Colour changes in timber floors. Over the course of time colour changes occur in timber floors from the effects of ultra violet light. It is usually more pronounced in sun exposed areas of the floor. This is associated with the changes in the timber and with the coating that is applied. Some coatings darken with time more than others and some timbers are more prone to colour changes than others. This process is natural and often gradual but can result in distinct colour differences where rugs have been put on the floor. Some of this change can be minimised by not putting rugs down but ultimately its up to the owner whether they put rugs down or not.