What Is a Stair Stringer and Its Types ?

What Is a Stair Stringer and Its Types ? . Staircase construction comes with a host of decisions that have to made. What type of staircase is being built? What are the best materials to use for the various components? What are the best styles use for the different staircase parts? In this article we will examine the best material for stair stringers and the different types of stair stringers.

When remodelling a staircase, it’s important to learn about and consider all possible features and their uses before deciding on an overall design. A stair stringer can often be a crucial feature in a staircase, but you may not know what it is or does.

What Is a Stair Stringer?

A stair stringer, which you might also see called a “string” or “stringer board”, is the housing on either side of a flight of stairs, either in an interior or used for an exterior location such as on a deck. The treads and risers that make up the steps of a staircase are fixed into stair stringers.

Generally speaking, a staircase will have two stair stringers. These will beon either side of the steps. If one side of a staircase sits flush against a property’s wall, the stringer that connects the treads and risers to the wall will be called the “wall stringer”, or the “inner stringer”. The stringer not against the wall will therefore be called the “outer” stringer.

What is a Stair Stringer Used For?

A stair stringer’s most basic function is to support the staircase or deck. Different types will then have a number of other functions, depending on the variety used.

Types of Stair Stringers

There are many different types of stair stringers available, in a range of material options. These can then be combined with different types of stair treads to create an almost endless series of combinations, both for commercial and residential properties.

The best type and material for stair stringers will depend on what you want for your staircase’s functionality and aesthetics. Here are the most common types for residential properties:

Read More : How to Calculate Land Area at Site?

Commercial and industrial stair stringer styles

Commercial and industrial stair stringers are usually made of steel, aluminum, or stainless steel. Common styles for these stair stringer materials include:

Double stringers (two stringers on outside of treads)
Center beam stringer (one stringer underneath the tread)

Double Stair Stringer

Double stair stringers include two stringers each at the outside of each stair tread. The double stair stringer is the most common stringer style for commercial and industrial stairs. The design is used for prefabricated stair systems and can work with many types of stair railings. Steel stairs designed with double stringers often use structural steel shapes:

Channel stringers
HSS tube stringers
Plates stringers

What Is a Stair Stringer and Its Types ?

Double stair stringer applications

Double stair stringers are commonly used for egress stairs in commercial buildings, for industrial stairs, and for residential metal stairs. The double stringer design provides added support to meet engineering requirements to ensure a safe and durable design.

Double stair stringer advantages and disadvantages

Pros

Great design for prefabricated stairs to make installation easier
Flexible and functional design for fire escape stairs and industrial stairs
Double stringer supports increase the strength of the stair to meet engineering requirements

Cons

Requires two stringers, which might increase cost

Center beam stringer

Center beam stringers are a type of mono stringer used in high-end feature stairs for offices, hotels, and other highly visible locations. This type of stringer uses a single beam, usually steel or stainless steel, that sits underneath the stair treads and provides the support for the stairs. Steel and stainless steel I-beams or HSS tube are common shapes used to fabricate center beam stringers.

Center beam stringer applications

Center beam stringers are a common type of stringer in monumental and feature staircases. The stringer is attached to the underside of the stair stringers and runs down the center of the flight.

Center beam stringer advantages & disadvantages

Pros

Provides a high-end design aesthetic for ornamental and feature staircases

Cons

Typically more expensive to construct and install

Residential Stair Stringer Types

Closed Stair Stringer

Also called “housed”, “routed”, “side”, and “box” stringers. These are positioned outside the treads and risers, so that the part of the staircase you walk on will be contained between the two.

Closed stair stringers feature notches, where the treads and risers can be inserted. The edge of the tread will not be visible and the vertical parts of the handrail (the balusters and newels) will typically be attached at the top of the stringer.

Pros

Closed stair stringers can be built with open or closed risers depending on the need and desired look.
Staircases with closed stair stringers are generally easier and less expensive to build. In many cases, pre-cut stringers are available.

Cons

Staircases with closed stair stringers tend to provide a more basic and functional look than staircases built with other styles of stair stringers.

Open Stair Stringer

Also called “cut” or “sawtooth” stringers. When you view a staircase using these stringers from the side, the treads will be exposed. The balustrade supporting the handrail in the construction will be set directly on top of the steps.

Open (cut or sawtooth) stair stringer applications

Open stair stringers are used in environments where the staircase needs to be visually appealing, including in residences and commercial buildings. They are not usually found in industrial settings.

Open (cut or sawtooth) stair stringer advantages & disadvantages

Pros

Staircases with open stringers usually provide a more sophisticated and appealing look than closed stair stringers.
Open stair stringers can also have open or closed risers depending on the function and style desired.

Cons

A staircase with open stair stringers is more difficult to build and is usually more expensive than a staircase with closed stringers.
Since the sides of the tread are exposed, they need to be treated to provide an appealing look.

Mono Stair Stringer

This is a single, heavy-duty stringer that is installed beneath the centre of the treads to support the staircase. These will normally be made of metal and are welded to each tread with a bracket.

All staircases with these stringers will have open risers. They are also a good-looking option for properties with ultra-modern staircases.

Mono stair stringer applications

Mono stair stringers are mostly used in modern homes and office buildings to achieve a contemporary look and are commonly used on spiral staircases.

Mono stair stringer advantages & disadvantages

Pros

Staircases with a mono stringer provide the most open-air look of any type of stair.
A variety of staircase styles, such as straight, U-shaped or winder, can be built using a mono stair stringer.
Mono stair stringers are extremely strong and durable and easily be designed around most building codes.

Cons

Mono stinger staircases need a customized, engineered stringer that is not readily available like pre-cut closed stair stingers.
Because both the treads and stringer are likely to be a custom design, this staircase design is typically more expensive.
Mono stringer stair cases are not normally used for long distances.

Twin Stair Stringer

This is a variety of the mono stringer type. Instead of one stringer in the middle of the staircase, two will usually be placed about 6 inches apart. They might also be placed off-centre for another aesthetically pleasing look.

Twin stair stringer applications

Like mono stair stringers, twin stair stringers are mostly used in contemporary residences and offices to achieve an open, modern look.

Twin stair stringer advantages & disadvantages

Pros

The stringers tend to be more hidden behind the stair treads than with a mono stringer design.

Cons

As with mono stringer stairs, twin stingers are not usually used for long distances because the stairs can twist.

Cantilevered Stair Stringer

A staircase that has a cantilevered stringer has one single side stringer. This stringer is mounted inside a wall and reinforced for strength. The treads are supported by this and protrude from the wall. The staircase will most often be open from the other side.

Cantilevered stair stringer applications

Cantilevered stair stringers are used in homes and offices to achieve a stunning architectural effect.

Cantilevered stringer — Cantilevered Stair Stringer

Cantilevered stair stringer advantages & disadvantages

Pros

With their floating appearance, cantilever stairs create a more open and spacious appearance to the room.
Floating stairs with cantilevered stair stringers provide one of the most modern, unique and visually interesting looks.
Because the stair stringer is installed in the wall, cantilever stairs can provide more headroom.

Cons

With cantilever staircases, the design of the support structure needs to be taken into consideration and installed into the wall before it is complete.
Due to the additional structural requirements, cantilever stairs can be more expensive to build than other types of staircases.
If not properly reinforced, the treads of cantilevered steps may sag on the open side.
Often, cantilever stairs do not have a railing to reinforce the floating effect, which can also make them more dangerous.

Residential Stair Stringer Materials

Steel Stair Stringer

Steel is highly praised as a material for stringers, owing to its strength and durability. It can also be used to create custom staircase options, such as curved and spiral staircases, and aids in achieving a modern look.

Steel stair stringer applications

Steel stair stringers are popularly used in staircases in homes, business and industrial areas. Steel stringers can also be used in outdoor applications, especially if made of galvanized or stainless steel. Prefab metal stairs with steel stringers are a good option if the staircase needs to be able to stand up to heavy weight use, such as in industrial applications. Bolt-together metal stairs use formed steel stringers for a functional, lightweight metal stair system. Structural steel stair stringers are used in the design and manufacture of commercial stairs.

Steel stair stringer advantages & disadvantages

Pros

The primary advantage of using a steel stair stinger is its strength and durability, which enables it to withstand high weight loads and high traffic.
Steel stringers can be shaped in almost any form, allowing you to create custom staircase options, such as curved and spiral, and also provide a modern look.
When metal stairs are desired, steel stair stringers are less expensive than those made of aluminum.
Steel stringers are easier to install than wood stringers as they can just be bolted together.
Because they are easier to install than wood stringers, prefab steel stringers are also less expensive to install
– whether you are completing a DIY project or hiring a professional.
Steel stair stringers require very little maintenance, whether indoor or out. They are resistant to extreme weather conditions, rot and pests.
Steel stringers are fire resistant providing an additional safety feature for egress stairs.

Cons

One of the biggest disadvantages of metal stair stringers is the noise caused when walking up and down the steps.
While less expensive than aluminum stair stringers, steel stringers are more costly than those made of wood.
If not done by and expert, the welding seams may look rough and even ruin the appearance of the stair stringer. If you are doing a DIY project, be sure to buy pre-fabricated stringers and make sure the welds are of high quality.

Aluminium Stair Stringer

Aluminium stringers can also help to achieve an ultramodern design while offering durability and strength, though at a lighter weight that is more easily installed than steel.

Aluminum stair stringer applications

Aluminum stair stringers can used in a variety of industrial, commercial and residential staircases.

Read More : pe civil reference manual

Aluminum stair stringer advantages & disadvantages

Pros

Due to its lighter weight, aluminum is less expensive to transport and install than steel, so it’s good to use when the stairs need to be portable
Installation of aluminum stair stringers is easy, which saves both time and labor costs.
Aluminum is very malleable and flexible and therefore can be constructed in a variety of shapes – including spiral stairs.
Due to its natural corrosion resistant layer, aluminum stair stringers are durable and require little maintenance.

Cons

Aluminum stair stringers are more expensive than those made of steel.
Because they are lighter weight, aluminum stair stringers are less sturdy than steel.
Aluminum stair stringers are more prone to nicks and scratches than steel stair stringers.
The oxide layer of aluminum tends to dull its metallic shine, giving the material a grayish appearance.

Wood Stair Stringer

Wood stair stringers come in different types of natural wood including oak, maple and walnut. Stair stringers can also be made from pressure treated or engineered wood. Wood stair stringers can be pre-cut for easier installation or uncut if a custom installation is preferred.

Wooden stair stringer applications

Wood stair stringers are normally found in residential or commercial buildings. In addition to their use as a support structure for the staircase, wood stair stringers add a warm and natural look to the room or environment.

Read More : civil engineering reference manual

Wooden stair stringer advantages & disadvantages

Pros

Wood stair stringers are durable and easy to clean.
Because of the variety of options available, wood is versatile and can compliment both classic and modern looks.
Pressure treated wood stair stringers are normally used for outdoor deck stairs. The pressure treatment prevents against rot and pests for years and tends to be economical.
Engineered wood is made from a thin layer of hardwood bonded over high quality ply-wood. Engineered wood provides stability, resists bowing and shrinking, and is more resistant to heat and water than solid hardwood. It is also generally less expensive and easier to install.

Cons

Unless very high-quality wood is used, you may have issues with it being straight and having an extreme number of knots.
Solid hardwood can be more expensive than other options, but generally increases the value of your home or building.
Unlike solid hardwood, engineered hardwood can be refinished only once or twice before the surface hardwood layer is exhausted.

FAQs

How many stringers are needed for stairs?

At least one stringer is needed for a stair designed with a center or mono stringer underneath the stair treads. Two stringers are used with a double or twin stringers positioned to the outside of the stair treads.

Do stair stringers need support?

Stair stringers may need additional support depending on the length of the stair stringer and the width of the staircase. Wood stair stringers typically need additional supports between 6′ and 10′ lengths while metal stair stringers typically do not require additional supports.

What is the maximum stair stringer length?

The maximum stair stringer length depends on the material used for stringer construction, the stringer size, and the stair building code requirements. IBC stair code limits stair stringers to a maximum vertical height of 12′ in a single run.

Can you build stairs without stringers?

You can build stairs without stringers if each stair tread provides it own structural support by constructing them as boxes or adding supports for each tread. Building stairs this way might be less economical than using stair stringers.

What Is a Stair Stringer and Its Types ?

What Is a Stair Stringer?

What is a Stair Stringer Used For?

Types of Stair Stringers

Commercial and industrial stair stringer styles

Double Stair Stringer

Double stair stringer applications

Double stair stringer advantages and disadvantages

Pros

Cons

Center beam stringer

Center beam stringer applications

Center beam stringer advantages & disadvantages

Pros

Cons

Residential Stair Stringer Types

Closed Stair Stringer

Pros

Cons

Open Stair Stringer

Open (cut or sawtooth) stair stringer applications

Open (cut or sawtooth) stair stringer advantages & disadvantages

Pros

Cons

Mono Stair Stringer

Mono stair stringer applications

Mono stair stringer advantages & disadvantages

Pros

Cons

Twin Stair Stringer

Twin stair stringer applications

Twin stair stringer advantages & disadvantages

Pros

Cons

Cantilevered Stair Stringer

Cantilevered stair stringer applications

Cantilevered stair stringer advantages & disadvantages

Pros

Cons

Residential Stair Stringer Materials

Steel Stair Stringer

Steel stair stringer applications

Steel stair stringer advantages & disadvantages

Pros

Cons

Aluminium Stair Stringer

Aluminum stair stringer applications

Aluminum stair stringer advantages & disadvantages

Pros

Cons

Wood Stair Stringer

Wooden stair stringer applications

Wooden stair stringer advantages & disadvantages

Pros

Cons

FAQs

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