lecture 9 Flashcards
tread
horizontal surface of a stair that we walk on
riser
vertical component of a stair that separates one tread from another
what is nosing
the front edge of a tread that overhands the riser
whereare railings required?
required on both sides of the stairs
when do you need a landing with stairs?
if our stairs change direction and every 12’
what are the key elements of a stair
tread
riser
nosing
railings
landings
what is the ratio of rise to run in a typical stair
(2) risers + (1) tread= 24” to 25”
6 1/2” -7” risers and 11” treads are very commonly used in REZ construction
tread depth
10” min for rez
11” min for commercial
riser height
between 4”-7 3/4” for rez
between 4-7” for commercial
nosing overhang
is between 3/4- 1 1/4” for rez
minimum stair width
36” in a single family rez
44” everywhere else
what is the max rise of a stair before the landing is required?
12’
what is the mim head clearance between a tread and the projection of a tread
80”
6’8”
landing must be how wide
at least the width of the stairs
striaght run stair
a stair that extends from one level to another without turns or winders
how can a stair be turned?
quarter-turn stairs
half-turn stairs
winding stairs
quarter-turn stairs
a stair that turns 90 degrees or that is L-shaped plan
half-turn stairs
a stair that turns 180 degrees or that is U-shaped in plan
winding stair
a stair that turns in some configuration using winders to create a circular stair @ the point of rotaion
how can a stair sit in the round
circular stair
spiral stairs
spiral stair
wedge-shaped treads that wind around a central post
what is the difference between a handrail and a guardrail?
handrail= is present to assist a user in safely navigating the stairway- it is what IS HELD ON TO
guardrail= is present to keep a user from FALLING off the stairway- it is like a BARRICADE
guardrail height
42” min off the treads
handrail height
34 - 38” off the tread
handrail diameter
1 1/4 - 2”
handrail clearance
1 1/2” min to the wall
what is the general construction of a stair
carniage
ledger
stringer
cariage
inclined beams that act as a structual element of the stairs that span from floor to floor and support the treads
(also called rough stringers)
ledger
a member that provides support for the carriages
(can be substituted with a joist hanger)
stringer
sloped finish member running along the side of a staircase against which the risers and treads terminate
open riser stair
a stair with voids at the riser condition so you can see through to below
what is the max opening for a open riser stair
maximum of a 4” space between the treads
what is the typical configuration of an accessible ramp
1:12= max slope
36”= min width of a ramp
30” the max rise of the ramp before you need a landing
60”= the min length of a landing
what does 1:12 mean with ramps
a 1” rise for ever 12” of run
what is the last ratio that is still considered to be a ramp rather than a sloped walk
1:20
how large does the landing need to be? where does it go?
60” is the minimum length of a landing at each end of the ramp or when it changed direction
hnadrail height for a ramp
4’ min height
ANYTHING above _” rise requires a handrail for a ramp
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