a) Colour fastness:
How far will it fade?
Some product will fade 5% after 2 years and some more than 50%.
WPC with good light fastness will last longer and still looks good aesthetically even after 5 – 10 years.
b) Texture and surface:
Will it collect water?
Collecting water encourage mold/mildew growth and increased slipperiness.
Will it be anti-slip both wet and dry condition?
Slipperiness can lead to falls and injuries.
Deck with an embossed surface has much better anti-slip properties even in wet condition.
The higher the value of co-efficient of friction, the better will be its anti-slip properties
Better deck (WPC) are designed to drain water quickly.
Will the surface of deck cool enough to walk on in a very hot day?
Some deck has a better heat dissipation ability than others and can be walk on without hurting the feet.
Will it grow mould/mildew?
Mould/Mildew is both unsightly and can be detrimental to health.
Mould/Mildew will grow on any substrate that retained moisture.
Once it grows, removing it will be very difficult.
Generally, the less absorbent the substrate, the lesser the chance of growing mold/mildew.
c) Case Histories:
How many years?
WPC with longer case histories and excellent record will tend to continue to perform well as the quality would have been proven.
Weather conditions differ from country to country and location to location.
It is good to have a local or similar reference as a gauge.
Local reference also allows personal view and feel of the WPC project.
d) Hardness and stiffness:
Harder surface means better scratch resistance
Higher stiffness means less deflection, less fatigue on the deck.
e) Solid thickness.
What is the thickness decking material?
Hollow WPC deck or WPC joist cost much cheaper but can cause many problems.