2. 20
Chapter
Stair Construction

3. Objectives Identify the various types of stairs.
Define basic stair parts and terms.
Calculate the rise-run ratio, number and size of risers, and stairwell length.
Lay out stringers for a given stair rise and run.
Prepare sketches of the types of stringers.
List prefabricated stair parts that are commonly available.

4. Stairs
Series of steps at elevated measured distances leading from one level of structure to another
Construction requires high degree of skill
Carriages are inclined supports that carry treads and risers
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5. Types of Stairs Two stair categories Stairs may be Service Main Closed
Open
Combination of closed and open

6. Platform Stairs Include landings where direction is usually changed
L-type
Double L-type
U-type
Often used in split-level houses

7. Straight Run Stairs
Continuous from one floor level to another without landings or turns
Require long stairwell in floor above to provide headroom

8. Winding Stairs Have circular or elliptical shape
Gradually change directions as they ascend from one level to another
Often require curved wall surfaces that are difficult to build
Usually found only in high-end homes

9. Stair Parts
Stairs are basically sets of risers and treads supported by stringers
Total risers is always one greater than total number of treads
Ideal riser height is 7″
Ideal tread width is 11″

10. Stairwell Framing Timing for stair constructions varies
Rough openings must be carefully laid out and constructed
Trimmers and headers in rough framing should be doubled
Providing adequate headroom is important

11. Stair Design
Mathematical relationship between riser and tread is important
All treads in stair run must be same size
Same is true of risers

12. Widths and Handrails Stairs should be wide enough to allow
Two people to pass without contact
Furniture to be moved
Handrails are used on open stairways constructed with low partitions or banisters
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13. Stair Calculations To calculate number and size of risers and treads
Divide total rise by 7 to find number of risers
Round to whole number of risers
Divide total rise by that number to determine unit rise
Number of treads is one less than risers

14. Stairwell Length
Stairwell opening size must be known during rough framing operations
Amount of headroom required must also be known
Add thickness of floor structure
Divide total vertical distance by riser height

15. Stringer Layout First determine riser height
Use framing square to lay out stringer
Trim bottom end of stringer to adjust riser height for tread thickness

16. Pro Tip Be very accurate in laying out stringers
Use sharp pencil or knife
Make lines meet on edge of stock
Use stair gauges or clamp strip of wood to blade and tongue

17. Treads and Risers
Thickness of main stair tread is generally 1 1/6″ or 1 1/8″
Vertical and sloping stair riser shapes are used
Nosing is part of tread that overhangs riser
Basement stairs may be constructed with open risers

18. Types of Stringers
Treads and risers are supported by stringers solidly fixed to wall
Built-up stringers
Cut-out stringers
Housed stringers
Stairs are often built as fully-assembled units and taken to jobsite
Top Tread Stairways

19. Winder Stairs May be useful where space is limited
Require full-size or carefully scaled layout plans
Check local building codes to see if winder stairs are allowed

20. Open Stairs Require decorative enclosure and support for handrail
Principal members of balustrade
Newels
Balusters
Rails
Balusters are joined to stair treads or shoe rail

21. Stock Stair Parts Available in wide range of stock sizes
Ordered through lumber and millwork dealers
Stringers are made in two sections for easier shipping

22. Spiral Stairways Eliminate framing and save space
Available in aluminum or steel and in variety of designs
Use of spiral stairs is often restricted by building codes

23. Spiral Stairways Drawing

24. Disappearing Stair Units
Can be purchased ready to install
Operate through opening in ceiling
Swing up into attic space when not in use
Ceiling opening should be framed as ceiling joists are installed
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