Timber Landscaping

Timber for Landscaping Accoya Wood BridgeTimber for Landscaping

One of the most important things for Landscaping is Durability. We have listed out different types of timbers and their character, grouped by colour below. It is worth noting that sapwood is not durable at all when talking about the durability, we are referring to the heartwood. Occasionally some boards will have a small amount of sap on the edge and this will either needed to be removed prior to use or it will eventually rot.


All timber, if left outside uncoated, will naturally turn a silvery-grey colour. This is a natural process as the outer layers of the timber cellulose get exposed to the weather.  

The timber will also, split, check and warp, but depending on the species this may not be too noticeable.  One way to reduce weathering and distorting of timber is to coat it with a protective product, Refer to our Coatings page for outdoors.

One of the main things to consider when trying to decide whether to coat your timber or leave it to weather naturally is, if you are willing to maintain periodically.  All exterior coatings will need maintenance on an annual basis (usually just a good clean), and they will require recoating every 6 months to 5 years, depending on the coating and its exposure to the elements.

Timbers Suitable for Exterior Use

Colour Timber Durability
Yellow Yellow Cedar Very Durable
Yellow / Light reddish-brown Balau Durable
Golden yellow / Light brown Macrocarpa Moderately Durable above ground
Golden yellow / Light brown Oregon Moderately Durable
Golden yellow / Light brown Totra Very Durable
Light Pink Taun Moderately Durable
Pink Saligna Durable above ground
Pink / Light brown Cedrela Durable
Light brown Sapele Mahogany Durable
Light brown Vitext Durable
Light brown Western Red Cedar Durable
Straw brown Pilularis (Black Butt) Durable
Medium brown Teak Very Durable
Grey to Reddish/dark brown Spotted Gum Durable
Yellow, fading to Dark brown Iroko Durable
Red, fading to Dark Brown Bubinga Durable
Red/Redish-brown, fading to Dark Brown Jarrah Durable
Red/Redish-brown, fading to Dark Brown Padauk Durable
Red/Redish-brown, fading to Dark Brown Rosewood Very Durable
Red/Redish-brown / Dark Brown Kwila Durable

Western Red Cedar


A light timber with a distinctive odour it is non-resinous and straight-grained, with obvious growth rings. Assumes a uniform reddish-brown colour once dried, after long exposure wood becomes silver grey, this weathered look is often sought after.

It is one of our 3 recommended species for weatherboards!

Sustainability: This wood species is not listed in the CITES Appendices, and is reported by the IUCN as being a species of least concern. We only supply PEFC certified Western Red Cedar.

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Botanical Name: Thuja plicata
Other Names: Cedar, Giant Arbor Vitae, Red Cedar
Origin: North America


Certifications Available::
Seasoning: Smaller sizes dry easily, larger boards need extra care to prevent internal checking and collapse. Almost no tendencies to warp and check once dry with little swelling or shrinking movement.
Working Qualities: The timber is easily worked, but its brittle nature can cause splintering also its soft character can lead to chip-bruising. Care should be taken when planning and moulding, sharp cutters will also help create a nice finish. Stains and paints well.
Uses: Interior panelling, fine furniture, interior and exterior joinery, weatherboards and cladding.
Price (1-10): 5


Stocked: Yes
Grade Description: Premium Clears No.1 PC1 is the highest grade of Western Red Cedar imported into NZ. It is primarily sourced from the coastal forests of British Columbia, Canada. The grade is generally considered a ‘clears’ grade with a small number of allowable knots and defects per metre. The timber is visually graded so up to 5% may be considered out of grade or below grade. End splits are a characteristic of the drying process. End splits are allowable up to the length of the width of the profile. I.e. for an ex 200mm profile an end split up to 200mm is within grade. These natural imperfections are generally docked out by the user, but this will depend upon the end use requirements. It is the responsibility of the Builder/Installer to ensure the grade being used is compliant to the required building code or consent issuing authority requirements. Refer to compliance section below. Premium Clears No.2 PC2 is similar to PC1 except there is a higher percentage of knots and defects allowed per metre. These natural imperfections are generally docked out by the user but this will depend upon the end use requirements. PC2 grade generally means there will be a shorter length spread as a higher number of excluded knots and defects results in a more boards being docked, and therefore percentage of wastage may be higher. Compliance Although every care is taken to ensure the timber in each grade is within the grade specification, it is the responsibility of the Builder/Installer to exclude knots, defects and splits that will not be compliant to the required building code or consent issuing authority requirements. Generally, for external cladding applications, knots that are ‘loose,’ ‘bark-encased’, or liable to fail should be removed. Any knot that contains star-checks and splits that will allow moisture ingression must also be removed. Tight inbound knots that pose no weathertightness risk and that will remain sound for the expected serviceable life of the cladding system may be allowed under current guidelines outlined in the NZ building code, and considered a natural feature of Western Red Cedar.
Photos of Western Red Cedar http://www.timspec.co.nz/News--Info/Image-Gallery-s155205-1110.htm


Primary Suppliers: Western Forest Products
Resource Certification: CSA (which is PEFC)


Durability Above Ground: Durable


Density Air Dry: 385 kg/m3


Shrinkage Radial: 2.1 %
Shrinkage Tangental: 4.5 %


Stability Kiln Dry: Very stable
Stability Green: Stable

Mechanical Properties

Janka Hardness: 1.6 kN
Modulus of Rupture: 53 MPa
Modulus of Elasticity: 7.7 GPa
Max Crush Strength: 35 MPa
Strength Group unseasoned: S7
Strength Group Seasoned: SD7
Comp Strength Perp to Grain: 3.4 MPa
Shear Strength Parallel to Grain 5.6 MPa


NZAS lgnitability: 14
NZAS Flame Spread: 10
NZAS Heat Evolved: 9
NZAS Smoke Developed: 4
ASTM Flame Spread: 70
ASTM Smoke Developed: 213

Phone our sales team on (09) 620-0260 or Email us anytime, we'd be happy to help.


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