Timber Tie Downs for Wind Uplift Restraint
Roof framing needs more than accurate set-out when wind uplift becomes part of the structural design. Hobson Cyclone Strap Tie Downs are galvanised structural-steel straps designed to secure timber purlins, rafters & trusses to top plates & timber lintels, providing a purpose-made connection for timber framing exposed to uplift forces.
Manufactured from G300 structural steel with a Z275 galvanised finish, Hobson Cyclone Straps are available in 400 mm & 600 mm lengths. Both configurations use 25 mm wide x 1.2 mm thick punched strap & are designed to meet the minimum requirements of AS 1684 for their intended timber-construction applications.
Preparing the surrounding roof & wall framing connections? Explore Hobson | Bracings for structural wall bracing, Hobson | Joist Hanger for suitable joist connections or Structural Fasteners & Bolts for complementary structural fastening hardware.
► Designed to secure timber members against wind uplift
► Suitable for nominated purlin, rafter & truss connections
► 400 mm & 600 mm configurations
► G300 structural steel
► Z275 galvanised finish
► 25 mm strap width
► 1.2 mm material thickness
► Punched construction for specified connector-nail installation
► Designed to meet the minimum requirements of AS 1684
Correct tie-down hardware establishes a continuous connection where roof framing meets the supporting timber structure.
What Are Hobson Cyclone Strap Tie Downs?
Hobson Cyclone Strap Tie Downs are structural timber connectors, not transport straps. Their role is to connect suitable roof-framing members to the timber structure below so the nominated connection can resist wind uplift according to the applicable design.
Typical applications include securing purlins, rafters & trusses to top plates & timber lintels. The strap passes around or alongside the timber members according to the required installation arrangement then uses specified connector nails through its punched fixing positions.
Each verified Hobson Cyclone Strap is manufactured from G300 structural steel with a Z275 galvanised finish. The current family includes 400 mm & 600 mm options with a nominal strap width of 25 mm & thickness of 1.2 mm.
Wrapping the strap under the supporting member can also be used in specified installations to increase uplift resistance. That detail needs to be considered as part of the complete connection rather than decided after the strap has already been fixed.
For builders, carpenters & framing crews, the selection process starts with the structural tie-down detail: identify the members being connected, required strap configuration, length & specified nail arrangement.
Why Choose Hobson Cyclone Strap Tie Downs?
Wind doesn't need to move the whole roof to place significant demand on an individual framing connection. Uplift restraint therefore depends on correctly detailed connections between roof members & the supporting structure.
Hobson Cyclone Straps provide a defined timber-connection product for that purpose. Rather than improvising with general metal strap, installers can work from documented dimensions, material, finish, fixing requirements & installation configurations.
G300 structural steel provides the base material while the Z275 galvanised finish forms part of the product specification. Both should be considered when checking the strap against the construction documentation & environmental requirements.
Two available lengths also allow the product to suit different nominated connection arrangements. The 400 mm & 600 mm straps share the same 25 mm width & 1.2 mm thickness but shouldn't be treated as interchangeable where a particular length or wrap configuration is required.
For projects designed around AS 1684 requirements, using a documented tie-down product makes it easier to keep purchasing, installation & inspection aligned with the specified framing detail.
Common Applications
Roof Truss to Top Plate Tie Down
The junction between a roof truss & top plate is a critical point in the load path.
Hobson Cyclone Strap Tie Downs can be used in specified connections to secure trusses to timber top plates against wind uplift.
Strap length, positioning, wrapping arrangement & connector-nail installation need to correspond with the construction detail.
Before framing progresses beyond easy access, check that each required tie-down has been installed in the correct location.
Rafter to Top Plate Connections
Traditional rafter construction still requires a clear connection between the roof framing & supporting wall.
Cyclone straps can provide uplift restraint at suitable rafter-to-top-plate connections when specified for the structure.
Accurate placement matters because the strap needs to engage the nominated timber members rather than simply being fixed wherever space remains available.
For broader timber fastening requirements around roof construction, browse Screws & Anchors.
Purlin Tie Down
Purlins form another roof-framing connection where uplift restraint may be required.
Hobson identifies purlin securing as a specific application for its galvanised Cyclone Strap Tie Downs.
The appropriate installation depends on how the purlin relates to the supporting member & what the structural detail requires.
Check the connection before cutting, positioning or fixing surrounding materials that could restrict access.
Timber Lintel Connections
Openings in a timber frame change the arrangement of the members carrying loads around them.
Hobson Cyclone Straps can be used in nominated connections involving roof members & timber lintels.
Where a lintel connection appears on the structural or framing documentation, confirm the required strap arrangement rather than duplicating the detail used at a standard top plate.
For other connection hardware across timber assemblies, Bolts & Fasteners provides a broader pathway into mechanical fastening products.
High-Wind Timber Construction
Greater wind exposure places more attention on the continuity of structural connections throughout the building.
Cyclone Strap Tie Downs form one part of that connection system where they are nominated for timber framing.
Their presence alone doesn't make an entire structure suitable for a particular wind classification. The complete building design, connection schedule, framing system & installation requirements still determine the required solution.
Builders working in demanding wind conditions should follow the project documentation & applicable construction requirements rather than selecting tie-down hardware from a general description alone.
New Residential Framing
Installing tie downs during the normal framing sequence is considerably easier than returning after access has disappeared.
New residential construction allows straps to be positioned while trusses, rafters, purlins, top plates & lintels remain visible.
Organising the required 400 mm or 600 mm straps with their specified connector nails before roof framing begins can help crews complete connections as work progresses.
For accurate framing checks & member positioning, Measuring & Leveling Tools can support routine site set-out.
Product Selection Guide
Identify the Connection First
Start with the members that need to be tied together.
A truss-to-top-plate connection may not use the same arrangement as a purlin or lintel detail.
Check the plans, framing documentation & applicable requirements to establish where the Cyclone Strap belongs & how it needs to engage the timber.
Product selection becomes much clearer once the actual connection has been identified.
Choose 400 mm or 600 mm
Length affects how much strap is available to form the specified connection.
The verified Hobson range includes:
► 400 mm Cyclone Strap Tie Down
► 600 mm Cyclone Strap Tie Down
Both are 25 mm wide & 1.2 mm thick & use G300 structural steel with a Z275 galvanised finish.
Select the length required by the connection detail rather than automatically using the longer option everywhere.
Check Whether the Strap Needs to Wrap Under the Member
Connection geometry can change the way the strap develops uplift resistance.
Hobson advises that Cyclone Tie Down Straps can be wrapped under members to increase uplift resistance where that configuration forms part of the applicable installation.
The decision should be made from the required connection detail before fastening begins.
Allow enough access around the timber to position the strap correctly.
Confirm the Nail Requirement
A structural strap only becomes a connection once the specified fixings secure it to the timber.
Hobson's product data identifies a 2.80 mm nail size for the 400 mm & 600 mm Cyclone Strap configurations.
Check the current installation information for the complete connector-nail requirement, including the required fixing arrangement.
Don't substitute general-purpose nails simply because they fit through the punched holes.
Review the Material & Finish
The product specification includes more than its dimensions.
Hobson Cyclone Strap Tie Downs use G300 structural steel with a Z275 galvanised finish.
Consider the project environment, timber treatment, adjoining components & construction documentation before installation.
Where exposure conditions call for a different material specification, don't assume a Z275 product can be substituted without appropriate confirmation.
Order From the Framing Schedule
Counting roof connections gives purchasing teams a more dependable quantity than estimating from building area.
Review each nominated truss, rafter, purlin or lintel connection & establish the strap configuration required.
Separate 400 mm & 600 mm quantities before ordering so the framing crew can identify each configuration easily on site.
Allow project documentation to determine quantities rather than assuming every roof member receives an identical tie-down.
400 mm vs 600 mm Hobson Cyclone Strap Tie Downs
Both products belong to the same family but length remains an important part of the connection specification.
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Specification
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400 mm Cyclone Strap
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600 mm Cyclone Strap
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Hobson product family
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Cyclone Strap Tie Down
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Cyclone Strap Tie Down
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Material
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G300 structural steel
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G300 structural steel
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Finish
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Z275 galvanised
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Z275 galvanised
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Width
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25 mm
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25 mm
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Thickness
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1.2 mm
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1.2 mm
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Nominal length
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400 mm
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600 mm
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Nail size identified by Hobson
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2.80 mm
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2.80 mm
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Primary selection point
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Required connection detail
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Required connection detail
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Choose the length specified for the framing connection rather than treating 600 mm as an automatic upgrade from 400 mm.
Cyclone Strap vs Wall Bracing Strap
These products may both be metal straps used in timber framing but they perform different jobs.
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Connection Question
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Cyclone Strap Tie Down
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Structural Bracing Strap
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Primary purpose
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Tie down timber members against wind uplift
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Brace timber-framed walls
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Typical orientation
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Around or alongside nominated connected members
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Diagonally across braced wall panels
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Typical Hobson applications
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Purlins, rafters, trusses, top plates & lintels
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Structural wall bracing
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Product format
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Pre-cut punched strap
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Longer punched or unpunched bracing strap
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Selection basis
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Tie-down connection detail
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Wall-bracing detail
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Installation approach
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Specified strap & connector-nail arrangement
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Bracing layout, fixings & tensioning
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Similar appearance doesn't make structural straps interchangeable. Use the product designed for the connection shown in the framing documentation.
Expert Tips for Cyclone Strap Installation
Mark Tie-Down Locations Before Roof Framing Advances
A clear connection schedule prevents straps being discovered as missing after access becomes difficult.
Identify the required tie-down positions before surrounding roof work conceals the timber junctions.
Crews can then install & check each strap as the corresponding framing member reaches position.
A simple site sequence can prevent substantial rework later.
Keep 400 mm & 600 mm Straps Separated
Two lengths from the same product family can look surprisingly similar in a busy framing area.
Store or distribute each configuration separately & retain clear product identification.
Where both lengths occur on one project, mark their intended locations on the framing plan or material schedule.
This reduces the chance of a correct product being installed in the wrong connection.
Check the Timber Before Fixing
Tie-down hardware needs sound timber at every fixing location.
Inspect the relevant top plate, lintel, truss, rafter or purlin before installing the strap.
Splitting, damage, unexpected penetrations or other problems around the connection should be addressed rather than hidden beneath the metal strap.
Good hardware doesn't compensate for unsuitable material at the fixing point.
Position the Strap Without Unnecessary Twists
Clean alignment makes the connection easier to install & inspect.
Lay the strap against the timber in the orientation required by the connection detail.
Avoid unnecessary distortion simply to reach a convenient nailing location.
Where the specified geometry can't be achieved, check the framing arrangement before modifying the connector.
Plan Wrapped Connections Before Access Closes
A strap that needs to pass beneath a member requires space to get there.
Where the installation calls for the Cyclone Strap to wrap under the supporting timber, establish that arrangement while the member remains accessible.
Trying to introduce a wrapped connection after adjacent framing has been completed can create unnecessary difficulty.
Sequence the work around the connection rather than treating the strap as the final item.
Use the Specified Connector Fixings
The punched holes provide fixing positions but they don't make every nail suitable.
Check the current Hobson information & applicable construction detail before fastening.
Keep the required connector nails with the Cyclone Straps when materials are distributed to the framing area.
That small preparation step helps prevent unsuitable substitutions when crews are working through repeated connections.
Inspect Tie Downs Before They Disappear
Structural hardware is easiest to verify while every edge, nail & timber member remains visible.
Review strap location, orientation, required wrapping & fixing arrangement before roofing, linings or other construction restrict access.
Correct anything that doesn't match the nominated detail at this stage.
Where installation records are required, photograph completed connections while they remain unobstructed.
More From The Black Print
Roof tie down is one part of a much larger fastening system, so good preparation extends from connector selection to the tools & hardware available across the job.
► Fastener Guide Bolts Screws Anchors – understand common fastening systems used across Australian construction & installation work
► Spring Jobsite Prep Getting Your Gear Ready – prepare hardware, equipment & consumables before busy construction periods
► A tool is not just a tool. It’s a promise. – a practical look at dependable equipment & the role it plays in completing trade work
