Western Red Cedar - Fixing Guidelines

All data reflects standard industry guidelines - type and number of fixings nominated refers to bullet head nails unless nominated otherwise. 

The fixing specifications referred to below should be regarded as minimum. Greater fixing restraints may be required due to weather exposure and aspects of maintenance as covered in the Fixing Criteria and Fixing Options.

Weather Protected Applications - Hand or Gun Nailing

Internal Wall Panelling & Weather Protected External Cladding

Profile Size Max Span Fixing Face Fixed Concealed
86 x 9 600 30 x 1.6 1 fixing 1 fixing
137 x 9 600 30 x 1.6 * 1            1        
78 x 15 600 40 x 1.6 1          1        
127 x 15 600 40 x 1.6 * 1            1        
78 x 18 900 50 x 1.8 1          1        
127 x 18 900 50 x 1.8 * 1            1        
176 x 18 900 50 x 1.8 * 1           1        
Decor Sections 900 50 x 1.8 1         1        
  * face fixed - 127, 137, & 176 wide profiles may look better with both primary & secondary fixings.
see sketch below for more detail on primary and secondary fixing.

Ceiling & Soffit Lining

              Ceiling or Soffit fixed on top of Exposed Rafters or Purlins
Profile Size Max Span Fixing Face Fixed Concealed
86 x 9 600 40 x 1.6 1 fixing n/a
137 x 9 600 40 x 1.6 2         n/a
78 x 15 750 50 x 1.8 1         n/a
127 x 15 750 50 x 1.8 2         n/a
78 x 18 900 50 x 1.8 1         n/a
127 x 18 900 50 x 1.8 2         n/a
176 x 18 900 50 x 1.8 2         n/a
              Ceiling or Soffit fixed to Underside of Rafters or Purlins
Profile Size Max Span Fixing Face Fixed Concealed
86 x 9 450 30 x 1.6 1 fixing 1 fixing
137 x 9 450 30 x 1.6 * 1            1        
78 x 15 600 40 x 1.8 1         1        
127 x 15 600 40 x 1.8 * 1           1        
78 x 18 600 50 x 1.8 1         1        
127 x 18 600 50 x 1.8 * 1           1        
176 x 18 600 50 x 1.8 * 1          1        
Decor Sections 600 50 x 1.8 1        1        
  * face fixed - 127, 137, & 176 wide profiles may look better with both primary & secondary fixings.
see sketch below for more detail on primary and secondary fixing.

Fixing sizes quoted relate to softwood framing - heavier gauges may be necessary for more dense supports.

For internal and weather protected external applications, bright steel bullet head nails are acceptable.
For sea coast environments, specifiers should consider the additional protection provided by hot dip galvanising.

Weather Exposed Applications - Hand Nailing

Weather Exposed External Cladding

Profile Size Max Span Fixing Face Fixed Concealed
78 x 15 450 50 x 2.8 1 fixing 1 fixing
127 x 15 450 50 x 2.8 * 1            1        
78 x 18 600 50 x 2.8 1         1        
127 x 18 600 50 x 2.8 * 1            1        
176 x 18 600 50 x 2.8 2         N/R        
Decor Sections 600 50 x 2.8 1         1        

  * face fixed - 127 wide profiles may look better with both primary & secondary fixings.
see sketch below for more detail on primary and secondary fixing.

Detail in the Table above reflects good building practice which has proven over time to provide a reliable fixing specification for the majority of 'hand fixed' timber cladding applications.
Where a 'gun fixed' or 
engineered fixing specification is considered necessary (particularly in high wind applications), the Table below nominates alternate options which are engineer certified.

Weather Exposed Applications - Gun Nailing

Weather Exposed External Cladding

Except where specifically noted otherwise, the following nail fixing data is applicable to all softwood (pine) framing with a joint rating of JD5 or better and all hardwood and cypress wall framing.

The fixing references account for both nail withdrawal and head ‘pull through’.

The fixing references only apply where the cladding is fixed direct to wall frames forming an enclosed wall cavity sealed with internal lining. For other wall systems refer to a registered professional engineer.

The nail sizes indicated in the Table below are commonly available hot dipped or mechanically galvanised coil gun nails, as follows:-          

      A = one 45 x 2.5 galvanised flat head (plain or ring shank, head dia. approximately 5.5mm) - one per board for either                    Face Fixing OR Concealed Fixing.
      B = one 50 x 2.5 galvanised flat head (plain or ring shank, head dia. approximately 5.5mm) - one per board for either                    Face Fixing OR Concealed Fixing
      C = two 50 x 2.5 galvanised flat head (plain or ring shank, head dia. approximately 5.5mm) - two Face Fixed
             


Data is applicable to both 15mm and 18mm TIMBECK Western Red Cedar Cladding Profiles.

Non - Cyclonic Regions

Wind
Class'n
General Wall Area
Studs at
Within 1200 mm of Corners
Studs at
  300 450 600 300 450 600

Cover Width 78 mm

N1 / N2 A A A A A A
N3 A A A A A A
N4 A A A A A A

Cover Width 127 mm

N1 / N2 A A A A A A
N3 A A A A A A
N4 A A A A B B (1)

Cover Width 176 mm

N1 / N2 A A A A A A
N3 A A A A B B (1)
N4 A A B B B (1) C

Cyclonic Regions

Wind
Class'n
General Wall Area
Studs at
Within 1200 mm of Corners
Studs at
  300 450 600 300 450 600

Cover Width 78 mm

C1 A A A A A A
C2 A A A A A A
C3 A A A A A B (1)

Cover Width 127 mm

C1 A A A A A A
C2 A A A A B B (1)
C3 A A B B B (1) C (1)

Cover Width 176 mm

C1 A A A A B B (1)
C2 A A B B B (1) C (1)
C3 A B B (1) B (1) C (1) C (1)

NOTE :-

  1. Minimum Softwood Joint Group JD4

 

Primary and Secondary Fixings with Face Fixing

The sketch below is included here specifically to illustrate the difference between
a 'Primary Fixing' and a 'Secondary Fixing'.
For more detail on both Face Fixing AND Concealed Fixing and the benefits of each, see Fixing Options.
 



 

 

Fixing through the face of the cladding with flat head silicon bronze nails OR screws with a flat or distinctive head.
Nails must penetrate at least 32mm into solid framing timbers.
 

For 78 mm boards, the primary fixing is sufficient.

For 127 mm boards, use primary fixing with optional secondary fixing depending on the finished fixing pattern required. 

For 176 mm boards, TIMBECK prefers to see the use of both primary and secondary fixings (irrespective of the structural certification shown above).

 

 

 

 

 

The fixings used on all weather exposed surfaces should be a minimum of hot dip galvanised steel. If bullet head nails are used for face fixing, the resultant nail hole generally requires filling. An alternative to this is to use a fixing with a different head pattern and allow the head to remain proud of the cladding face.

By far, the best options in this category are from the manufacturers of non-ferrous fastenings - deformed shank silicon bronze nails and stainless steel screws.

For silicon bronze nails, similar nail lengths apply but gauge may need increasing when fixing into higher density framing timbers.
 

For face fixing any cladding, the Spax Pacific Decking Screw provides probably the ultimate solution. The outer section of the dual thread device provides the holding required within the cladding thickness allowing incorporation of a much smaller diameter head.

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