Slotted Deflection Track: Application and Installation

A slotted deflection track or Slip track is a part of many steel framing system (SFS) wall assemblies where there is movement between the primary (Structural concrete or steel) and secondary structures (Light gauge steel framing). Building movements are initiated by any external forces like wind, seismic activity, and snow load.

In a region subject to heavy snowfall, a deflection track may be specified by code to counter the changes in roof loading that occur as the seasons change. Slotted deflection tracks come in different specifications to cope with a range of performance requirements.

On external walls, where cold-formed steel (CFS) studs are used slab-to-slab, slotted deflection track will allow the floor or roof above it to deflect so as not to transfer axial loads to the wall studs.

Here’s our guide to slotted deflection track, where it is most used, and how to install it as part of a wall assembly.

Slotted deflection track in use in a steel-frame structure.

Deflecting Loads in Construction and when you want to consider adding deflection track

In structural engineering deflection is the amount by which a structure will change shape when a load is applied to it. Deflection track helps walls adjust to compression and tensional forces.

An example of deflection occurring on a member after a force (F) is applied which changes its shape. The (f) is the amount of deflection.

The load on a building could be wind pressure, heavy snow loads, seismic events in the form of a single event or sustained pressure from everyday conditions. Loading can come from the construction of the building itself. Point loadings from roof trusses, or uniformly distributed loads can cause deflection. Shear loadings, ground pressure, and other loadings all apply pressure to deflect. Deflection can also be caused by the movement of people walking on the floors above a stud wall. Whether a building is for residential occupation, or a public building such as a school, office, or hospital, the end use will inform the designer of the potential live loadings that human beings impose. Here are the common deflection loads structural engineers must account for:

Dead loads: These are the constant loads a building carries due to its own weight. This includes the weight of structural elements like beams, columns, floors, walls, and the roof.

Live loads: These are the variable loads imposed on the building by occupants, furniture, equipment, and stored materials. Live loads can change depending on the building’s function and use.

Snow loads: In regions with snowfall, the weight of accumulated snow on the roof can cause deflection. Building codes consider the expected snow load for a specific location in design.

Wind loads: Wind blowing against the building creates lateral forces that can cause swaying and deflection. The building’s shape and height play a big role in how it handles wind loads.

Seismic loads: Earthquakes create ground motion that shakes the building, causing deflection. Seismic zones have stricter building codes to ensure structures can withstand these forces with minimal deflection.

Other loads: Depending on the building’s use, there could be additional deflection loads. This could include water pressure in a swimming pool, impact loads in a sports facility, or vibration from machinery.

What is Slotted Deflection Track?

Slotted Deflection Track, also called Slip Track is used for the top of a wall assembly to allow vertical movement up to 1 ½ inches. It is designed to provide a connection to the roof or floor above while allowing for shear extension and compression forces. It resembles a regular metal stud track with deep grooves in it to allow for studs to screw into it. The naming of Slip track/Slotted track is similar to the regular metal stud track but instead of a S or a T the center letters are SLT. A 6″ 18 gauge slotted track would expressed as 600SLT250-43 or simply just 6″ deflection track.

What does deflection track help with?

As buildings naturally bend slightly under various loads. Without deflection tracks, this movement could directly transfer to the walls, causing cracks in drywall, paint, or even structural damage to the wall framing itself. The deflection track acts like a buffer, allowing the upper part of the wall to move independently, protecting the rest of the wall from stress and potential damage.

Non-Structural Deflection Track Use: Internal Partition Walling

A deflection track is used for framing of interior non-structural partitions. It is necessary when an interior partition needs to tie into the superstructure for stability which makes it subject to the larger structure’s deflection. The typical gauges are used in this non-structural application are 30 mils and 27 mils. We manufacture them in 6″ and 3 5/8″ applications with codes like 600SLT250-30 and 362SLT250-27.

The wall in this case is attached to the metal bar joists from the ceiling. If there is a snow-load or heavy rain event this could result in the wall sagging from compression and the drywall attached to these studs would form cracks.

There is often a detail on the structural drawings that specifies the maximum expected movement. The gypsum wallboard and other wall finishes will have to be installed to the specified gap measurement to allow for extension or compression movement. Typically, any gap will be filled with a compressible fire barrier and the top of the wall hidden above ceiling framing.

To prevent rotation of wall studs it is good practice to install them with a uniform gap, fixed with wafer-head screws to both flanges in the center of the vertical slots. This allows for vertical movement without imposing axial loads that might distort the wall frame.

Slotted track gives you the deflection management required in all settings.

Deflection Track in Structural Steel Applications: Curtain Walling

Exterior walls subject to wind shear loads are called curtain walls. Low-rise commercial buildings such as distribution centers, retail outlets, and storage facilities frequently have light gauge steel curtain walls. Deflection track is used when the light gauge steel walls tie into structural steel or concrete wall/floor systems. A steel-framed design is less rigid than a reinforced concrete building, but both benefit from the use of a slotted deflection track.

In steel framing deflection track system is the easiest way to manage dynamic loads along the length of a curtain wall. With studs left free-floating within the head track.

Slotted deflection track is being specified over regular leg track more and more frequently as the ability to fix studs to the track and still allow for vertical movement is seen as very positive when considering a building as an integrated system.

A building is a system where each element works together.

Below is an engineering detail on how to install structural track into red-iron. In this case the engineer has the installer leave a gab of 3/4″. The screws used here are #12 self tapping screws.

Deflection Track in Concrete Primary Frame Construction

Reinforced concrete is commonly used for high-rise residential, office, and multi-use buildings. Where steel framing is used to clad the external face of the building, managing deflection can be complex.

Allowable designed deflection in reinforced concrete structures is more stringent than in steel-framed buildings. As a result, the requirement for slotted track in internal partition walling will likely be minimized and only used when framing slab-to-slab or slab-to-roof.

It may still be required in strategic areas, and as such, it will be detailed in the structural engineering specifications.

Typical track detail in concrete and metal decking construction.

How is a Slotted Deflection Track Installed?

A slotted deflection track is installed much the same as an unslotted head track would be. Fixed directly to the overhead slab, or roofing members, the slotted deflection track should be fixed perfectly in line with the floor track.

The wall studs must have both flanges fixed to prevent rotation, with wafer-head screws. The screws must be installed at the center point of the slot to allow for equal vertical movement both up and down.

There is sometimes a requirement to firestop the top of the wall with a proprietary strip of mineral wool to prevent the spread of smoke during a fire event. During installation, the wallboard must be trimmed to allow for movement and the installation of any compressible fire-retardant material.

How much does slotted deflection track cost?

We here at US Frame Factory ship metal stud products world-wide. Here are is our current cost for slotted track.

NameProduct CodeCost/LF
3-5/8″ Slotted Track
EQ20 Gauge 3-5/8″ Drywall Slotted Track362SLT250-27$1.39
18 gauge 3-5/8″ Structural Slotted Track362SLT250-43$2.09
16 gauge 3-5/8″ Structural Slotted Track362SLT250-54$2.56
6″ Slotted Track
EQ20 Gauge 6″ Drywall Slotted Track600SLT250-27$1.75
18 gauge 6″ Structural Slotted Track600SLT250-43$2.65
16 gauge 6″ Structural Slotted Track600SLT250-54$3.25
8″ Slotted Track
EQ20 Gauge 8″ Drywall Slotted Track800SLT250-27$2.08
18 gauge 8″ Structural Slotted Track800SLT250-43$3.11
16 gauge 8″ Structural Slotted Track800SLT250-54$3.82
Large Size Slotted Track
18 gauge 10″ Structural Slotted Track1000SLT250-43$3.60
16 gauge 10″ Structural Slotted Track1000SLT250-54$4.41
18 gauge 12″ Structural Slotted Track1200SLT250-43$4.06
16 gauge 12″ Structural Slotted Track1200SLT250-54$4.98

Additional Recourses

Engineered Metal Trusses
Steel Framing Kits and Metal Framing Shipped Internationally
Structural Metal Studs

Leave a Reply

Your email address will not be published. Required fields are marked *