You're currently in Studco Australia Studco Australia

Change Location

Studco UK Studco UK Studco US Studco US

You're currently in Studco Australia

Studco Australia

Change Location

Studco UK site switcher image

Studco UK

Studco US site switcher image

Studco US

Visit Our Brands

EZ Concept Australia site switcher image

EZ Concept Australia

Resilmount Australia site switcher image

Resilmount Australia

EXTERNAL SOFFIT CEILINGS THE CORRECT INSTALLATION METHOD

How to correctly install external soffit ceilings.

An external soffit ceiling is any ceiling built outdoors or subject to external wind pressures, such as a verandah on a multi-storey apartment, a covered walkway or a wet-weather shelter at a sports pavilion.

We regularly hear reports of incorrect installations of external soffit ceilings, where practices deemed as acceptable for internal ceilings have been used to install ceilings that are clearly external.

Ceilings installed in these circumstances will experience considerable uplift or upward wind pressure, much greater than that experienced indoors, and if the standard adjustable spring hanger brackets are used (Studco M520 or M534), there is a risk that the ceiling system will move up and down on the hanging rod, causing the system to be weakened and damaged.

A basic rule of thumb for external soffit ceilings is that no adjustable mechanisms can be used: all parts of the ceiling system must be securely fastened by means of screws or bolt/nut combination.

To achieve this, the system must be suspended from the substrate with a downstrut, such as a length of steel stud or top cross rail (see Figure 1). This eliminates any possible upward or downward movement of the ceiling system. Alternatively, you can use a threaded rod which is locked off with two nuts and the Studco M24 bracket. For fixing spacings, refer to the table (below right).

The maximum uplift pressure suitable for each installation must be determined by the project engineer and all ensure that the engineer agrees with your interpretation of this table prior to installation. Some installations may require a variation to these spacings, depending on the building type, location and other limiting influences.

 

FIXING SPACINGS FOR EXTERNAL SOFFIT CEILINGS

SPACINGS

UPLIFT PRESSURE

STUDCO M28 TOP CROSS RAIL (mm)

DOWN STRUT (mm)

PULT (MAX) kPa

 1200

1200   0.98
900  1200  1.31 
900  900  2.33 
900  600  5.24 
600  600  7.86 

 

FOOTNOTES

  1. Servicability limit state deflection rateio L/250.
  2. If TCR spacings = 1200mm, Studco M29 furring channel to be installed at 600mm centres. If TCR spacings = 900mm or less, Studco M29 furring channel to be installed at 450mm centres.
  3. Fastener connections to be in accordance with fastener manufacturers specifications
Soffit Tech Tip

For architectural specifications or installation advice, please contact Studco Building Systems for fast, friendly service at techadvice@studcosystems.com.au  or call 1800 STUDCO