Unseasoned Sawn & Dressed

Product & Installation Information

Australian cypress (Callitris Glauca) like all timbers is a "natural" material and is subject to dimensional movement with change in seasonal conditions. The following points should be observed to assist installation:

TRANSPORT AND ON-SITE STORAGE

Ensure suitable on-site storage location is available before delivery. All Cypress should be protected from the elements during loading, transportation and unloading. Store under cover protected from the elements, direct sun and where the atmospheric moisture content is similar to the level expected on your building. Timber packs should be stored at least 50mm off the ground/concrete, with even supports to maintain
straight boards and to allow good ventilation to all pack faces. Dressed Cypress comes wrapped in plastic for transport and minimal on-site storage and should not be exposed to direct sun as this limits air circulation and may cause sweating. Do not store on fresh concrete floor as timber will absorb this moisture.

IF UNSURE PLEASE CONTACT US
www.frencham.com.au  Ph.03 5245 8004

CYPRESS

  • Cypress is a durable timber with high termite resistance, making it ideal for structural applications such as house, pergola and deck framing. As a Durability Class 1 timber (above ground), and a Durability Class 2 timber for in-ground applications, it is most suited to beams and posts in external applications.
     
  • Cypress is naturally durable due to its high oil/resin content, however there is no leaching of tannins to stain concrete, brickwork, etc.
     
  • For standard sizes of sawn cypress (unseasoned), refer to Table below.
     
  • As Cypress is a low shrinking timber (approx. 2%) generally structural material is supplied unseasoned. (ie: A piece of unseasoned cypress 100mm wide, when fully seasoned may reduce in size to approx. 98mm)
  • Being unseasoned, it is recommended that cypress be end sealed immediately after docking, to reduce end splitting, with a Timber End Sealer ('Logshield Clear' or similar). If the cypress is to be coated (eg. oil, paints, etc) then use the product coating as an end sealer. This needs to be applied liberally and may require several coats.
     
  • For in-ground applications it is recommended that the docked end be coated with Bituminous paint or a preservative treatment.
     
  • Where sapwood is present, (the white portion of cypress) this should be located above ground, as the sapwood is not as durable as the heartwood.
     
  • Australian Cypress can be left untreated to weather naturally to a "silver-grey", however to give a more "even greying" and assist in prolonging the service life of the cypress, a quality pre-treatment should be applied. refer to: Finishes on our website.
     
  • Structural material may be dressed, however, in external applications, experience has shown that sawn cypress provides a greater long term weathering ability, a better surface 'key' for coating, and is less prone to surface checking than dressed cypress.
     
  • Dressed Cypress where used in an external application has the potential to surface check and crack and should be finished with a quality coating and maintained. This should be done as soon as possible after purchase. Failure to do so will result in surface checking and reduced service life of the product. For more information refer to: Finishes on our website.
     
  • If using dressed cypress, the presence of mill glaze need to be considered. refer to: Finishes on our website.
     
  • For information on the installation of structural cypress, refer to Hints on Fixing.

PROPERTIES OF CYPRESS

Density (kg/m3)

GD: 850

ADD: 750 @ 12%

Hardness kN (Janka)

Green: 5.6

Dry: 6.1

Modulus of Rupture (MPa)

Green: 71

Dry: 79

Modulus of Elasticity (GPa)

Green: 7.7

Dry: 9.0

Crushing Strength (MPa)

Green: 40

Dry: 53

Durability Class (to AS 5604)

Above ground:Class 1

In-Ground: Class 2

Strength Group

Unseasoned: S5

Seasoned: SD6

Joint group

J3/JD3

 

Shrinkage (Low)

Radial %
(Approx.): 2.5

Tangential %
(Approx.): 3.0

Structural Grades

Unseasoned:
F4/F5/Select F7

Seasoned:
F5/F7

Toughness (Nm)

Green: Light

Dry: Light

Early Fire Hazards Indices

Ignitability: 13
Heat Evolved: 7

Spread of Flame: 8
Smoke Developed: 3

Termite Resistance (To AS 3660)

Yes

 

Lyctid Susceptible Sapwood

No

 

HINTS ON FIXING

Whilst a conifer species (softwood), cypress properties relate more closely to those of a hardwood. It has an extremely dense and tight grain, hence care needs to be taken when fixing, as some splitting can occur.

  • When nailing, blunt shear or chisel point nails should be used wherever possible. This type of nail is generally available for 'Finish' and 'Framing' nail guns.
     
  • Where a nail gun is to be used and blunt, shear or chisel point nails are not available, removing the points of the nail to approximately half the point length with a grinder or belt sander prior to installation, will reduce the likelihood of splitting.
     
  • For hand nailing, better results are achieved when the nail points are blunted slightly, with a hammer prior to nailing. For best results, nail holes should be pre-drilled to 80% of the diameter of the nail, particularly when nailing close to ends.
     
  • All screw fixings should be pre-drilled to the root diameter of the screws to be used. For larger diameter screws the application of a small amount of water-proof grease can greatly assist in the installation and durability of the fixing.
     
  • Fixings should be chosen for their corrosion resistance, to suit the environment in which they are to be used.

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