve or bevel should not reduce the effective tread by more than 25 mm.
The leading edge of the tread (nosing) may not project more than __ mm beyond the face of the riser.
25 mm (1”)
Headroom clearance is measured from the flat surface of the tread. T or F
F. It is measured from the line of flight.
What is minimum clear height above any part of the line of flight to any overhead obstruction?
1950 mm and the full width of the stairs.
What is the minimum width between wall faces in a stairway?
860 mm. This is not recommended. Too small.
If a door is located at the top or bottom of a flight of stairs and swings towards the stairs, what is the condition?
That the full of arc its swing should be over a landing.
If the door swings aways from the stairs, a landing is not required between the door and the stairs. T or F
T at the top
What is the maximum vertical rise for a single flight stair is ___.
3700 mm. If the floor to floor measurement exceeds 3700 mm, a landing must be provided.
The effective depth of a botched stringer must be at least __ mm.
90 mm (3-1/2”)
Stringers must be from at least 38 mm x 235 mm (2x10) material. T or F
T
When would one use mitred stringers?
If one or both sides of stairs are exposed.
What is a housed stringer?
Stringers which are routered out to receive the treads and risers.
A handrail is required on at least one side of stairs less than ____ mm in width.
1100mm
A handrail is required on both sides of stairs if the width is 1100 mm or more. T or F
T
What is the maximum and minimum height above the line of flight for a hand rail?
MAX: 965 mm
MIN: 800 mm
Handrails should be attached to the walls with a minimum clearance of __ mm between the handrail and wall.
50 mm
The maximum projection into the required width of a stairway for a handrail is ___ mm.
100 mm
If an interior stair, including landings, is open on one or both sides, protection from falling must be provided. T or F
T
Guards may be omitted for stairs if the rise of the stair is ___ mm or less.
600 mm (24”)
Stairs to unfinished basements do not require guards. T or F
T
If guards are constructed with vertical spindles, they should not be spaced more than ___ mm apart.
100 mm (4”)
Any feature that would allow climbing is not allowed for a guard rail. T or F
T
A unit rise of approximately 180 mm or 7-1/8” is traditionally considered a good unit rise. T or F
T
What is head allowance?
Allowance for the attachment of the top of the stairs to the header joist.
The minimum head allowance that should be allowed is for the nosing and the thickness of the riser material. T or F
T
A semi-housed stringer consists of two separate stringers, what are they?
a notched (cut-out) stringer and a backing (supporting) stringer.
Backing stringers are usually made of __ mm thick material.
38 mm