Stair Tread Specifications & Defects The stair treads shown in our photo are very dangerous not only because they are pitched and loose, but because there is danger of stairway collapse. The stair inspector should be asking: "What caused this weird movement and who made these goofy repairs?" Stair Step Treads Step tread depth (=> 10") (measured 12" from smaller side of irregular stair shapes such as triangular treads on curves or spirals) Step tread depth uniformity (<= 3/8" variation) Stair tread depth for winder stairs (>= 6" at smallest point) Stair tread uniformity for winder stairs at the 12" walk-line (<= 3/8" variation) Stair tread slope (out of level on walking surface) - (slope or "rise" must be <= 1 in 48) -- Source: IRC
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Stair Tread Specifications & Defects
The stair treads shown in our photo are very dangerous not only because they are pitched and
loose, but because there is danger of stairway collapse.
The stair inspector should be asking: "What caused this weird movement and who made these
goofy repairs?"
Stair Step Treads
Step tread depth (=> 10") (measured 12" from smaller side of irregular stair shapes such
as triangular treads on curves or spirals)
Step tread depth uniformity (<= 3/8" variation)
Stair tread depth for winder stairs (>= 6" at smallest point)
Stair tread uniformity for winder stairs at the 12" walk-line (<= 3/8" variation)
Stair tread slope (out of level on walking surface) - (slope or "rise" must be <= 1 in 48) --
Definition of stair risers: a stair riser is the vertical space between stair treads (treads are what
you step on). If the vertical space is enclosed (see our drawing at page top), the enclosing board
is called the stair riser. If the vertical space between stair treads is open (see our photo at left) the
space is still a stair riser, but it's an "open riser".
Open stair risers with a more than 4-inch opening are e a child hazard, as we detail below.
Stair risers, or the vertical distance between the stair treads, that are too tall are difficult to climb
and are a falling or trip hazard.
Stair risers that are too short can also be a trip hazard if the stair treads themselves (the walking
surface of the stair or step) are not large enough. As we discuss below, generally as we reduce
the stair riser height below about 6-inches, we need to increase the "depth" (front to back
distance) of the stair tread.
Stair risers that are uneven or irregular in height are also a serious trip and fall hazard. That's
because when people walk up and down stairs we are mostly on "auto pilot" - our brains assume
that each step height will be the same as the one we took just before. So a "surprise" such as a
step that is taller or shorter, can make us fall - a particular hazard for the elderly, children, or
people who are physically disabled and have trouble climbing stairs. (Also see ELDERLY &
VETERANS HOME SAFETY).
Step riser specifications riser height (<= 7.75") - this means you rstair risers should be less than or equal to 7 3/4 inches. No taller. Some codes specify slightly taller stair risers, from 8" to 8 1/4" (Canada, for example).
Step riser height uniformity (<= 3/8" variation) - this means that more than 3/8 of an inch in variation of the height of steps from one step to another is a tripping hazard.
Step riser slope (out of vertical) (<= 30 deg measured from horizontal surface of the tread) - this stair specification means the rather obvious hazard that if stairs are pitched or sloped users are more likely to trip and fall. Outdoor stairs that are exposed to wet or icy conditions are an even more serious falling hazard if the stairs are sloped.
Step stair riser openings: open stair risers are permitted provided the opening will not pass a 4" sphere (child safety). This 4-inch opening dimension has the same basis as the rule that requires that the opening between stair balusters must be 4" or smaller.
Stair Riser Defects
As we explained just above, the most common stair riser defects likely to lead to a fall include:
Stair risers of uneven height - no variation greater than 0.375 inches is allowed Stair risers of improper height, too tall Stair risers of improper height, too short
Bad Deck Stair Example:
Nothing is right about the exterior stairs shown in our photo (above) from a 1991 home
inspection:
This stair stringer is too-deeply notched and could split; The stair risers are too high, as our client is showing with our tape. The stair treads are too narrow. There is no railing and the height above ground is more than 36". The deck and platform railing is open with no balusters.
See Deck & Porch Steps or Stairs for more details.
Summarizing proper stair dimensions for Closed Riser Stairs
Closed riser stairs include a board or other solid material that encloses the vertical space
between stair treads.
Stair riser height: ideal: 7 3/4, or in some jurisdictions 8 to 8 1/4" tall. Some older homes include a very steep stairway to access the home's attic. The stairs were very tall or "steep" when there was simply not enough horizontal space for a longer and less steep stairway. It may be impractical to fix this condition by a new stairway for the same reason - there just isn't enough space. Be sure to reduce the falling hazard at steep stairs by providing good lighting and secure handrails. (See Attic stairs)
Stair tread nosing: required, 1" to 1 1/2" projection beyond the riser face Stair tread run (or horizontal depth): 8 1/4 to 9" Stair tread thickness: 1" or greater, tread is supported by the riser.
Summarizing proper stair dimensions for Open Riser Stairs
Open riser stairs do not include a solid board or other material that fully encloses the open space
between stair treads (see the sketch above).
Open riser stair treads should be to 9 1/4" in depth and will typically be greater at shorter stair riser heights.
Open riser stair treads must be at least 1 1/2" thick because the tread, not supported by a riser, may otherwise split.
Open riser stairs are allowed a"back slope of at most 1 1/2". Take a look at the sketch above. Because there is no solid vertical riser to enclose the space between stair treads, the concept of a stair tread "nose" does not apply. But if stair treads are constructed so that the front edge of a tread is more than 1 1/2" behind the back edge of the stair tread below, the treads can become a trip hazard.
See these detailed articles on the proper dimensions for safe stairs and steps:
Stair dimensions: width height &c
Stairway headroom
Stairway landings
Step riser dimensions
Step stringer defects
Step tread dimensions
Stair tread nose dimensions
Rules for Constructing Stairs that are Curved or Angled, &
My daughter fell down curved stairs at a shopping mall where the triangular tread hazard was
combined with a beautiful, architect-designed handrail that was about 8" in diameter - she was
unable to grasp it as she was falling.
The photo shows her sister grasping n added handrail that was welded on to correct this unsafe
condition.
The original "fat" hand railing that no one could grasp when falling is along the diagonal-right
side of the photo. From: http://www.inspectapedia.com/interiors/Stair_Risers.htm
Need to Measure your Stairs ?
When it comes to measuring your new staircase it is important that you get the correct measurements , use this guide to help you understand the measurements we require to calculate your new staircase.
RISE For a straight staircase measure your rise measurement first, this is the distance from the finished floor
level where the staircase starts to the finished floor level on the upper floor where the staircase is going to. If your floors are slightly out of level the make sure you get your rise from the points where the staircase is going to sit.
GOING
Once you have your rise you can work out the going distance (Dimension G)for the stairs this is the distance the staircase will project along the floor, look at our rise and go chart to see the correct going to suit your rise height when trying to achieve a 42 degree pitch.
WIDTH
If you are measuring a staircase for between walls make sure you measure the narrowest point and allow a clearance, this is OK if the staircase is assembled and the staircase can slide into place without having to be turned in the hole (between the walls) and is also OK if the staircase is ordered flatpack for assembly in situ between the walls, but if your staircase is going to need turning in between the walls you need to allow more clearance normally 75mm is OK but this needs checking before ordering, to work this out you need to draw a rectangle to scale (draw a rectangle the proposed width by 244mm which is the typical depth of the stair stringers we use and measure across the furthest points to check you can rotate the staircase) The width is also important when it comes to your landing room at the top and the bottom as this needs to be equal or more than the width of the staircase.
The width of a standard domestic staircase is 860mm over all the strings, the minimum width we would recommend for a Loft staircase is 600mm over all the strings.
If you are measuring a staircase which is to have handrails to one side and it is quite tight to the well hole you need to think about finger room between the handrail and the side of your stairwell the minimum clearance we recommend is 40mm this would mean you need to allow 55mm clearance on you over all string measurement from the finished well size.
New - Order a Straight flight online at Tradestairs.com
As with straight stairs start with your rise measurement and use the rise and go chart to work out the number of risers required and the going size your treads need to be to give you a 42 degree pitch, take
your going dimension G1 and work out haw many goings will fit and what width you are left with remember the width of a standard domestic staircase is 860mm, you will probable have 2 choices of rise heights to choose from eg :- 12 or 13 risers these will have different going sizes you need to choose the one that suits best, Your next size the G measurment is governed by the number of goings you need and the width of the staircase.
With a quarter landing staircase you will only need to allow the width of the staircase in the corner for your turn, with a winder staircase things get a little more complex. With the UK building regulations there are 2 important factors to remember ; -
1. Minimum 50mm Going - at the inside edge of your winder treads you must have a minimum going of 50mm, this means on a typical 860mm wide staircase with a standard 90mm newel post in the corner the typical area for a 3 tread winder corner increases by around 30mm so on a 860mm wide stair the typical winder box size is 890 x 890mm.
2. Winder Walk line Going - UK building regulations require the distance in the center of a winder tread to have a going no less than the going on the main part of the staircase, on staircases wider than 800mm Overall strings this is not normally an issue but on narrower staircases it is required to increase the winder box size by more than the 30mm as detailed above for the 50mm goings to achieve a walk line going that meets the requirements. EG - a 600mm wide staircase would need a winder box size of typically 750 x 750mm.
With half landing staircases and Double winder staircases all the perimeter dimensions are
9.8.4.1. Dimensions of Landings 1) Landings shall be at least as wide and as long as the width of stairs in which they occur,
except that
b) the length of landing for all other stairs in a straight run need not exceed 1100 mm.
(See also Articles 9.9.6.2. and 9.9.6.6. for landings in exits.)
9.8.4.2. Required Landings 1) Where a door swings towards a stair, the full arc of its swing shall be over a landing.
2) Except as provided in Sentence (3), a landing shall be provided at the top and bottom of each
flight of interior stairs and where a doorway occurs in a stairway. 3) Where a door at the top of a stair in a dwelling unit swings away from the stair, no landing is
required between the doorway and the stairs.
9.8.4.3. Height between Landings 1) The vertical height between any landings shall not exceed 3.7 m.
9.8.4.4 Height over Landings 1) The clear height over landings shall be not less than 1.95 m in dwelling units and 2.05 m for
other landings.
9.8.5. Curved Stairs and Winders
9.8.5.1. Curved Stairs in Exits 1) Curved stairs used in exits shall conform to the requirements of Article 3.4.6.8.
9.8.5.2. Curved Stairs not in Exits 1) Except as permitted in Article 9.8.5.3., a curved stair not required as an exit shall have an
average run of not less than 200 mm and a minimum run of 150 mm and shall have risers
conforming to Article 9.8.3.1.
9.8.7. Handrails
9.8.7.1. Required Handrails 1) Except as permitted in Sentences (2) and (3), a handrail shall be provided on
a) at least one side of stairs less than 1100 mm in width,
b) 2 sides of stairs 1 100 mm in width or greater, and
c) 2 sides of a curved stair used as an exit.
9.8.7.2. Continuous Handrail 1) At least one handrail shall be continuous throughout the length of the stairway, including
landings, except where interrupted by
a) doorways, or
b) newel posts at changes in direction.
(See A-3.4.6.4.(5) in Appendix A.)
9.8.7.3. Termination of Handrails 1) Handrails shall be terminated in a manner that will not obstruct pedestrian travel or create a
hazard. (See Appendix A.) 2) At least one handrail at the sides of a stairway or ramp shall extend horizontally not less than
300 mm beyond the top and bottom of the stairway or ramp. (See A-3.4.6.4.(5) in Appendix A.)
9.8.7.4. Height of Handrails 1) Height of handrails on stairs and ramps shall be measured vertically from a line drawn
a) through the outside edges of the stair nosing, or
b) from the surface of the ramp, floor or landing below the handrail.
2) Except as provided in Sentences (3) and (4), the height of handrails on stairs and ramps shall
be
a) not less than 800 mm, and
b) not more than 965 mm.
3) Where guards are required, handrails on landings are permitted to be not more than 1 070 mm
in height. 4) Handrails not meeting the requirements of Sentences (2) and (3) are permitted provided they
are installed in addition to the required handrails.
9.8.7.5. Ergonomic Design 1) A clearance of not less than 40 mm shall be provided between each handrail and the wall to
which it is fastened. 2) Required handrails shall be constructed so as to be continually graspable along their entire
length with no obstruction on or above them to break a handhold, except where the handrail is
interrupted by newels at changes in direction. (See Appendix A.)
9.8.7.6. Projections into Stairway 1) Handrails and constructions below handrails, including handrail supports and stair stringers,
shall not project more than 100 mm into the required width of a stairway.
9.8.7.8. Attachment of Handrails
(See Appendix A.)
1) Handrails shall be attached to wood studs, wood blocking, steel studs or masonry at points
spaced not more than 1.2 m apart. 2) Attachment to wood studs and blocking required in Sentence (1) shall consist of not less than
2 wood screws at each point, penetrating not less than 32 mm into solid wood.
From: http://www.amezz.com/cnbcstairref.html
Stair & Staircase Regulations
The most important dimension Pear Stairs need is a measurement from the Finished Floor to
Finished Floor. (See Home Page, "who measures your staircase").
flight with 180° turn: landing allows respite from climbing
Figure 12.1 C - Flight with 180° turn and winders
flight with 180° turn and winders: winders are not acceptable
Figure 12.2 - A long straight flight with a landing
handrails on one or both sides to suit users long straight flight with middle landing: allows users to rest halfway
The staircase will be safest if it:
is well lit, without glare provides a landing at the top and the bottom for the user to steady themselves before changing
direction has no doors that obstruct the top or bottom landings consists of more than one step.
Rather than allowing a small change in level that requires a single step, it is better to design the
floor surface to be level. If this is not possible, a small ramp is the best way to connect the two
levels.
Figures 12.3 and 12.4 illustrate the dimensions of a preferred stair.
Figure 12.3 - Principles of step design
treads large enough to provide adequat footing good slip resistance nosing projection round nose to reduce chance of toe catching preferably the riser should be modified by: insertion of timer fillet, carpeting, no open risers and
uniform riser height
Figure 12.4 - Step dimensions
going 250 to 265mm preferred 25mm maximum riser 170 to 180mm preferred tread
The dimensions do not replace those outlined in building regulations. Each step will be safest if
it has a:
comfortably sized tread slip resistant tread or nosing solid and non-transparent vertical back, or rise, so that nothing can get caught in between each
step nosing in a colour that contrasts with the rest of the tread and does not project more than
25mm, as illustrated in figure 12.3 treads and risers of consistent dimension throughout a flight.
Closed, opaque risers and colour contrasting nosings assist people with vision impairment. A
change of flooring surface and colour at the head and foot of a flight of stairs will also assist
people with vision impairment.
Stairs should be at least 850mm wide but around 1000mm is easier to negotiate. Stairs greater
than 1200mm wide can accommodate a stairlift as illustrated in figure 12.5.
Figure 12.5 - Width of a staircase
clear opening, 850mm minimum, 900mm preferred, 1200mm will allow easy movement of furniture and addition of a stair lift
handrail on one or both sides to suit the occupants' needs
Landings should be the same width as the stair and at least 850mm in length. Headroom must be
at least 2000mm measured from the line of the nosing as shown in figure 12.6.
Figure 12.6 - A straight flight of stairs
good general lighting consider recessed shelves at top and bottom of stairs if wall allows 2 way switch level handrail minimum headroom 2000mm for handrail configuration, see Figure 13.11 2 way light switch or sensor 300mm tread depth consider low level lights for step dimensions see Figure 13.6
Stairs must be fitted with a handrail on one side and for people with a preferred hand, handrails
may be needed on both sides. Handrails need to be placed so that:
they do not reduce the clear width of the stair they are between 865mm and 1000mm apart, and at a height that suits the intended user they are easy to grip they extend 300mm beyond the end of the flight of stairs, with a downward sloping end to
indicate to people with impaired vision that there are no more stairs
There are two different classes of stairs. The first class is a mill-made stair, which is usually
fabricated in a mill shop and shipped to the job site as a kit, ready for assembly and
installation. The second class, a carpenter-built stair, is just that — a stair built on site by a
carpenter. This type of fabrication is less expensive and allows the stair to be covered with
carpet. A carpenter-built stair can be dressed up with a hardwood or paint-grade skirt board. And simple wall-mounted railing is a popular option to complete either type of stair.
When constructing a stair, functionality is the most important consideration. Extreme
accuracy must be used for a safe design. Before beginning construction, you should consult
not only the national building-code requirements, but also the local building-code
requirements. Some municipalities have stricter codes than others, and checking first will eliminate the need to rebuild later.
Cutting the Stair
Now that we have directions on paper as to how to build our stair, it is time to begin cutting.
Carpenters always measure twice and cut once, a good rule to follow when cutting stairs. Stair
building can be expensive; you only want to purchase the materials once, so purchase and cut
wisely.
When you start the project, make sure your work area is clean and well lighted. Working in
comfortable surroundings makes a difficult task a little easier.
Lay out the stringers to begin the actual stair project. Do this by setting the rise and run of the
stair on the framing square. The framing square clamps should be adjusted to 7 3/8 inches by 10
inches. Next, mark off the number of treads and risers that are needed for this stair. Always start
with the first riser and end with the top riser, and draw in the second floor line. At this point it is
helpful to count the number of risers so there isn't a layout error. Repeat this procedure for all
three stringers.
After you have marked the treads and risers, it is time for the final adjustments to the stair
stringer. As with any well-planned work of art, tweaking the design may be necessary. In
order for all of the risers to be in code-compliance, adjusting the top and bottom risers may
be necessary. In our example when a 1-inch-thick tread will be added to the bottom tread
cut, our bottom riser will be 1 inch too high. The opposite is true at the top. When we add
the top tread, its thickness deducts 1 inch from the exposed riser height. To correct this
situation we will deduct 1 inch from the bottom riser cut at the floor-level portion of the stringer.
After you have successfully laid out the stringers, cut off the triangular portions. A power
saw is the best tool for this task, but be careful not to cut beyond your marked layout lines,
which will weaken your stringers. The final cutting of the triangles can be cut out with a
handsaw. After all three stringers are cut out, place them together to make sure they all
match. Three perfect matches are what you want to achieve. Anything less than three perfect stringers and you may want to consider going back to the drawing board.
With three good-looking stringers on your bench, you can now take the left and right
stringer and position them on top of the 1-by-12-inch skirt boards. On each skirt board,
trace the cut where the stringer meets the floor and the top riser. Cut these lines out and
also make a plumb cut on the bottom of this board at the height of the baseboard. Attach
the skirt boards to the two stringers. These two stringers are now finished and can be nailed
on top of the drywall. If no drywall is in place, fill out the stringers to the thickness of the
drywall. Always, always, nail or screw to the studs. The center stringer is now ready to be mounted to the top header and attached to the blocking at the floor.
Now that your stringers are in place, it is time to double-check all of your cuts. Check the tread
cuts for level and plumb. Check your measurements in every direction, left to right and front to
back. Check the top and bottom riser--does it allow for the finish tread height? The top riser
should offer a tread thickness of more than 7 3/8 inches and the bottom riser should be tread
thickness less.
If after you have double-checked all of your cuts, and you are satisfied that you're on the right
path, it is time to rip the risers to the correct heights and nail them into place. Don't forget to glue
and nail them for long-lasting durability. Your treads should be 11-1/4 inches so they will not
need to be ripped, just cut them to length, glue and nail into place.
Nail the treads and risers to the stringers. Install by nailing through the back of the risers and into
the treads, always using cement-coated fasteners.
Your stair is now complete except for the wall or handrail. Because our example stair is located
between two walls, we will need to put a wall-mounted handrail in place to meet code
compliance. Mount the handrail at 34 inches above the leading edge of the tread. It should be
198 inches in length and contain a wall rail bracket screwed into a stud or backing, every 4 feet.
In the case of an open rail section to one side of the stair, it is easiest to mount the balusters on an
angle cap.
You are now ready for inspection!
Stair building is an art. Do not expect to be able to learn it all in just one article. Many
experienced carpenters have difficulties building stairs. So if you've pulled your hair out a
little trying to achieve a quality stair project, you're in good company. Be patient and with a little practice, you'll be making your way up in the world on the steps you've just built.
STAIR-BUILDING TIPS
1. To create a softer edge where the carpet breaks over the tread edge, route the edge with a 1/2-
inch round overbite prior to installing the treads into the stringers.
2. If your material is spiltting, predrill your holes. This can also help prevent squeaking in the
future.
3. Glue blocks can be placed at the underside between the tread and riser intersection.
4. Another very important but sometimes overlooked item is to seal the underside of your stair.
This will prevent the stair from squeaking and warping.
Side Note 2:
STAIR-BUILDING TERMINOLOGY
Stair building is an art form with its own terminology. Here are some terms you may encounter when researching stair design:
Treads: Horizontal walking surface of the stair.
Riser: Vertical surface between two treads.
Carriage stringer: Support for the treads and risers; usually cut to have the treads sit on the horizontal plane and the risers nailed to a vertical cut.
Mop board/skirt board: Piece of lumber placed next to a carriage stringer and used to provide trim along a wall.
Wall rail: The grab bar along the pitch of the stair; usually mounted 34 inches off the leading edge of the tread. A wall rail should be 1 1/4 to 1 1/2 inch in diameter for ease of grip.
Handrail bracket: Metal piece of hardware that is used to mount the wall rail to the wall.
Handrail: Shaped wood member used in conjunction with posts and balusters to provide a safety barrier on an open balcony or open pitch section of the stair. This railing can also be wall mounted.
Post (newel): Vertical wood or support member at the landing or start of a stair. A post can be square or turned. A standard post diameter is 3½ inches.
Wall cap: Board used to decorate a half wall or used to mount balusters onto.
Balusters: Upright support of a handrail that prevents objects or people from going over the edge of a balcony or open side of a stair. Balusters are also referred to as spindles, pickets or turnings.
Headroom: Space from the leading edge of a tread to the header directly above. Six feet, 8 inches is a minimum guideline to follow.
Total rise: The dimension from one finished floor to the finished floor above.
Nosing: The overhanging lip of the tread. Standard nosing is 1 1/4 inches.
Tread depth: The cut dimension of the stringer; depth of the horizontal walking surface less the nosing dimension. Standard tread dept is 10 inches.
Riser height: The vertical dimension between two treads; this dimension must be equal throughout the total flight. Standard rise height is 7 5/8 inches and should not exceed 7 3/4 inches.
Total run: The length of all of the treads combined.
requirements are summarized by these sketches courtesy Carson Dunlop.
The minimum recommended stair width is between 34" and 36" ACROSS.
The minimum recommended stair landing length is 36" (or a length and width sufficiently
greater than the swing of the door if a wider door is present.
Is a landing required at the top of stairs?
Note: a stair top landing is not required if the door at the top of the stair opens away from the
stairwell.
In these sketches required handrails have been omitted for clarity.
Stairway Height, Width, Headroom Requirements
Stairway headroom or "overhead clearance": the distance from the top of the stair tread to the ceiling above, measured at the stair tread nose, should be six feet eight inches (or more). (Stairway headroom should be => 6'8" over tread or landing)
Stairway maximum height: the total vertical rise of a straight run of stairs should be twelve feet or less between floors. For higher total rises a landing may be required.
(Stairway maximum height should be <= 12' between floors - this means landings could be required)
Also see Stairway headroom and see Stairway landings
Exceptions to stair dimension requirements may be made for stairs giving access to non-living
areas of a building such as storage lofts and mechanical rooms. Check with your local building
officials.
Step Riser Height Specifications & Common Stair
Construction Mistakes
Stair Step Risers
Step riser specifications riser height (<= 7.75") Step riser height uniformity (<= 3/8" variation) Step riser slope (out of vertical) (<= 30 deg measured from horizontal surface of the tread) Step risers: open risers are permitted provided the opening will not pass a 4" sphere (child
safety)
Stair Riser Defects
Stair risers of uneven height - no variation greater than 0.375 inches is allowed Stair risers of improper height, too tall Stair risers of improper height, too short
Bad Deck Stair Example: Nothing is right about the exterior stairs shown in our photo from a
1991 home inspection:
This stair stringer is too-deeply notched and could split; The stair risers are too high, as our client is showing with our tape. The stair treads do not have enough depth - the treads were made from a single 2x6 (so they are
5 1/2" in depth). There is no railing on the steps although the height above ground is more than 30". The deck and platform railing is open with no guardrail balusters.
Closed stair treads using a solid riser are shown at the left of the sketch and
Open stair treads are shown at the right sketch. "Open stair treads" means that no solid riser is
installed between the stair treads.
Stair tread nose projection and radius: stair treads should have a projecting nose that is
rounded and projecting a maximum of 1.5 " over the tread below.
The requirements for a projecting stair nose over the tread below may be amended for open riser
stairs in some jurisdictions, but in no case should the front of a stair tread be more than 1.5" back
from the inside edge of the tread below - see sketch annotations. [Click any of our images to see an
enlarged, detailed version]
Stair tread thickness: The minimum tread thickness for stair treads supported by risers is 1".
Notice that the minimum stair tread thickness is increased to 1.5" when the stair tread is not
Ok so you need a new staircase but don't know where to start, the first area to focus on is the layout of the staircase and the size the staircase will take up and the size of the stairwell required, the information below and the staircase layout plans we have online will help you with this. Once you know the type of staircase you need the next step is to decide on the style and materials you would like the staircase making in, you will find ideas across the whole web site and an idea to costs in this section.
Staircase Layout
The first thing you need is the layout of the staircase, this is governed by your sizes and the rules set out in Building Regulations document K.
Are you going to design the stair layout yourself ? Do you have drawings prepared by your Architect? Is the staircase a Replacement Staircase?
Designing the Staircase Layout The first thing to do when sorting out a new staircase is to measure the total rise, this is the measurement from finished floor to finished floor level. ( Floor to Floor)
Once you have established the rise the next step is to establish the number of risers required for this particular staircase,
for a domestic staircase the individual step rise must be no more than 220mm to stay within building regulations (Part K). The height of a riser on a standard staircase is 200mm so idealy you should be looking to get as close to this as possible.(Eg :- 2600mm Total Rise (floor to floor) divided by 13 would equal 200mm, equaling 13Nº risers.) Or just let Stairplan know the floor to floor measurement on your enquiry.
Now you have the number of risers required you now also know the number of treads required, you require 1Nº less tread than the number of risers. (Eg :- 13Nº risers 12Nº treads.)(The top tread is only a nosing that attaches to the Trimmer Joist at the top of the staircase.)
The next thing you have to do is work out the tread size required otherwise known as the going, the going is the measurement from the face of one riser to the face of the next riser. The minimum going for a domestic staircase to comply with building regulations is 220mm and the pitch of a domestic staircase must not exceed 42º. Use the chart on the Rise and Go page to help you identify the correct Going size to suit your riser height. (Eg:- for a riser height of 200mm a going of 223mm should be chosen.) Width - there is no restriction with how narrow you can go with a staircase but the width of a standard flight of stairs is 860mm, For a main staircase I would suggest trying to maintain a width between 800mm and 900mm and I would not recommend a width of less than 600mm for a loft conversion. Will a Straight flight fit? Well you have the going size of each tread now and the number of treads required so you will have a total going length for the staircase, on top of this total going length you will need to add on the thickness of the top riser and the depth of the Nosing used in the construction of the staircase.(Our standard nosing overlap size is 20mm, the standard riser thickness is 9mm making the add on 29mm, we suggest you use 30mm). The room you need at the top and the bottom need to be at least the width of the staircase, if you have a door opening in to the space at the bottom of the staircase you need to be 400mm away from the door when it is open, at the top you don't want any doors opening into this space at the top of the staircase, for more information on this look at the relevant pages in the Building Regulations.
A Straight Flight Wont Fit? Corners - When it comes to corners you have a number of options the simplest option is a 90º quarter turn landing for this you only need to allow the width of the staircase, the next option is a 3Nº tread kite winder for this you need to allow approximately 900 x 900mm for a standard width staircase (860mm) in the corner, depending on your going and the width of your staircase the size of a 3Nº tread winder changes, a good guide for the minimum size is 750 x 750mm for a 600mm wide staircase, the next option is a 4º tread winder for this you need to allow approximately 960 x 960mm on a standard 860mm wide staircase, again depending on your going and the width of the staircase this size will change. When you send in your enquiry on a winder staircase you can leave this technical detail down to us this is just a guide for you to understand the space you need.
Headroom You need a minimum of 2000mm of clear headroom above the pitch line on a domestic staircase to comply with building regulations (there is a slight relaxation on this for loft conversions look at the appropriate page in the building regulations).A typical size for your Stairwell is to have it the same size as the staircase layout, usually you wouldn't get away with a staircase being more than half a tread under the stairwell on a typical standard rise height staircase. Take care when your planning on where to put your staircase especially when your going into your loft and make sure you stair well opening is big enough. Don't always rely on your architects drawings sort your stairs out while it is still possible to alter your stairwell as it could get expensive to alter it later. If your staircase is going to go over your exiting set of stairs think about the headroom on the flight below also. If you are trying to plan a staircase to go up into your loft a good place to start is in the loft this is because you are usually limited to where you can exit the staircase in the loft space due to the head room in the loft space.
North America tens of people die and tens of thousand people get injured every year from
the falls on stairs. The American National Council on Compensation Insurance estimated in
2001-2002 that the cost of such fall injuries was second only to those caused by motor vehicles.
The vast majority of stairway falls result from a loss of balance, just as falls are on the level. Please see our OSH Answers document on Prevention of Slips, Trips and Falls.
A very common contributing factor is neglecting to use handrails. The consequences can be quite nasty.
Because stairway accidents can cause severe injury and even death, building codes for
stairs and ramps are justifiably very rigorous. Good design can substantially reduce the
potential for mis-stepping by providing us with the means to retrieve our balance, but even
the best design cannot eliminate falling hazards entirely. The need for proper design also
applies to ramps. The fact is that some incidents can be caused by inattention and unsafe
behaviour.
The best approach to minimize the hazard of falling down stairs is to encourage the building
of well-designed stairways, combined with training focused on raising our awareness of the potential for disaster.
What factors must we consider in designing safer stairs?
Stair dimensions
Figure 1 shows the recommended dimension ranges for all the important elements of stairways.
D* - Step width: 90 cm min. E* - Tread depth: 23.0-35.5 cm
Within a staircase, treads shall have a uniform run and tread depth that does not vary more than 0.6 cm*.
* Values are from the National Building Code of Canada (2005). Always check with your local jurisdiction as requirements are different in each area.
The maximum range for a stair slope is 20º-50º. However, because the majority of people
prefer a slope of 30º-35º, this is the recommended range.
Steeper stairs change the way you climb them because the steeper they are the more effort
you exert. The ratio of riser height and tread depth has to be adjusted accordingly. (See Figures 2 and 3)
Figure 2
Figure 3
From: Kodak's ergonomic design for people at work. 2nd ed. John Wiley & Sons, 2004. p.244
The dimension of risers or treads in a stairway should not vary more than 1 cm. When doors
open directly into the stairwell, a 50 cm-wide platform should be provided beyond the swing
of the door. The recommended maximum number of steps between landings is 18, with no
more than two flights without a change of direction. The depth of any landing should be at least equal to the width of the stairs.
Stair surface
To reduce the risk of slipping on stairs, non-slippery surface on the whole steps or at least
on the leading edges is crucial. Such a surface can be made of rubber, or metal or painted
with special slip-resistant paint. Regular maintenance of the stairs in good repair plus good
housekeeping can reduce hazards for tripping.
Stair handrails
Attempts to design aesthetically pleasing stairways including handrails must not
compromise functionality.
The prime function of the handrail is for holding as support while going up or down stairs.
It is therefore crucial to be able to grasp it quickly, easily and firmly if you should start losing your balance.
Figure 4 shows the recommended cross-section and dimensions of a good handrail. Ideally
the cross-section should be round (diameter 4-5 cm, with circumference of 12-14 cm) to allow for a good firm grip.
Figure 4
You should be able to run your hand smoothly along the entire length without having to
adjust your grip. You should apply the so-called "tennis-racket grip" at all times when possible.
Guardrails of at least 40 cm above the surface of the stairs are needed to prevent falls off the side of the stairs that are not equipped with a banister.
Visibility on stairs
Improving visibility on stairs significantly reduces the risk for common mishaps caused by
misjudging distances. Otherwise you can trip on a step or miss it completely. You can catch
a heel on the edge of a step. Such mishaps are a routine cause of twisted ankles, sprained knees or more serious injuries incurred by a total fall.
Recommended illumination should be at the minimum 50 lux level.
Use angular lighting and colour contrast to improve depth perception.
Use matte finishes on the treads to avoid glare.
Avoid patterned carpeting that may visually hide differences in depth. Be very cautious on stairs if you are wearing bifocal glasses.
Work activity
Use any means to persuade people to grasp the handrail while both ascending or
descending stairs.
Avoid carrying objects with both hands.
Do not carry bulky objects that block your vision.
Housekeeping
Good housekeeping is also vital to stair safety:
Nothing should be sticking out the surfaces of stairs, handrails or bannisters (like
nails or splinters) that could cause a fall.
Spills, wet spots, or any debris should be immediately cleaned up.
Broken or malfunctioning lighting should be repaired or replaced.