H-5 Stairs Flashcards
?
2 Rise Straight Gooseneck
where do the wedges go on a Stringer?
what type of Stringer
?
Starting Easing with Cap
info
?
2 Rise Straight Gooseneck with Tandem Cap
On a Dadoed Stringer , how deep the is the dado
?
Tandem Cap
Fillets are where in a stair system
shaped to fit between balusters under the handrail and on top of buttress cap
?
Right Hand Volute
?
Mitred stringer
?
Notched stringer
A balusters must have max opening between of opening?
100mm
A primary stairway between each floor in a dwelling unit must have a minimum between wall of faces what’s that distance
860 mm
A semi-housed or planted stringer has two parts:
A cut out stringer and a plain stringer. The plain stringer is a finished piece of wood attached to the wall. The cut out stringer is laminated to the plain stringer. The treads and the risers butt into the finished plain stringer.
a starting newel should
be extended into the flooring system, use dry material
anchorage
important to anchor posts securely in place. to support weight of people always grabbing them, starting newel should be extended through floor and securely blocked
Are handrails required when there’s only two risers within a dwelling unit
No
Balusters
small uprights under the handrail that close in the open side of the stairs for safety
building code requires balusters to be spaced such that a 4” diameter object cannot fit through it.
balustrade
complete unit of newel posts, handrail, balusters and buttress cap used to protect open side of staircases
buttress or string cap
used under balusters also called shoe rails or base rails
shaped to take the end of the baluster and are used in railings at the landings or on top of the stringers.
calculate stairwell rough opening
RO = run/rise x (headroom+floorthickness) + 75mm
Calculating stringer length
three methods
- multiply unit of bridge by number of treads
- multiply unit of bridge by number of rises
- number of linerier feet of stringer is equal to the number of treads (allow extra foot)
Calculating actual Rise
take total number of risers and divid by the total rise
Ex 2650/15=176.67mm or 177
Calculating run
using proportion rules the run can be calculated
- rise plus run = 450mm
rise= 177
177 + X=450
X=450-177
X(run)= 273mm
Circular stairs can be built from
Wood, concrete or steel
closed stairs
enclosed on both sides of stairway, handrail is attached to wall
Define double L stairs
A straight flight of stairs, with only 2-3 treads at right angle of main stairs at both top and bottom
Define wide L stairs
Consists of two straight flights at the right angles to each other
Define wide U stairs
They have 3 flights of stairs separated by 2 landings
Desired rise
use 7”
Does a Narrow u have steps in have steps in the landing on the back wall
double L stairs
straight flight with two or three treads at right angles to the main stairs.
Exterior concrete stairs
with more then two risers and two treads stairs must be supported on proper foundations that extend to firm bearing below frost heave. or hang stairs off main foundation wall as long as its 200mm thick (8”)
finished opening
horizontal distance from edge of the nosing at the upper landing to the opening edge of the finish at the other end of the stairwell
First step to layout the stringer ?
Plumb cut
for dadoed stringers, what is the depth of the dadoed notch?
for dadoed stringers, what is the depth of the dadoed notch?
Guards are how high of the landing surface?
1070mm above the landing and within a dwelling unit, guards can be 900mm high.
Guards for handrails code
are set at least 1070mm (42”) above landing surface 920mm (36”) above nosing line.guards must not be able to fit babies heads (100mm or 4”)
handrail
form the rail between newel posts
- meterial used must be graspable
- must be at least 2” clearance between handrail and wall
Handrail brackets must be spaced o/c max on a handrail?
1.2m
Handrail Heights on stairs and ramps must be between
865 mm and 1007 mm
Handrails are usually with a clear of how much from the inside of the rail to the wall?
50MM
Ergonomic Design
1) The clearance between a handrail and the surface behind it shall be not less than
a) 50 mm, or
b) where said surface is rough or abrasive, 60 mm.
2) All handrails shall be constructed so as to be continually graspable along their entire length
with no
obs ruction on or above them to break a handhold. (See Note A-9.8.7.5.(2).)
https://free.bcpublications.ca/civix/document/id/public/bcbc2018/bcbc_2018dbp9s98
handrails codes
required for all stairs more then two risers ( interior) and more then three exterior
Headroom
vertical distance from nosing line to underside of floor above
headroom
minimum headroom is measured vertically from nosing line to bottom of finished opening floor. must be at least 1950mm (77”) within dwelling units and 2050mm (80”) for all other stairs
How are curved stringers usually made?
Manufactured in a stair building plant using curved walls to form a jig and shipped to the job site.
How deep are the gains on a housed stringer?
about 1/2
How do you determine the number of risers?
Divided by the total rise by the desired rise. The fraction is rounded up if the decimal fraction is over point five. .05 and lower is always rounded down
how do you get rise per step?
after you have number of risers, divide number of risers by total rise for the rise per step
(2650mm/15=176.667mm) Rise per step= 177mm, round to the nearest millimetre
How is a housed stringer made?
Special adjustable templates are commercially available or a template can be made for the rise and run of the stair, which includes an allowanced for wedges to tighten the treads and the risers in place.Router is then used with the template to cut a gain (Recess) into the side of the stringers.
How is the floor thickness calculated?
Sum of ceiling finish + joist depth + subfloor thickness + finished flooring
How is the height of handrails measured?
vertically from the nosing line.
How many handrails are required if the dwelling unit stairwell is less than a 1100mm wide
It must have a handrail on one side
how many landings in a narrow “U” stairs?
how many flights of stairs in a wide “U” stairs?
- two landings for “U’
- three staircases in a wide “U”, two landings still
how to find total number of risers
total rise divided by the desired rise
- then round off because you cannot have partial step
Example:
total rise= 2650mm
desired rise = 180mm
2650/180= 14 .72 risers OR 15 risers
If you add the finished floor after you make your stairs what calculation must be done ?
Unit of rise - thickness of tread + finished floor
Improperly design stairs are problem and what matter
Tripping hazard
Is 180 mm rise and a 250 mm run good?
It’s the most comfortable 7 by 10
Know the following terms
total rise
total run
unit rise
unit run
tread
riser
nosing
nosing line ( Unit of bridge)
Tread depth
Headroom
finished opening
rough opening
stringer support board
stringer
You know these boys pg 3-4 H-5 LT1
L SHAPED WITH LANDING OPEN STAIRWELL LOOK LIKE
landings
used to change direction of stairs or break up total rise
- BCBC requires landings every 3.7 m vertically
Landings
- used to change directions in stairs
- or to break up total rise to create shorter flights of stairs
BCBC allows max total rise between landings to be 3.7 meters OR 2.4 meters for group B occupancy (hospitals etc…)
?
Right Hand Volute?
long L stairs
consists of straight flight, with two or three treads at the top or bottom at right angle to main stairs .
Lubmer stringers
must be at least 225mm wide (9 1/4”) and have effective depth after cutting out rise and run of at least 90mm (3.5”) but be supported and secured at both top and bottom.
Materials used in a handrail must be?
graspable
max spacing of stringers
2’ OC for public stairs
3’ for stairs serving single dwelling units
minimum rise for private ad public stairs according to BCBC
public: max 180mm (7”) min 125 (5”)
private: max 200 (8”) min: 125mm (5”)
Minimum size of wooden stringer ?
2x10
although 2x12 is safer
Mono Stringers
Mouldings
used to trim under nosing to finish stairs cove or crown mouldings normally used
narrow U stairs
have two flights of stairs running opposite directions with a landing at the midway point.
Newel Posts
are the main supporting the balustrade
- starting newel used at bottom
- angel newel used at turn of stair
- landing newel used at top
nosing
projection of tread beyond face of riser board.
- BCBC requires maximum extensions of 25mm (1”)
- must be chamfered or rounded
-
nosing line
imaginary line drawn above top edge of nosing
nosing returns
when stringer and riser have both been miter. exposed end of tread is shaped in the same way as the front nosing.
Nosing returns are used when
The stringer and riser have both been mitered
On a closed starwell what does a stight run look like
open stairs
have one or both sides open to a room or hallway. all open stairs have balustrade
OPEN STAIRWELL what does a double L look like ?
the minimum headroom measured from vertically from the nose and line must be at least
1950 mm stairs located within a dwelling 2050 mm for all other stairs
preferred angle of stairs
in between 30°-35°
10 and 7 stair has 35°