Many cladding timbers can be left uncoated to weather naturally - changing in appearance with exposure to the elements, depending on the aspect of the cladding.
The orientation of the cladding on the building will have a material impact on the rate of weathering.
South or west facing are more exposed to both sunlight and driving rain so will weather more quickly. Northerly or eastern facing walls will be shaded and appear darker and may and may require more frequent maintenance.
Shade from a canopy, overhanging trees or nearby buildings may also have a localised impact and cause variations in colour on the same elevation.
Many coating products are available if you wish to counteract these factors, or simply add another dimension to your project. Adding a coating may be a recommendation of the supplier/manufacturer for a particular species or type.
In order to deliver the desired service life, any coating applied must be maintained in good condition in accordance with the manufacturer’s guidance.