What is Stringer Beam? |Stringer Beam Staircase Details | Different Types of Staircase Stringers
What is Stringer Beam?| Stringer Beam Staircase Details | Steel Stair Stringers |Wood Stair Stringers |Alluminium Stair Stringers |How Much do Stairs Stringers Cost? |Stair Stringer Spacing
What is Stringer Beam?
Stringer beams are structural components that support a floor or deck along their longitudinal axis. They are generally inclined secondary beams that sprout from primary beams or supports and are used to convert distributed loadings from a slab into point loads.
They are also particularly beneficial in staircases where the thickness of the waste would be very considerable relative to the span of the flight due to deflection requirements and material economy.
When used in stairs, stringer beams can be built with two edge beams (simply supported) or with a central beam (double cantilever).
Stringer Beam Staircase Details
Staircases are structural components that allow movement from one floor to another in a structure, with landings at appropriate intervals to provide users with comfort and safety.
Staircases are made up of an inclined slab called as the Waste and a sequence of connecting steps that connect one floor to the next.
The steps are made up of a horizontal distance called the Tread and a vertical distance called the Riser.
Staircases are one-way slabs, although the dead load portion of the waste is typically augmented by a slope factor to account for the inclined slab.
A stair stinger is a structural element that is put on either side or in the center of a flight of stairs and is fixed to the threads and risers.
The stringer’s major function is to give a framework or support for the tread and risers, as well as to conceal the edge of the stairs, exposing the tread profile.
A beam-slab combination is cost-effective, and a beam without a slab is provided with hanging steps, i.e., cantilever on either side of the beam.
Beam-and-slab staircase construction is common in concrete, cast-in-place concrete, precast concrete or steel structures. However, there are many different examples of over two hundred different concrete and steel staircase types that can be fabricated from a single design.
The most common type of stair is the tiered-in-place stair. These are installed in the field using traditional methods such as hoisting, or by using a traveling crane with special equipment.
The wire rope and hydraulic jacks used for lifting the stairs can have a direct impact upon the structural integrity of the building.
A special engineered tiered-in-place stair system can be used to minimize the potential instability and structural damage from such hoisting.
Tiered-in-place stairs can also be installed in a crane lift, but these are often very expensive to install, making such systems impractical for many buildings.
Building codes require that the size of the opening for a tiered-in-place stair system must be at least twice as large as the range of the largest stair that will likely be installed in the building.
Stair Stringer Spacing
Deck staircases are normally constructed of 2 x 12 stringers spaced 12 to 16 inches apart. They are supported by a sturdy foundation and are hung from the deck with hangers. They include risers (also known as toe kicks), treads, and railings. The stairwell must be at least 36 inches wide.
The number of stringers required is determined by the width of the staircase and the material of the treads.
Cut stringers can be spaced no more than 18 inches apart, thus a 3-foot-wide staircase has three stringers, and a little broader set of stairs (say 3 feet 6 inches) requires four stringers. The maximum 18-inch spacing assumes 5/4-inch wood decking or 2-by stock treads.
Consult the decking manufacturer’s specifications when using synthetic decking for treads; many require stringers to be spaced no more than 12 inches or 10 inches apart, and some even require spacing as close as 8 inches. Pay close attention to the installation instructions provided by the manufacturer.
Different Types of Staircase Stringers
1. Double Stringer
Double stair stringers have two stringers on either side of each stair tread. The double stair stringer is the most commonly used stringer style for commercial and industrial stairs.
The design is suitable for prefabricated stair systems and can be utilized with a variety of stair railings.
2. Cantilevered Stringer
A cantilevered stringer staircase has a single side stringer that is installed inside a wall and strengthened.
The stinger-supported treads protrude from the wall, and the staircase is generally open on the other side.
3. Mono Stringers
Mono stringers have one stringer cast into a stair tread. Mono stringers are used primarily in residential and light commercial application.
4. Multiple Stringers
Multiple stringers use multiple stringer beams that are bolted or screwed to the riser and tread joints.
This allows the step landing to extend longer along the stair, which provides additional support for structural components within a building such as HVAC ducts, plumbing piping and elevator shafts.
5. Open (Cut or Sawtooth) Stringer
An open stringer is a stringer without any riser and tread. It is used for building commercial or industrial stairs when wide landings are not needed.
6. Floating Stringers
The floating stringer is a very special type of beam-slab system. It uses beams that float on a slab so that the stiles and riser are off the ground.
7. Pre-Engineered Stair Stringers
A pre-engineered stair stringer is one with a size and shape that has been pre-fabricated to fit each step and landing.
8. Routed Stair Stringer or Housed Stair Stringer
The routed stair stringer incorporates an internal horizontal or vertical open plenum to accommodate openings in the stair stringers.
It consists of notches includes treads, risers, and wedges can be inserted also known as box stringers.
The notches are combined with the stringer to support the stairs treads.
Material for Stair Stringers
The ideal material for a stair stringer is determined by the functionality of the staircase as well as the intended appearance. Stair stringers are commonly made of steel, aluminum, and various types of wood.
1. Steel Stair Stringers
Steel is a commonly used material for stair stringers because of its durability and relatively low cost. Steel stringers are usually made from steel plate or other similar metal form.
The main disadvantage of steel stair stringers is that they rust easily when exposed to water and atmospheric weathering, leading to significant deterioration of the material.
Steel stair stringer companies will typically offer pre-treated or pre-painted products, which will minimize the development of rust on the metallic components.
2. Aluminum Stair Stringers
Aluminum is a popular choice for stair stringers because of its light weight, excellent corrosion resistance, and ease of fabrication.
Aluminum is also more durable than steel, making it more acceptable to building codes and code administration entities. Alumimum stairs are fabricated from extruded aluminum or extruded aluminum tubing.
Extruded aluminum can be used to make treads, risers, and tie rods in stair stringers to the same dimension as the steel counterparts.
The light weight of aluminum is its main advantage over steel, which can reduce the overall weight of the stairs and improve its durability.
An additional strength benefit of aluminum is that it has a higher yield strength than steel, making it more resistant to stress-induced failure.
3. Wood Stair Stringers
Wood stair stringers are a popular choice for commercial or residential stairs because of their relatively low cost and ease of fabrication.
Wood stair stringers are also used in the construction of exterior decks, making them a cost-effective option for building staircases.
Like wood decking, wood stringers require careful and consistent installation to avoid warping or splitting.
The quality of the wood will have a direct impact on how it holds up to weather conditions and overall wear and tear over time.
Stringer Beams FAQs
Q. What is a stringer beam?
A. Stringer beams are structural components that support a floor or deck along their longitudinal axis.
Q. What is the most common use of a stringer beam?
A. The stringer beam plays an important role in the structural integrity of the stair system, but they are often not used to their full potential.
Many people are unaware that stringer beams can be used to provide additional support to other structural components within a structure.
They can also be used to support decorative, aesthetic features such as railing and balustrades.
Q. How are stringer beams different from other stairs?
A. Stringer beams are typically made from steel, aluminum, or wood. These structural components have a purpose in the construction of staircases that differs from their function on other structures.
While many stringers are used to carry loads within the stairway, stringer beams can be used for aesthetic and decorative purposes as well as providing structural support.
Q. Do I need to be licensed to install stringers?
A. Yes. Anyone who uses stringers for the purpose of installing a stair system must be licensed as a contractor in order to obtain the proper permits.
Q. How do I select stringers for my job?
A. The type of stringer that you choose will have a direct impact on how the stair system looks and functions within your project space.
The properties of a stringer are determined by its size and the materials from which it is made.
For example, you may want to use stringers that are smaller in size to provide additional structural support where there is an aesthetic need.
Q. What are some common uses of stringers?
A. Stringer beams can be used for a variety of purposes, such as supporting stringer treads, carrying loads on curved stairways, and supporting decorative features such as railings or balustrades.
Q. How do I know what type of stringer I should use for my job?
A. Many of the features that you can determine on stringer beams include the type of material used to make the beams as well as their size and shape.
For example, when installing a stair system in a gymnasium, you may need to use small stringers that are long and narrow to allow for proper distance between treads.
Q. I am considering using stringers on my project. How do I decide on the types of materials that I will use?
A. The type of stringer that you choose will have a direct impact on the finished appearance and final functionality of your stairway.
For example, you may want to use stringers that are smaller in size to provide additional structural support where there is an aesthetic need.
Or, you may want to use longer and wider board style stringer beams to create a more ornate look for your staircase.
Q. Where would I find stringers in the building?
A. Stringer beams can be used for a variety of purposes, such as supporting stringer treads, carrying loads on curved stairways, and supporting decorative features such as railings or balustrades.
Q. How much do stringers cost?
A. The cost of the stringer that you choose will depend on its size and the material it is made from.
Many of the materials used to make stringers are available for about the same price or sometimes cheaper than steel. The cost of wooden stringer beams is often less expensive than the cost of steel beams.
Stringers will cost between $4 and $8 per step, per stringer, with a minimum of three stringers required depending on the width of the steps.
The cost of various railing styles varies greatly. Aluminum and glass will cost far more than a pine railing with pine balusters. Railings can cost anything from $25 to $70 or more in materials.
Q. What type of joints do I need to use with my stringer?
A. Stringer beams are typically assembled with a welded joint at each connection point, but there are other ways that you can attach your stringer to its foundation.
For example, you can use a bolted joint or a nailed joint. A bolted joint uses bolts to connect the stringers at each end, while a nailed joint requires you to install nails in the beams that are perpendicular to the stringer.
Q. I am considering using stringers on my project. What type of dowel connection should I use?
A. The type of dowel connection that you should use will depend on your system’s aesthetic requirements and overall structural strength.
For example, you may need to use a doweled system to hold the stringer in place during installation.
Or, you may want to use a regular structural connection between your stringers and its foundation.
Q. How much do I have to pay for my stringer?
A. The initial cost of stringers will vary depending on their size and the materials from which they are made.
However, the added cost for additional structural components such as beams and stairs will often be significantly higher than the costs necessary for concrete stairs or steel systems.
