20 Chapter Stair Construction 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. 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 pics721/Shutterstock.com Types of Stairs Two stair categories Stairs may be Service Main Closed
Open Combination of closed and open Platform Stairs Include landings where direction is usually changed
L-type Double L-type U-type Often used in split-level houses Straight Run Stairs Continuous from one floor level to another without landings or turns Require long stairwell in floor above to provide headroom 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 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 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 Stair Design Mathematical relationship between riser and tread is important All treads in stair run must be same size Same is true of risers 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 pics721/Shutterstock.com 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 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 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 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 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 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 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 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 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 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 Spiral Stairways Drawing 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 Rock Island Millwork